
    514 F. 2d 1041
    AMAX FLY ASH CORPORATION v. THE UNITED STATES
    [No. 261-69.
    Decided April 16, 1975]
    
      
      Gilbert N. Henderson, for plaintiff. Lawrence B. Biebd, attorney of record. Richard A. KiTlworth and Biebel, French (& Bugg, of counsel.
    
      
      James D. Stolces, Jr., with whom was Assistant Attorney General Oarla A. Hills, for defendant. Boland, H. Shubert, of counsel.
    Before Davis, SkeltoN, and Kashiwa, Judges.
    
    
      
       The above-named plaintiff substituted for Dayton Fly Asb Co., Inc., by order of April 4, 1973.
    
   Per Curiam: This case comes before the court on defendant’s exceptions to a recommended decision filed by Trial Judge Hal D. Cooper on May 23, 1974, pursuant to Buie 134(h), having been submitted to the court on oral argument and the briefs of counsel. Upon consideration thereof, since the court agrees with the trial judge’s recommended decision, as hereinafter set forth, it hereby affirms and adopts the same as the basis for its judgment in this case. It is, therefore, concluded that claim 1 of U.S. Patent No. 3,421,587 is valid and infringed and that plaintiff is entitled to recover reasonable and entire compensation for unauthorized use by defendant. Judgment is entered, accordingly, for plaintiff with the extent of defendant’s liability to be determined in further proceedings pursuant to Buie 131(c) (2).

OPINION OP TRIAL JUDGE

Cooper, Trial Judge:

Plaintiff alleges unauthorized use by defendant of an invention described and claimed in its U.S. Patent No. 3,421,587, entitled “Method For Mine Fire Control,” issued January 14,1969, in the names of Heavilon, Jones, and Thomas.

At issue is defendant’s liability under 28 U.S.C. § 1498 for mine-fire control work performed at Monongahela City, Pennsylvania, by the Bureau of Mines. Defendant denies any infringement of the patent, but asserts it is invalid and unenforceable, in any event. In addition, defendant contends that an employee of the Bureau of Mines, Malcolm Magnu-son, was the originator of the process used at Monongahela City and that the patentees derived the invention from him. Alternatively, defendant maintains that Magnuson was, with the patentees, a coinventor of the process. Finally, it is contended that defendant has the right to use the invention without liability either by reason of being a joint venturer with plaintiff during its development or by reason of an implied license.

For the reasons stated hereinafter, none of these defenses can be sustained and it is concluded that plaintiff is entitled to recover.

The technical subject matter in this suit relates to fly ash and a method for its use in controlling fires in abandoned mines. Abandoned-mine fires have a long history in Allegheny County, Pennsylvania, many of them burning for years, creating a health hazard, generating pollution, and inducing subsidence of the land surface. Responsive to the problems associated with these fires, both state and federal programs have been developed to combat them. The Bureau of Mines has been active in mine-fire control work since at least as early as 1949 when it created a Fire Control Group, with headquarters at Pittsburgh, Pennsylvania. By legislation enacted in 1954, funds were provided both for control and extinguishment of mine fires, and for conducting research in connection with such fires. By 1967, the Bureau had substantial experience in this field and had developed a number of techniques, including surface sealing, trenching, loading out, and water flushing, for fighting fires in abandoned mines.

The patent proposes a method of controlling mine fires by pneumatically injecting a mixture of air and fly ash down a borehole into the mine cavity. Fly ash is the residue resulting from the combustion of ground or pulverized coal and is carried from the boiler by flue gases. Separated from the flue gases, it appears as a finely divided powdery substance. When mixed with air, fly ash flows like water; in a settled and aerated condition, it has an angle of repose (the angle the sides of a pile of fly ash form with the horizontal) of only about '8° to 10°. Although some commercial uses of fly ash have been found, it is generally regarded as a waste product.

According to the patent, pneumatic equipment such as a tanker is used to mix air with the fly ash and inject the mixture into the mine. Despite its water-like characteristics, the powdery fly ash creates a barrier of fly ash, from the floor to the roof, through which the fire will not burn. Due to the pressure under which it is injected, the fly ash is carried by the air into the cracks and fissures in the cavity through which air would otherwise be supplied to the fire. By forming an incombustible barrier completely blocking off the mine cavity, and by filling all the small cracks and voids, the fire is denied air and will ultimately die out. The patent further proposes to inject the fly ash directly onto the fire as a means of smothering it. Also contained in the patent is the disclosure that the barrier of fly ash formed in the mine cavity will provide support for the overburden, thereby preventing subsidence of the surface.

The patented process was developed in mid-1967 following a meeting between defendant’s employee Magnuson and plaintiff’s employee Heavilon. It is this meeting, together with a demonstration at Monessen, Pennsylvania, in July 1967, in which both parties participated, that gives rise to the inventorship and license issues in this case. However, before reaching those issues, validity and infringement will be considered.

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Defendant contends that claim 1 is obvious under 35 U.S.C. § 103. Claim 1 is as follows:

A process of controlling a fire in or supporting the earth above an underground mine shaft or other earth cavity, comprising the steps of drilling a plurality of spaced holes through the overburden into the mine shaft, mixing air and finely granulated non-combustible fly ash having a size which permits at least 90% to pass through a 50-mesh screen and 75% to pass through a 325-mesh screen, injecting said mixture into the holes to fill the mine shaft beneath the holes with the fly ash, said injecting step having a sufficient volume and pressure of air so that the fly ash is carried by the air into the cracks and voids through which the air escapes to fill such cracks and voids with the fly ash, said injecting step including filling the mine shaft with fly ash along a substantial length of mine shaft to a depth equal to tbe vertical height of the mine shaft to create a fly ash barrier through which fire cannot burn and to provide vertical support for the earth above the mine shaft, and then closing and sealing the holes.

In support of this defense, defendant relies principally on Anderson et al patent No. 3,152,842, Schmidt et al patent No. 2,710,232, and Bureau of Mines Report 4808.

The Anderson patent discloses a typical bulk pneumatic tanker of the type usable in practicing the patented method. It is undisputed that dry fly ash was being transported commercially by such tankers prior to the invention and that plaintiff was using such tankers in its business. The patent adds nothing to what was concededly the commercial method of transporting fly ash.

The Schmidt patent and Report 4808 both relate to a coal gasification experiment conducted at Gorgas, Alabama, by the Bureau of Mines in 1950. The purpose of the experiment was to gasify coal by igniting a coal seam and flowing air into contact with it. To enhance the contact between the air and the coal face, á barrier was formed in the mine cavity by pneumatically injecting sand through a borehole. This barrier served to retain the subsequently injected air in direct contact with the burning coal, thus enhancing the gasification process.

The experiment is covered in detail in Report 4808. The Schmidt et al patent discloses the method and apparatus used at Gorgas for fluidizing the sand and injecting it into the mine cavity.

There are substantial differences between the claimed method and this prior art, as well as the other prior art cited by defendant. Suffice to say there is nothing in any of the prior art references suggesting the pneumatic injection of aerated dry fly ash for mine-fire control work, or indeed, the use of any similar dry powdery material having a low angle of repose for building a barrier, whether for mine-fire control or surface-subsidence prevention. In view of these differences, the question is whether it was obvious to one of ordinary skill in 1967 to utilize a method of building a structural barrier by employing only air and a dry powdery material.

The unobviousness of the method is, in large part, demonstrated by the known disadvantages of the techniques heretofore employed by the Bureau in fighting mine fires. For example, defendant had previously used fly ash in a water slurry that was injected into the mine to build a barrier. One problem with the water-slurry method was that it was difficult to contain the fine particulate material; the water tended to drain away, carrying with it the small particles from which the barrier was to be constructed, and causing extensive settling. Fly ash, when aerated, exhibits the characteristics of water; hence, aerated fly ash would have suggested to those skilled in the art the very disadvantages with which they were familiar.

Belated to this is the dusty, powdery nature of dry fly ash of the size specified in the claim. When dry fly ash is mixed with air and blown into a mine, the problem of confining the fly ash to build a structural barrier would appear to be severely aggravated. Indeed, when the process was first proposed, Bureau employees anticipated that the fly ash would simply dissipate as dust, instead of forming a barrier. Yet, a superior structural barrier is in fact formed by the claimed process.

Moreover, the patented process requires the injection of air into the mine. The use of air is directly contrary to the usual fire-control practice of denying air to the fire. This was another objection initially expressed by the Bureau.

Facts such as these distinguish this case from those in which the natural evolution of the art pointed the way to the claimed invention. Bather, the instant invention, by employing materials and process steps that, to one of ordinary skill, suggested problems rather than a solution, proceeds in a direction contrary to the prior art. This strongly supports the unobviousness of the claimed process. United States v. Adams, 383 U.S. 39, 52 (1966).

Other considerations support this conclusion. The lack of pertinence of the Gorgas experiment as a mine-fire control technique is demonstrated by the fact that, when the experiment was concluded and it was desired to extinguish the fire in the mine, water was pumped into the mine for 8 weeks to inundate the fire. The inundation technique was used despite the fact that there were, on the orgas site, both a powerplant that was a source of fly ash and pneumatic-injection equipment.

The failure of others, including those highly skilled in the pertinent art, to propose this method is also a factor to be considered. Palmer v. United States, 191 Ct. Cl. 346, 423 F. 2d 316 (1970), cert. denied, 400 U.S. 951; Jones Knitting Corp. v. Morgan, 361 F. 2d 451, 457-58 (3d Cir. 1966). Fly ash is an old, well-known material. The Bureau, in addition to the Gorgas work in 1950 and early projects in which fly ash had been water flushed, had experimented with pneumatic injection of various materials such as mineral wool and sand. Also, gravity injection of dry sand, slag, and rock dust had been attempted. In 1966, the Bureau gave extended consideration to the use of fly ash but decided to use it in the conventional water-slurry process. Significantly, notwithstanding all of the prior work that is now asserted to render the invention obvious, it did not occur to any of these highly skilled people to try pneumatic injection of aerated dry fly ash. This failure of others, long occupied with the problem of mine-fire control, to propose the patented method, undercuts the contention the invention was obvious. LaSalle Street Press, Inc. v. McCormick & Henderson, Inc., 445 F. 2d 84, 93 (7th Cir. 1971); Blaw-Knox Co. v. Barber-Greene Co., 176 USPQ 214 (N.D. Ill. 1972), aff'd without published opinion, 180 USPQ 294 (7th Cir. 1973).

The reactions of those skilled in the field, once the invention was developed, is also a pertinent consideration. AMP, Inc. v. Molex Products Co., 329 F. Supp. 1364, 1373 (N.D. Ill. 1971); Hunt Industries, Inc. v. Fibra Boats, Inc., 299 F. Supp. 1145, 1149 (S.D. Fla. 1969). Almost immediately after the process was demonstrated, fire-control projects, originally planned to use a water-slurry injection technique, were altered by the Bureau of Mines to require pneumatic injection of dry fly ash. News articles hailed the process as one having great promise. Subsequent work by the Bureau at its experimental mine confirmed that the claimed process had substantial advantages over prior techniques, and employees of the Bureau extolled its virtues. It is also significant that the Bureau itself viewed the process as new and unobvious in a patentable sense, and sought, through an application filed by its employee Malcolm Magnuson, to obtain a patent on it.

In summary, considering the state of the art in the field of abandoned-mine fire control, the level of skill in that art, the differences between the claimed process and the prior art, and the relevant secondary considerations, Graham v. John Deere Co., 383 U.S. 1 (1966), it is concluded that the process of claim 1 was not obvious within the meaning of 35 U.S.C. § 103 and that, therefore, claim 1 is valid.

INFRINGEMENT

Defendant argues infringement has not been demonstrated because it has not been shown that fly ash of the claimed size was in fact used at Monongahela City. Defendant also asserts that it did not employ a method which included the step of “closing and sealing the holes” as required by the claim.

Neither contention can be sustained. The specification for the Monongahela City project expressly required the use of fly ash having the claimed size. Further, the evidence is that the method employed at Monongahela City was the same as that earlier employed by defendant on a mine-fire control project at Lloydsville, Pennsylvania. Defendant’s analysis of the fly ash indicates that the fly ash used at Lloydsville fell within the claimed range of sizes.

In view of the evidence, and since defendant offered no evidence to the contrary, the only inference is that this limitation of the claim was present. Palmer v. United States, supra; cf. Marconi Wireless Telegraph Co. v. United States, 99 Ct. Cl. 1, 57-59 (1942), modified on other grounds, 320 U.S. 1 (1943).

As to the closing and sealing step, defendant, instead of leaving the casing in the ground and capping it, pulled the casing and filled the hole with dirt. Quite literally, this is a “closing and sealing” of the hole and is the full equivalent of capping a casing.

Plaintiff has sustained its burden of demonstrating infringement of claim 1. Autogiro Co. of America v. United States, 181 Ct. Cl. 55, 384 F. 2d 391 (1967), rehearing denied, 184 Ct. Cl. 801 (1968).

INVENTORSHIP

As noted above, the inventorship issue centers around a meeting on June 29, 1967, between Malcolm Magnuson, an employee of the Bureau of Mines, and Jerry Heavilon, one of the named-inventors and an employee of plaintiff. That meeting was initiated by Magnuson to obtain information regarding the bulk pneumatic tanker trucks plaintiff was using to transport fly ash. Neither Magnuson nor Heavilon could recall critical aspects of the conversation held on that day but it is undisputed that, when the two men parted, they had agreed that a test would be conducted, at a site to be selected by Magnuson, in which plaintiff would pneumatically inject dry fly ash down a borehole into a mine cavity.

On July 19, 1967, the test was conducted at Monesson, Pennsylvania, the site selected by Magnuson. Using plaintiff’s equipment, fly ash was injected pneumatically down both a cold borehole and a borehole directly over the fire burning in the underground mine. Both Heavilon and Magnuson were present at the test and they, as well as all others present, believed it to be a success.

Thereafter, and in the following sequence, the Bureau of Mines issued a specification calling for pneumatic injection of dry fly ash as a fire-control method, plaintiff filed its patent application, and, substantially later, Magnuson filed a patent application claiming essentially the same method as the patent in suit.

As its principal attack on inventorship, defendant vigorously maintains that Magnuson was the originator of the claimed process and that Heavilon, during the course of the meeting on June 29,1967, derived the idea from him. Plaintiff, with equal vigor, denies that this is the case.

The parties are in general agreement as to the applicable law. To sustain its defense of derivation, defendant must show that Magnuson had both a prior conception of the invention and that he disclosed it to Heavilon. Shumaker v. Paulson, 136 F. 2d 700, 703 (CCPA 1943).

The conception must be more than the realization of a desirable result, Garrett Corp. v. United States, 190 Ct. Cl. 858, 422 F. 2d 874 (1970), cert. denied, 400 U.S. 951, and more than a mere hope or expectation, Alpert v. Slatin, 305 F. 2d 891, 894 (CCPA 1962).

It is said that conception has been achieved when “the inventive idea is crystallized in all of its essential attributes and becomes so clearly defined in the mind of the inventor as to be capable of being converted to reality and reduced to practice by the inventor or by ones skilled in the art.” Technitrol, Inc. v. United States, 194 Ct. Cl. 596, 609, 440 F. 2d 1362, 1369-70 (1971).

It is the usual rule that a claim of prior conception requires corroboration. Kardulas v. Florida Machine Products Co., 438 F. 2d 1118, 1121 (5th Cir. 1971); Westinghouse Electric Corp v. Bulldog Electric Products Co., 106 F. Supp. 819, 873 (N.D. W. Va. 1952), aff'd, 206 F. 2d 574 (4th Cir. 1953), cert. denied, 346 U.S. 909. However, the existence of corroboration is to be determined by viewing the evidence as a whole. Richardson v. Cook, 442 F. 2d 1398 (CCPA 1971); Beeber v. Krogh, 403 F. 2d 743 (CCPA 1968).

Once conception has occurred, the inventor may use the services and assistance of others to perfect his invention without losing his right to a patent. Hobbs v. United States Atomic Energy Commission, 451 F. 2d 849, 864 (5th Cir. 1971).

The parties’ principal disagreement on the law is as to the standard of proof applicable where the defense of derivation is asserted. Plaintiff maintains that the evidence must be “clear and convincing” while defendant insists that only a “preponderance” is required.

Plaintiff’s position is the correct one. The inventors as named in an issued patent are presumed to be correct. Acme Highway Products Corp. v. D. S. Brown Co., 431 F. 2d 1074 (6th Cir. 1970), cert. denied, 401 U.S. 956 (1971); Mueller Brass Co. v. Reading Industries, 352 F. Supp. 1357 (E.D. Pa. 1972), aff'd without opinion, 487 F. 2d 1395 (1973). Claims of prior inventorship are “subjected to the closest scrutiny,” The Barbed Wire Patent, 143 U.S. 275, 285 (1892), and “evidence to prove prior discovery must be clear and satisfactory,” Eibel Process Co. v. Minnesota & Ontario Paper Co., 261 U.S. 45, 60 (1923). Since conception is an act of the mind, 1 Rivise & Caesae, INTERFERENCE Law and Practice § 118 (1947), the temptation for even honest witnesses to reconstruct, in a manner favorable to their own position, what their state of mind may have been years earlier, is simply too great to permit a lower standard. The Barbed Wire Patent, supra; Acme Highway Products Corp., supra. Nor is the standard of proof any lower when a prior conception is asserted as the basis for a derivation argument. Egnot v. Looker, 387 F. 2d 680 (CCPA 1967); Williams v. Clemons, 19 F. 2d 798 (D.C. Cir. 1927).

Thus, to sustain its defense of derivation, defendant must first show, by clear and convincing evidence, that Magnuson had a prior conception of the claimed subject matter. Since the conception must have been of the invention defined in the claims, Ritter v. Rohm & Haas Co., 271 F. Supp. 313, 323 (S.D. N.Y. 1967), it is well that an analysis of this issue starts with the claim itself.

Claim 1 is a method claim, delineating certain method steps to be employed while using certain defined materials to accomplish a specified result. The materials specified are air and fly ash, with the fly-ash size being so defined that it is in the nature of an essentially powdery substance. Using these two defined materials, the claimed method specifies, first, mixing the air with the powdery fly ash and, second, injecting the mixture under sufficient volume and pressure of air into a mine cavity so that the injecting air carries some of the fly ash into the cracks and voids while depositing the remaining fly ash to build up an incombustible structural barrier from the floor to the roof along a substantial length of the mine. It is this claimed invention that is the focal point around which, the inquiry into prior conception must revolve.

In the context of the claimed process, it is well to note at the outset that it is insufficient, on the issue of prior conception, merely to show prior knowledge of the broad idea of hooking up a pneumatic tanker to a borehole extending into a mine cavity. Father, it must be shown that, in addition to this broad idea, there was a realization, in finite terms, of the means or process steps by which the desired result of extinguishing a fire would be achieved. Gathmann v. Clarke, 45 App. D.C. 512 (1916); Forgie v. Oil-Well Supply Co., 58 F. 871 (3d Cir. 1893); Biel v. Chessin, 347 F. 2d 898 (CCPA 1965); I Robinson ON Patents § 79 (1890).

Turning then to the issue of whether Magnuson, prior to June 29, 1967, had a conception of at least the critical features of the claimed invention, the evidence falls substantially short of being clear and convincing that he did. Magnuson testified that he first learned about bulk pneumatic tankers for hauling fly ash on June 26, 1967, during the course of a chance conversation with Donald Nagode and Jesse Cutlip. Both of these men were familar with fly ash and the use of bulk tankers for transporting that material. During the course of this conversation, Nagode explained how the tankers were used to blow dry cement or dry fly ash into storage bins and commented that if fly ash could be blown up into bins, it could be blown down into a mine. Nagode and Cutlip then briefly outlined the operation of these tankers to Magnuson and suggested that he contact plaintiff for any further information. Thereafter, Magnuson attempted to obtain, over the telephone, some additional information regarding the trucks but was referred to Heavilon and a meeting was then set up for June 29,1967.

Although Magnuson testified that Nagode’s disclosure of the existence of pneumatic tank trucks “looked like the answer to what we were wrestling with here these months about the use of fly ash,” the evidence does not satisfactorily demonstrate that this “answer” was a conception of the claimed invention. Magnuson did not amplify his testimony in this respect so it is uncertain what he conceived to be the “answer.” However, he had no experience with dry fly ash and uq specific knowledge about pneumatic tankers, how they operated to aerate fly ash, and their injection pressures. Further, he believed dry fly ash would plug the borehole, that the injection of air into the mine might feed the fire much like a forge, and that injecting fly ash under pressure would cause the fly ash to dissipate as dust. It was not until after the demonstration in July and, to some extent, after, some Bureau experiments in October, that Magnuson was satisfied that none of these beliefs was correct.

Since the characteristics of dry fly ash, the mixing of air with fly ash, and the formation of a fly-ash barrier are all aspects of the claimed invention, the foregoing would suggest that whatever answer Magnuson believed Nagode’s suggestion represented, it was substantially less than a firm conception of the process by which a pneumatic tanker could, when connected to a borehole, be operated to inject fly ash to extinguish a mine fire. At best, it would appear that Mag-nuson had a general, vague idea that a pneumatic tanker could be useful in fighting fires but the maimer of using it, the specific process steps by which the desired result could be achieved, were not then perceived by him.

Other evidence in the record lends support to that conclusion. Magnuson’s diary entry following his meeting with Nagode merely referred to Nagode’s suggestion and nothing-more. Thereafter, but prior to the meeting with Heavilon, Magnuson mentioned this subject to no one. This absence of any contemporaneous disclosure of the claimed process, when it allegedly was the answer to a difficult problem, raises substantial doubts that Magnuson went into the meeting with Heavilon with anything more than the generalized suggestion of Nagode that “if you can blow fly ash up, why can’t you blow it down.” This is further corroborated by his forthright admission that, both prior to and after the demonstration, he drew no conclusions as to what had happened to the fly ash once it was down in the mine.

Nor is the evidence satisfactory that Magnuson, even if possessed of the conception, communicated it to Heavilon. He testified that he had no recollection of this but believed that it would have been logical that he would have told Heavilon he was interested in using pneumatic tankers to blow fly ash into a mine. However, both Heavilon and Mag-nuson made written reports or notes shortly after their meeting. Magnuson’s notes offer no indication of who raised the topic of pneumatic injection of fly ash but Heavilon’s notes allocate the suggestion to himself. While the self-serving nature of these notes is apparent, yet they were made essentially contemporaneously with the meeting and long before any controversy had developed. They are, therefore, entitled to some weight. Cf. Pacific Far East Line, Inc. v. United States, 184 Ct. Cl. 169, 894 F. 2d 990 (1968).

In support of its derivation defense, defendant places great stress on the fact that the meeting was initiated by Magnuson, not Heavilon; the superior knowledge of Mag-nuson in the field of mine-fire control; and the fact that only Magnuson had knowledge of Nagode’s earlier suggestion.

That Magnuson is a thoroughly competent and highly respected mining engineer with long experience in the field of mine-fire control is undisputed. Nor is it disputed that Heavilon had no prior experience with mine fires. However, Heavilon had the superior knowledge as to dry fly ash, its characteristics when aerated, and the method of operation of the trucks used to transport and inject the fly ash. While logic, applied to the facts with the benefit of hindsight, may suggest that the one endowed with the greater knowledge would be the more likely to have originated an idea, the instances where the experts have been confounded, see, e.g., United States v. Adams, supra, are too frequent to rely too heavily on logic to establish the fact. Here, the pertinent knowledge was partially held by each so the knowledge factor is an ambiguous one at best.

Nor does the fact Magnuson initiated the meeting necessarily confirm a prior conception. That Magnuson sought the meeting to learn more about pneumatic trucks is clear but the question remaining unanswered by the evidence is as to why he wanted the information and to what use he intended to put the trucks. Was it for the purpose of pneumatically injecting fly ash in accordance with the claimed method? 'Or was he seeking information simply as a first step in a general evaluation of how these trucks might be useful in connection with his work? Or did he contemplate that the trucks, with their long hoses, would provide a possible way for delivering the fly ash directly to the borehole for the water-flushing operation, thereby eliminating the double-handling of the fly ash theretofore required? The evidence, even when considered in light of Magnuson’s knowledge of Nagode’s suggestion, dues not point to any particular conclusion but, rather, supports in varying degrees each one of them.

In the absence of clear testimony by Magnuson as to a specific prior conception, the absence of corroboration either by any witness or by any document as to the fact of such a conception, and in view of the doubts, concerns, and lack of specific information he possessed, it is concluded that defendant has failed to sustain its burden of proving either a prior conception by Magnuson or a communication of that conception to Heavilon.

The second branch of defendant’s attack on inventorship is that Magnuson, if not the prior inventor, was a joint inventor either “with Nagode and/or Cutlip, or with Heavilon, Thomas, and/or Jones.”

Where more or less than the true inventors are named, the patent is void. Iowa State University Research Foundation, Inc. v. Sperry Rand Corp., 444 F. 2d 406, 408 (4th Cir. 1971). However, misjoinder and nonjoinder of inventors are technical defenses requiring clear and convincing evidence. Garrett Corp. v. United States, supra, at 869, 422 F. 2d at 880. A claim of coinventorship is also viewed with skepticism and requires clear and convincing evidence. Acme Highway Products Corp. v. D. S. Brown Co., supra; Mueller Brass Co. v. Reading Industries, supra; Layne-New York Co. v. Allied Asphalt Co., 363 F. Supp. 299 (W.D. Pa. 1973), rev'd on other grounds, 501 F. 2d 405 (1974).

Since tbe chain of events leading up to plaintiff’s filing of its patent application commenced with the Magnuson-Heavilon meeting, the coinventorship argument is, at first blush, an appealing one. However, acceptance of that conclusion requires suppositions and assumptions that are not supported by the testimony of either participant.

The difficulty in finding Magnuson to be a coinventor is essentially the same as that encountered with the derivation defense. There is simply insufficient evidence as to what Mag-nuson may have contributed. If anything, the evidence would suggest that he may have passed along Nagode’s comment to Heavilon. Of course, that would, at best, make Nagode, not Magnuson, a coinventor.

Nor does the fact that Heavilon and Magnuson agreed to conduct a test dictate a conclusion of joint inventorship. When Magnuson left the meeting, it was his understanding that a test would be conducted in which plaintiff would supply one load of fly ash and demonstrate that it could be injected pneumatically down a borehole without plugging the hole. But the fact of their agreement to conduct a test of that character does not resolve the issue of their respective contributions; nor does it clearly indicate that during and after this meeting, and through their united efforts and mutual contributions, Monsanto Co. v. Kamp, 269 F. Supp. 818 (D.D.C. 1967), there evolved the claimed invention. The facts are simply that Magnuson and Heavilon agreed to conduct a test and that Magnuson selected a site and prepared a fitting to permit attachment of plaintiff’s trucks to the borehole casing. To read into or infer from those facts any particular contribution by Magnuson to the claimed process is singularly inappropriate when even Magnuson offered no substantial testimony beyond those facts.

It is concluded that the proofs are insufficient to establish Magnuson as a coinventor. Layne-New York Co. v. Allied Asphalt Co., supra.

The same problem, insufficient proof, is present with the third branch of defendant’s attack on inventorship, which is that Thomas and Jones were improperly joined as inventors with Heavilon,

There is no question but that, as among the three named inventors, Heavilon had the basic idea of pneumatically injecting dry fly ash to seal off the fire. However, after his meeting with Magnuson, Heavilon was uncertain as to what would happen to the fly ash, once it was down in the mine, and had reservations about the efficacy of the process. While Heavilon possessed an idea that encompassed the manipulative step of connecting a pneumatic tanker to a borehole extending into a mine cavity, it has not been shown that this idea extended to all aspects of the claimed process. Nather, the record indicates that it was not until the subsequent meeting with Thomas and Jones that the process was thought through, both as a fire-control technique and as a surface-subsidence measure. Matters such as the lateral travel of the fly ash in the mine, its bulking characteristics when wet, the size, carbon content and angle of repose of fly ash, and injection pressures to use in injecting the fly ash, were discussed by the three men. All of these matters are pertinent, in some degree, to a perception of how fly ash can be injected to achieve the desired results.

In view of this, it cannot be found by clear and convincing-evidence that Thomas and Jones contributed nothing to the final conception of the method as it is expressed in the claims of the patent. See, Mueller Brass Co. v. Reading Industries, supra at 1372.

LICENSE

Finally, defendant argues that it is entitled to a nonexclusive, royalty-free right to practice the patented method by reason of the contributions made by its personnel and the use of its facilities during the demonstration on July 19, 1967.

Plaintiff had no contract with defendant for any aspect of that demonstration, and there was no “close and umbilical connection,” Mine Safety Appliances Co. v. United States, 176 Ct. Cl. 777, 364 F. 2d 385 (1966), with any work being-done under a Government contract. Nor are there any facts from which it might be concluded that the parties were involved in a joint venture. Compare, Technical Development Corp. v. United States, 202 Ct. Cl. 237 (1973), cert. denied, 416 U.S. 983 (1974).

Plaintiff received no compensation from defendant. The expense of the demonstration was almost entirely borne by plaintiff, the only cost to defendant being a fitting it fabricated so that the hoses on plaintiff’s trucks could be connected to the pipes in the 'boreholes. These facts, together with the absence of any contractual relationship, readily distinguish this case from Ordnance Engineering Corp. v. United States, 68 Ct. Cl. 301 (1929), cert. denied, 302 U.S. 708 (1937).

The license defense cannot be sustained.

In summary, it is concluded that claim 1 is valid and infringed, that defendant has no license to use the invention defined therein, and that plaintiff is entitled to recover reasonable and entire compensation for such use.

BINDINGS OP PACT

1. United States Patent No. 3,421,587 for “Method For Mine Fire Control” was issued on January 14, 1969, on an application filed September 20, 1967, jointly by Jerry A. Heavilon, Dennis A. Jones, and Barton A. Thomas, and assigned to plaintiff.

2. Plaintiff was incorporated in the State of Ohio in 1960. On January 1, 1972, plaintiff changed its name from Dayton Fly Ash Co., Inc., the style in which the petition herein was filed, to Amax Fly Ash Corporation.

3. Defendant is charged to infringe the patent in suit by reason of certain mine-fire control activities of the Bureau of Mines, Department of the Interior, in the control of fires in abandoned mineworkings at Monongahela City, Pennsylvania.

4. (a) The patent proposes a method of controlling mine fires by pneumatically injecting a mixture of air and fly ash down a borehole into a mine cavity thereby to create a barrier of fly ash through which the fire will not burn. Due to its powdery nature and the pressure under which it is injected, the fly ash is carried by the air into the cracks and voids through which air would otherwise be supplied to the fire. By forming a barrier completely blocking off the mine cavity, and by filling all the small cracks and voids, the fire is denied air and will ultimately die out. The patent further proposes to inject the fly ash directly onto the fire as a means of smothering it.

(b) Claim 1, the only independent claim, describes a method that involves, (1) drilling a plurality of holes from the surface into the mine, (2) mixing air with fly ash, the fly-ash size being so defined that it is in the nature of an essentially powdery substance, (3) injecting the mixture through the boreholes with sufficient volume and pressure that the injecting air carries some of the fly ash into the cracks and voids while depositing the remaining fly ash to build up an incombustible barrier from the floor to the roof along a substantial length of the mine, and (4) closing and sealing the holes.

5. Fly ash is a finely divided, powdery substance that results from the combustion of ground or pulverized coal and is transported from the boiler by flue gases where it is separated, as by mechanical or electrostatic precipitators. Although it contains a small amount of carbon, fly ash is for all practical purposes incombustible. It is produced in the United States in quantities which substantially exceed the rate at which it is used in commerce, with the excess fly ash disposed of by such means as in landfills. It is estimated that in 1965 only about 3% of the 20 million tons of fly ash produced was used commercially.

6. When fly ash is collected by the powerplant, it is in a dry state. One hundred percent pure dry fly ash, in a tightly packed or solid condition without air spaces or voids between its particles, weighs about 140 to 160 pounds per cubic foot. When it is transported in open trucks, it is necessary to dampen it with about 10 to 14 percent of water to prevent it from blowing away. Its angle of repose in this dampened condition is about 35°.

It can also be loaded into pneumatic bulk tankers and then allowed to settle into its so-called nonaerated condition in which it consists of about 50% air and 50% fly ash by volume. In such condition, it would not be readily discharged by gravity; therefore, unloading requires that additional air must be added to the fly ash in the tanker. Aerated fly ash can be unloaded by a conventional pneumatic tanker at the rate of about one ton of fly ash per minute. Aerated fly ash runs like water and, when it settles, it has a low angle of repose of about '8° to 10°.

7. (a) Mine fires can be divided into two categories: 1) active mine fires and 2) inactive mine fires.

In an active mine fire, the fire is discovered almost immediately and the operator takes immediate steps to control the fire by using hoses or rock dust. The entries surrounding the fire are generally accessible so firefighters can attack the source of the fire directly.

The prevention and control of fires in inactive coal deposits, where there is no operator around, present entirely different problems, and different techniques for fighting the fire are involved. Often, fires in abandoned mines burn for years before steam is observed or the temperature breaks out and the fire is discovered. By this time there is no access to the underground workings and the fire has to be fought from the surface. Furthermore, confusion and indecision often prevail as to the responsibility for taking the necessary action to control a fire in an abandoned mine.

(b) Fires have been known to burn for years in abandoned mineworks. Such fires induce subsidence of the land surface, cause pollution, and present a health hazard when carbon monoxide is liberated. Abandoned mines have a tendency to bum out in one area and propagate in another. There is a long history of mine fires burning in Allegheny County, Pennsylvania, a condition that has existed for many years.

8. Prior to June 1967, fires in abandoned mines were controlled by techniques such as, for example, surface sealing, trenching, loading out, and water flushing.

a) Surface sealing

As a fire burns in a mine, it causes crevices and caving of the surface, and these crevices create chimneys which pull air from other interconnected works. Surface sealing involves filling the crevices at the surface. This is accomplished by plowing the surface with a bulldozer with an angled blade, to a depth of 4 to 6 feet, pulverizing the surface, and covering the cracks and crevices. If this operation has to be carried out in a forest, the trees have to be cleared, the roots pulled up, and the area denuded in order to plow it. In a surface-sealing project, there is usually at least 2 years maintenance because, in cooling down, it is not unusual to get caved areas and additional crevices. A fair-weather inspection road is built over the area so that periodic inspections for cracks, crevices, steam, subsidence, or any other condition that might indicate a disturbance can be carried out.

b) Trenchi/ng

A barrier is formed by digging a trench from the surface, through the coalbed around behind the fire and out on the other side, to isolate the fire and cut off the contiguous working in the coalbed from the fire. The bottom of the trench has a width of 12 to 14 feet and the trench may be as deep as 80 feet. It is then backfilled with the removed material, with the bumables and nonburnables selectively returned to the trench in such a manner that the fire is presented with the nonburn-ables at the level of the coalbed. A variation on this, called a plug barrier, is employed whenever it is impractical to dig a trench all around the fire.

c) Loading out

This simply involves digging out the burning material and spreading it out to cool. Loading out is only feasible if performed shortly after a fire has started.

d) Water flushing

This technique has been used when surface sealing, trenching, or loading out were not practical. Boreholes are drilled from the surface into the coalbed and into the mine cavity, and the cavity at the bottom of the borehole is filled with a solid material conveyed into the hole by water. The materials generally used are granulated slag, sand, and crushed limestone with a maximum size of one-fourth inch. The purpose of water flushing is to fill the void in the mine with the solid material, thereby to prevent air circulation and smother the fire. To accomplish this objective, a series of boreholes, which, for example, may be about 10 feet apart, are drilled and flushed. In this manner one is able to build a barrier and thereby prevent the fire from propagating. This technique can also be used to apply water, and the material being flushed, to the source of the fire, if known. The disadvantages of this method include its cost, the nonavailability of water in some areas, the large quantity of water needed, the necessity to suspend operations during cold weather when water might freeze, the messiness of the operation, the inability to control deposition of the material, the lack of an effective seal at the roof, and the tendency of the material to settle or shrink as the water drains away. Despite these substantial disadvantages, water flushing represented the best solution, prior to mid-1967, to the problem of fighting a fire in a mine that was either too deep or so located that other techniques such as trenching out could not be used.

e) Inundation is another method of mine-fire control. This requires flooding of the mine with water. A major problem with this technique is that crop fires are usually above drainage and it is very difficult to create barriers for holding the water.

f) In 1968 the Bureau of Mines experimented with the pneumatic injection of mineral wool or sand through a borehole to create a remote seal in a mine entry. When this technique was used on an actual mine fire, it was not considered successful because it only sealed about 95% of the entry. The preferred apparatus, developed as a result of this experimental work, used either a bottled inert gas or gases withdrawn from the mine itself as the gaseous medium for conveying the mineral wool into the mine cavity. With this apparatus, introduction of additional oxygen to the burning coal was avoided. This work is reported in Bureau of Mines report HI 6453.

9. Prior to July 1967, the Bureau of Mines had used fly ash in fire-control projects on three occasions. In 1954, damp fly ash, which had been transported in an open truck, was hand-shoveled into crevices in a surface-sealing mine-fire control project. In 1958 and 1959 at Monessen, Pennsylvania, fly ash was used as the flushing material in a water-flushing mine-fire control operation.

10. In 1966 and the first part of 1967, Malcolm Magnuson, a supervisory mining engineer for the Bureau’s mine-fire group, was working on a project to control mine fires at Lloydsville, Pennsylvania, and Monongahela City, Pennsylvania. In connection with these projects, Magnuson had reviewed the advantages and disadvantages of using a water flush to extinguish these fires. Despite a number of objections and potential problems that he anticipated with the use of a fly-ash slurry, he eventually decided that use of this technique would be the method of choice. A prune consideration in the selection of this method was that under the law, the local government was required to purchase the extinguishing material, and the relatively inexpensive nature of the fly ash compared to other materials made it affordable for the local governments. Through the first half of 1967, plans proceeded for using a fly-ash slurry flush at both mine-fire sites. During all this preparation, which involved numerous meetings with many individuals, no one suggested the pneumatic injection of dry fly ash to extinguish the fires.

11. Among those participating at various times in these planned meetings were highly skilled and experienced people, both in the field of mine-fire control and in the field of fly-ash utilization. One of the participants was Gerard Gambs, an employee of Consolidated Coal. Gambs was familiar with fly ash, pneumatic tankers, and mine fires. He was urging water flushing of fly ash as the technique to be used.

12. Magnuson had several reservations about the use of fly ash for water flushing. One concern was the hauling and handling charges. Although the material itself was free, hauling the material was an expense. He devoted significant time to investigating these hauling charges which, in open dump trucks, were in excess of $2 per ton. In addition, unless the flushing holes were accessible to the trucks delivering the fly ash, there was the need for additional equipment to carry the fly ash from where the trucks deposited it over to the borehole. Another reservation he had regarding the use of fly ash was its fine size. He was concerned that the fine fly ash would be carried away by the water instead of settling out to build a barrier as occurs when a coarser material is employed. Also, problems had been encountered with the boreholes being plugged by the material, partly due to the difficulty in mixing the fly ash with the water.

13. On March 14 — 16, 1967, the Bureau of Mines, jointly with the Edison Electric Institute and the National Coal Association, sponsored a fly ash utilization symposium in Pittsburgh, Pennsylvania. Over 500 persons, both from this country and abroad, and all of whom bad a serious interest in fly asb and its utilization, attended tbe symposium. Although a wide variety of uses of fly asb were discussed, no mention was made of using dry fly asb in mine-fire control.

14. (a) On Monday, June 26,1967, Magnuson was observing a conventional plug and surface seal mine fire control project in Eobinson Township, Pennsylvania, and entered into a discussion with Donald Nagode and Jesse Cutlip who were on tbe site also observing tbe project. It was Nagode’s company that was doing this fire-control work. Nagode was also tbe operator of a cement block company in Eobinson Township, Pennsylvania, and used fly asb in this business. Both Nagode and Cutlip were familiar with the fact that dry fly ash was being delivered in bulk pneumatic tankers and blown up through a pipe into surface storage bins of customers such as Nagode.

(b) During the ensuing conversation between Magnuson, Nagode, and Cutlip, the subject matter of mine fires came up, including the technique of drilling holes into the mine and slurrying material in with water, the planned future water flushing of fly ash in the abandoned mine-fire control projects, and the difficulty of mixing fly ash with water.

(c) Nagode mentioned that there were available bulk pneumatic tankers which carried fly ash and suggested that Magnuson could blow fly ash directly therefrom down a borehole into the mine. Nagode explained how such tankers hooked up to a fitting on the bin at his cement block plant to blow fly ash into the bin. As a result of this conversation, Magnuson understood that a tanker did not unload merely by gravity flow but that it would blow fly ash through a pipe and into a bin.

(d) Magnuson at that time was familiar with fly ash but had no experience with dry fly ash; nor was he familiar with the commercially available bulk pneumatic tankers for transporting fly ash. Upon expressing an interest in obtaining more information about the tankers, Jesse Cutlip explained that his son, William C. Cutlip, was employed by plaintiff at its offices near Pittsburgh, in New Eagle, Pennsylvania, and suggested that William could provide Magnuson with more information about pneumatic tankers. Magnuson’s diary for June 26,1967, contains the following entry:

At site talk to Donald Nagode & Jesse Cutlip of Masters Builders about fly ash use. He suggests blower trucks to put fly ash into mine.

15. On June 27,1967, Jesse Cutlip spent the evening with Jerry Heavilon, an employee of plaintiff, to discuss business matters of mutual interest. Cutlip told Heavilon that Magnu-son was interested in having a meeting with him, but the pneumatic injection of fly ash for mine-fire control was not discussed. Cutlip did provide Heavilon some background information on the characteristics of a mine fire and the problems associated therewith. This was Heavilon’s first exposure to mine fires.

16. Following Jesse Cutlip’s suggestion, Magnuson called William Cutlip on June 28, 1967. Although Magnuson does not recall the substance of the conversation, his purpose in calling was to obtain further information regarding the tank trucks and he believed that the information he sought could be obtained over the telephone. However, William Cut-lip advised Magnuson that he did not handle the information requested and arranged to have Magnuson meet with Heavilon on June 29, 1967. Aside from this conversation, Magnuson did not discuss the matter of pneumatic tankers with any one until the meeting with Heavilon.

17. (a) Magnuson and Heavilon met on the morning of Thursday, June 29, 1967, in plaintiff’s office, located in the Mitchell Power Plant of the West Penn Power Company in New Eagle, Pennsylvania. The conversation took place first in the office, then outside in a yard adjacent to the power-plant where a bulk pneumatic tanker was parked, and then at the Monongahela City mine-fire site which was nearby. The meeting lasted about 3 hours.

(b) Magnuson asked Heavilon questions about, and received information regarding, pneumatic tankers, their capacity, loading and unloading time, hauling rates, and rental rates. Heavilon gave Magnuson information about dry fly ash, the types of fly ash available at the West Penn Power Station and, also, showed Magnuson a pneumatic tanker and explained its operation. Heavilon asked Magnuson questions about, and received information regarding, mine fires. Mag-nuson drove bim to tbe nearby Monongabela City site, which Magnuson explained was a future mine-fire control site. Magnuson explained the present wet-flushing operation, the grid system of holes, and the use of mine maps. Heavilon understood from Magnuson that a borehole is taken down to a mine cavity and that soil or other granular material is dumped down into the cavity in a slurry form to fill up the cavity and stop the progress of the fire. He also learned of the use of fly ash, fine clay, limestone dust, and other materials in the slurry.

(c) Neither Heavilon nor Magnuson could recall the meeting with sufficient clarity to testify as to who it was that first brought up the idea of pneumatically injecting dry fly ash. It was Heavilon’s recollection that the subject was first raised while they were at the Monongahela City fire site and that he asked Magnuson whether the contract specifications could be changed to allow dry injection rather than the wet flush of fly ash.

(d) By the time Heavilon and Magnuson parted on June 29, 1967, it had generally been concluded by both that the pneumatic-injection idea should be pursued further by a test to demonstrate that fly ash could be injected without plugging the hole. Heavilon agreed to supply a truckload of fly ash and a particular fitting for the truck for the test, and Magnuson agreed to provide a test site and a special adapter which would permit connection of the hose on the pneumatic tanker with the metal casing of the boreholes that had been drilled into the mine.

18. Subsequently, both Heavilon and Magnuson made notes of that meeting, Heavilon’s being in the form of a call report and Magnuson’s being in his daily diary. Heavilon’s report, written on June 30,1967, is as follows:

Met with Malcolm Magnuson of the B. of Mines with reference to the fire at Mon City. They presently use fly ash, fine clay, limestone dust, etc. to slurry and place in holes drilled on 10' grids by front end loader at a rather prohibitive cost. His first question was about the, cost of fly ash vs. other materials. I told him that the cost would be approx. $1.50 per ton plus trucking. This is comparable to other materials providing fly ash source is close.
At the same time I asked him if dry fly ash could be delivered to the site and blown directly into the mine to seal off the fire. He said he could see no reason that the bids couldn’t be received this way. I couldn’t guarantee him that this would work but that we would be most happy to try this method at their experimental mine in the southern end of Pittsburgh.
This was agreeable to hirn, we furnished him with a Kamlock fitting to make a pipe and fitting to receive a load to test. I expect to run this test within the next three weeks. If it does work, there are approx. 5 mine fires now burning that this method would be applicable. Their usage is approx. 100 ton per day.

Magnuson’s diary contains the following entry for June 29, 1967:

To Mitchell Power Plant at 9:00. Meet Jerry Heavilon Chief engr. Dayton Fly Ash view Blower tank truck for ash delivery — truck capacity 20 tons would rent for about $20.00/hr. Can deliver fly ash 60-100 ft from hole will try to set up test for blowing ash into borehole.

19. Following the meeting with Heavilon, Magnuson spoke about the project with Gerard Gambs, an individual knowledgeable about fly ash as well as pneumatic tankers. Magnuson had two major concerns. Although he had no understanding, as of that time, as to what would happen to the fly ash once it was down in the mine, his immediate concern was whether the dry fly ash would plug up the moist borehole. Magnuson knew from prior experience that most boreholes have moist sides and, in the past, such holes were plugged up when slurries were run through them. His second major concern was the effect of introducing so much air into the mine. He felt that it might act like a forge on the fire. Gambs expressed the belief that pneumatic injection of dry fly ash was a good idea but that it had never been tried before. Gambs and Magnuson discussed the possibility of injecting the fly ash by a combined stream of air and water; however, nothing further was done with that idea.

20. (a) Following the June 29th meeting with Magnuson, Heavilon returned to plaintiff’s main office in Dayton and related the substance of his conversation with Magnuson to Barton. Thomas, Dennis Jones, and John Thomas, who was president of the company. The other two men are employees of plaintiff and are, with Heavilon, the named coinventors of the patent in suit.

(b) Thomas and Jones were experienced in the handling-characteristics of dry aerated fly ash. Jones had particular knowledge as to the physical properties of fly ash, while Thomas had worked with fly ash since the 1950’s and was acquainted with its ability to penetrate small spaces as well as its ability to absorb moisture and become hardened. Thomas had previously used fly ash to smother surface fires.

(c) Heavilon explained his idea of injecting dry fly ash into the mine but expressed reservations about whether it would work and what would happen to the fly ash once it was down in the mine. An extended discussion then ensued, during the course of which Heavilon, Jones, and Thomas discussed surface subsidence, the lateral travel of fly ash in a mine, the angle of repose of the fly ash, the size and carbon content of the fly ash, the ability to inject fly ash into a mine filled with water, suitable injection pressures, and the bulking of fly ash. Thereafter, additional meetings were held prior to the demonstration on July 19,1967. Jones conducted a test in which fly ash was injected under water, and satisfactorily demonstrated that they could pneumatically inject fly ash into a water-filled mine.

21. The lateral travel and angle of repose of fly ash is pertinent to whether a barrier is formed and the thickness of that barrier. The bulking characteristic is a consideration in the structural support that such a barrier would provide for preventing surface subsidence. The carbon content is determinative of combustibility and the size of the fly ash, as well as the injection pressures, are considerations in the ability of fly ash to penetrate cracks and crevices.

22. Magnuson selected as the site for the test the mine-fire control project in the city of Monessen, Pennsylvania, in which a barrier had been flushed around the fire by conventional means, and in which a series of cased boreholes for monitoring the effectiveness of the barrier had been placed on the cold side of the barrier. While the conventional flushing boreholes were on approximately 10-foot centers, the inspection boreholes were on approximately 40-foot to 50-foot centers.

23. (a) Magnuson met Heavilon on the morning of July 17, 1967, and drove to the Monessen site. Heavilon’s purpose in viewing the site was to see if there would be any difficulty in getting the equipment in or out, to make sure the casing and adapter were ready, and to go through a dry rim. At that time, Heavilon was told by Magnuson that he could use one of the inspection casings for injecting fly ash into the mine and it was determined that the test would be run on July 19th.

(b) On Tuesday, July 18, Heavilon and Barton Thomas met with their truckdriver and instructed him on the procedures to be used. Barton Thomas and Heavilon visited the Monessen site together and went through the procedures they were going to follow the next day. They decided that Thomas would stay next to the truck and give the driver instructions while Heavilon would position himself at the other end of the hose at the borehole.

24. (a) On the morning of July 19, the experiment was conducted at the Monessen, Pennsylvania mine. A bulk tanker was parked near one of the boreholes and the fly ash was pumped out of the tanker and into the mine. Both Heavilon and Magnuson were surprised at the ease with which the tanker was able to unload the fly ash without encountering any problems. After the first tanker was emptied, plaintiff, on its own initiative, supplied five additional tankers, with a total of 125 tons of fly ash, all from boiler 33 of the West Penn powerplant, being injected. Fly-ash discharge was visible from other boreholes that had been drilled into the mine cavity and which were up to 50 feet away from the injection hole. All those who were present considered the demonstration to be a success; however, Magnuson at that time drew no conclusions from the test as to what had in fact happened to the fly ash in the mine.

(b) After a while, plaintiffs asked if they could inject some fly ash into a borehole that was directly over the fire. At first Magnuson was concerned about putting air on the fire but finally allowed injection into this so-called “hot hole.” A thermocouple in the hot hole showed a temperature of 290° F. at the start of the injection; it fell to 110° F. after injection.

(c) During the demonstration, plaintiff had control over the operation of the truck and the apparatus on the truck while Magnuson had control over the site itself and the selection of the boreholes through which the fly ash was injected. The type of fly ash used was selected by plaintiff, as was the rate of injection and the ratio of air to fly ash. The instruments, such as thermocouples, available at the site, were supplied by Magnuson.

(d) Plaintiff was never reimbursed or paid in any way for its services, personnel, equipment, or fly ash supplied at Monessen, nor has plaintiff ever received or entered into any contract with defendant in which it received money for development or use of the patented process. The major portion of the expense involved in the demonstration was borne by plaintiff; defendant’s only expenditure was in providing a fitting to attach the hose to the pipe in the borehole.

25. On July 20,1967, Magnuson arranged for a meeting to be held on July 28 with state and local officials to discuss the Lloydsville fire-control project. By July 28, a report evaluating the Monessen experiment had been prepared under Magnuson’s supervision. Calculations made in the preparation of that report indicated that Magnuson’s concern about using air as the injecting medium was unfounded. At the meeting on July 28, it was agreed to change the specification for the Lloydsville fire-control project to call for pneumatic injection of dry fly ash. At that time, it was contemplated that the carbon content of the fly ash would be not over 6% and that 85% of the material would pass through a 200-mesh screen.

Subsequently, and upon request from Magnuson’s office, Heavilon made recommendations regarding the type of equipment and its operation to include in the revised specification. Heavilon also recommended that the fly ash meet ASTM-C-350 in order to assure a particular fineness and suggested a maximum allowable carbon content of 8%.

26. By letter dated July 31,1967, Barton Thomas disclosed the subject of the patent in suit to his patent attorneys. That disclosure explained the value of the proposal, both for mine-fire control and surface-subsidence prevention. Among the information contained in the description was the low-carbon content of fly ash, its fineness (75% passing a 325-mesh screen) and consequent ability to fill small cracks, its fluidity, the ability of air to carry the ash laterally over substantial distances, the building up of a barrier both over and around the fire, and the structural support the barrier would provide for the surface.

27. By August 11,1967, Magnuson had completed revising the Lloydsville specification. Heavilon’s recommendations regarding the equipment were incorporated in the specification, as was the recommendation as to carbon content. The size range of the fly ash was specified as 90% through a 50-mesh screen and 75% through a 325-mesh screen. Both fly ash from boiler 33 of the West Penn powerplant and fly ash, meeting ASTM-C-350, would fall within that size range. The 90% limitation was a recommendation of Gerard Garnbs.

28. Plaintiff received a copy of the revised Lloydsville specification on or about August 11, 1967, and submitted a bid but was unsuccessful. Although bids were opened on September 6, 1967, award of the contract to the winning bidder was delayed until December 1,1967. Work at Lloyds-ville commenced on December 5, 1967, and the project was successfully completed on June 18,1968.

29. On September 20, 1967, a date prior to the scheduled commencement of the Lloydsville work, a conference, initiated by Magnuson, was held at the Bureau’s experimental mine at Bruceton, Pennsylvania, to set up a test program to evaluate the pneumatic injection of dry fly ash as a mine-fire control technique. One purpose of these tests was to provide data for the proposed Lloydsville project. Plaintiff was not invited to this conference.

Using fly ash obtained from the West Penn powerplant, tests were conducted in October and November, 1967, by a chemical research engineer, Edwin Murphy, employed by the Bureau of Mines. These tests were highly successful and it was at this point that Magnuson knew that this would be an excellent method of fire control.

Among the things established by these tests were:

a) Contrary to expectations, no significant portion of the fine fly ash dissipated itself as dust.

b) The fly-ash barrier, instead of settling as expected, absorbed moisture and actually swelled a little.

c) Dry fly ash has a low angle of repose and piles up at a much flatter angle, making a wider, more effective 'barrier.

d) The angle of repose was not so low that roofing was prevented.

e) Pneumatically injected fly ash completely permeates rubble piles.

f) After the pile of fly ash reached the roof, the air pressure under which the fly ash was injected caused the fly ash to move laterally to expand the roofed area over a substantial distance all around the borehole. This resulted in a barrier that was of several feet in thickness at the roof.

Murphy had also conducted the experiments reported in SI 6453 (finding 8) in which mineral wool was pneumatically injected. He found that the pneumatic injection of dry fly ash was far superior to the techniques he had earlier investigated.

30. The evidence is that Magnuson perceived the claimed process in stages. Prior to the demonstration, Magnuson believed that injection of dry fly ash would result in plugging the borehole and that the use of air would feed the fire like a forge. The demonstration satisfied him that dry fly ash could be pneumatically injected without plugging. Calculations made subsequent to the demonstration indicated that the use of air would not be a problem. Both prior and subsequent to the demonstration, Magnuson was unaware of the angle of repose of aerated fly ash. Both prior and subsequent to the demonstration, Magnuson formed no conclusions as to what was happening to the fly ash in the mine cavity. Although Magnuson issued the Lloydsville specification in August 1967, it was not until the Bureau experiments in October 1967 that Magnuson was satisfied that the powdery fly ash would not simply dissipate and would, in fact, form a satisfactory barrier. It was also not until after these experiments that Magnuson realized that the fly ash would penetrate rubble piles to block the flow of air and that the fly-ash barrier would provide subterranean support for the surface.

31. (a) The patent application was executed by the three applicants on September 18, 1967, and filed in the Patent Office on September 20,1967.

(b) The claims were allowed by the Patent Office after an interview with the examiner and the presentation of an amendment submitting arguments regarding the patenta-bility of the claims. These arguments included the assertion that fly ash, when used in the claimed method, would penetrate and block small cracks and crevices through which air would otherwise be supplied to the fire. Coextensive with this assertion, the limitation regarding fly-ash size was included in the claim to define a fly ash that would be of sufficiently small size to achieve that desirable end result. Neither the specification nor the arguments presented during prosecution indicate that the size of the fly ash must be exactly within the specified range. Nothing in the file wrapper indicates that the examiner was misled regarding the fly-ash size.

(c) Applicants’ remarks in the amendment, filed August 13, 1968, regarding the Lloydsville contract, are ambiguous in that it is unclear whether applicants were asserting that they were the successful bidder on that project. To the extent that they were so asserting, that assertion was incorrect. However, the identity of the successful bidder was wholly immaterial to the argument being presented, which was that the claimed method was proposed for and used at Lloydsville. That argument was entirely correct to the best of applicants’ knowledge.

(d) Although claim 1 does not expressly specify the angle of repose of the fly ash, aerated fly ash of the size specified in the claim would have an angle of repose of 8° to 10°.

32. The process of claim 1 differs from the pertinent prior art in the following respects:

1. The use of dry fly ash in controlling mine fires.

2. The injection of dry fly ash through a borehole into an underground mine cavity.

3. Injection of dry fly ash pneumatically.

4. Tbe use of air, itself a source of additional oxygen, as the medium for injecting the fly ash into the mine.

5. Injecting fine fly ash, with sufficient volume and pressure of air, to carry the fine particles into the cracks and voids in the mine.

6. The use of a dry powdery material having a low angle of repose either to form a barrier in a mine cavity or to provide subterranean support to prevent surface subsidence.

33. (a) A review of the patents cited by the Patent Office during the prosecution of the patent application has not disclosed any error in the Patent Office’s decision; specific findings as to each file wrapper reference, defendant having proposed none, is deemed unnecessary.

(b) The Lloydsville contract specification, published in mid-August 1967, is not prior art. A demonstration by plaintiff, using fly ash falling within the size range specified in the claims, took place prior to the drafting of that specification. The Lloydsville specification was drafted only after, and as a direct result of, that successful demonstration. Prior to August 1967, the inventors had determined that the fly ash should be of a size that 75% would pass a 325-mesh screen and that it, preferably, should meet ASTM-C-350. Fly ash, meeting that specification, would necessarily be of a size such that 90% would pass a 50-mesh screen.

34. (a) Bureau of Mines Report of Investigation 4808, dated October 1951, describes an underground coal gasification experiment during 1949-50, at {Jorgas, Alabama. The object of the experiment was to obtain energy in the form of gas from underground coal by igniting a coal seam in which some passages had been mined and blowing air in contact with the burning coal face. Because the mined passages were so large that the gasifying air blown into the-coalbed did not have sufficient direct contact with the coal to obtain good coal gasification, solid granular material was fluidized and injected by air down the borehole into the mine cavity until refusal, in order to fill the same and thus make the gasi-fying oxygen pass over the coal surface to react therewith. A sand barrier, which was formed by fluidizing sand and injecting the same down the borehole, was used to accomplish this result.

(b) Injection was accomplished by placing a pipe down a borehole into the mine cavity until it was about 1 foot above the bottom. Sand was then injected until the pipe plugged. The pipe was then raised and the process was continued until a barrier had been formed. A number of problems were encountered with the pipe plugging.

(c) When the gasification project was terminated, the underground fire was extinguished by pumping water into the underground cavity at a rate of 60 gallons per minute for 8 weeks to reduce the temperature from 1,000° F. to 220° F. This was a complete inundation of the fire with water. The Gorgas site was on the grounds of the Alabama Power Company which had a powerplant and fly ash very close to the project site. However, fly ash was not considered for extinguishing the fire.

35. The Schmidt et al patent, No. 2,710,232, was an outgrowth of the coal gasification project. (Finding 34.) The patent relates to a method of filling cavities with granular solids and, more particularly, to filling mined-out or burned-out cavities in an underground gasification mine with solid material. The only granular solids specifically mentioned are sand and earth. There is no mention of fly ash. The patent-states that if the particles are too large, difficulties occasioned by excessively high fluidization velocities are encountered and, on the other hand, if the particles are too small, it is difficult to maintain a uniformly fluidized condition. The patent also warns that excessively large amounts of air give rise to excessive dispersion of the sand. Additional listed uses of the process include filling fissures and cracks in walls and floors, filling mold cavities with granular material, lining furnace walls with granular refractory material, and filling mined-out areas to prevent subsidence. The patent contains no suggestion that the described process might have utility in controlling or extinguishing mine fires.

36. (a) The Anderson et al patent, No. 3,152,842, discloses a pneumatic bulk tanker, such as those that are commercially available and commonly used to transport fly ash. It is directed primarily to apparatus and gives little indication of potential uses for the materials that the apparatus transports.

(b) Tankers of this type aerate the material in the tank to render it flowable. The aerated material then flows into a discharge line where additional air is supplied to discharge the material. By various adjustments, the tanker can be operated to discharge the material under various conditions ranging from a pressurized discharge, in which the material would issue from the hose as a cloud of dust, to, as in the case of fly ash, a stream of material having properties similar to a stream of water.

37. The pertinent art is the field of fire control in inactive or abandoned coal mines. The field is an old one, with those of ordinary skill possessing substantial experience in mine-fire control work. The mine-fire control group of the U.S. Bureau of Mines works with the states in controlling abandoned mine fires. Research in this field is regularly conducted by the Bureau and the Bureau has an experimental mine it uses to aid its research. Many of the Bureau personnel are trained mining engineers possessing a high degree of experience, skill, and expertise in this field. In view of the Bureau’s active role in the control of fires in abandoned mines, its field personnel, together with those in corresponding positions at the state level, are representative of those ordinarily skilled in this art.

38. (a) On or about July 10, 1968, Magnuson submitted an invention report covering the pneumatic injection of dry fly ash to the Department of the Interior. Under section Y.A. 1(a) of that report, Magnuson asserted a conception in June 1967; under section V.A. 1(b) of that report, he stated that he first communicated the concept to others in “July 1967 prior to July 19 test,” a time subsequent to his meeting with Heavilon.

(b) By letter of July 18, 1968, the Assistant Solicitor, Branch of Patents, Department of the Interior, informed Magnuson that his disclosure was probably patentable and advised that a patent application would be prepared. In reaching his opinion, the Assistant Solicitor had made a prior art search and was aware of Schmidt et al Patent No. 2,710,232, Bulletin 590 (describing the prior art techniques discussed in finding 8), and Bureau publication RI 6453. The application was filed on September 9,1968.

(c) In an amendment dated April 25, 1969, Magnuson inserted in his application copies of claims 1-5 from the patent in suit, requesting institution of an interference. No interference was declared, the examiner holding that these claims were barred to Magnuson by reason of a publication more than 1 year prior to Magnuson’s filing date. Thereafter, Magnuson canceled those claims from his application and ultimately was granted patent No. 3,500,934, on March 17, 1970. The claims of that patent are limited to a method of pneumatically injecting an admixture of fly ash and either cement or swelling clays.

39. The patented method has been widely acclaimed by those in the mine-fire control field. It has received substantial publicity in the coal industry, based on interviews with Bureau of Mines personnel. Magnuson, in an address to the Annual Meeting, Coal Mining Institute of America, in 1968, described the method as “an important new tool for combating mine fires” and one having “great social benefit in addition to being effective and practical.”

In his invention report to the Department of the Interior in July 1968, Magnuson described the method as having these advantages over the prior art techniques:

1. The material forms an impervious seal which is tight against the roof of the cavity.
2. The material does not shrink; in fact, its absorbs water and expands.
3. The process uses a waste material which is a disposal problem to the power companies.
4. The process does not use water which must be purchased or pumped and the use of which requires winter shutdown of operations.
5. The fly ash penetrates crevices and rubble more readily because of the fineness of the material and the air pressures used during injection.
6. More material per borehole can be injected. (Tests have shown an average of 50 tons per borehole compared to 7 to 20 tons per borehole with conventional flushing.)
7. Less drilling is required to inject a given amount of material.
8. The pneumatic injection is accomplished using commercially available trucks which can be obtained through competitive bidding.

40. The specification for the Monongahela City Mine Fire Control Project No. 20 provided:

10. Description of Operations. * * * The operation will consist of dry pressure injection at locations in the project area as designated by the Contracting Officer. * * *
11. Plan of Operations. * * *
$ $ $ * $
Stage 4 — Drilling and casing boreholes. Boreholes of 6-inch diameter shall be drilled from the surface into the mine openings. * * * These boreholes will be drilled for the purpose of dry pressure injections of a fly ash-air mixture into the underground mine voids. * * *
‡ ‡ ‡
Stage 5 — Dry pressure injection. A fly ash-air mixture shall be introduced into the mine voids by bulk pneumatic trailer tankers discharging through the casings installed in boreholes as a part of stage 4 so as to fill the voids with incombustible material. The dry pressure injection shall be carried out at pressures ranging from nearly 0 to 15 p.s.i.
* # * * %
13. Description of Required Equipment, Services, and Materials. * * *
H* if: $ Hs %
Item 10 — Loading, transportation, and discharge of fly ash. The work outlined under stage 5 of the plan of operations, and other work as designated by the Contracting Officer, will require the services of 'bulk pneumatic trailer tankers. * * * The tractor-trailer rigs must be capable of being loaded with dry fly ash at the Mitchell plant of the West Penn Power Company at New Eagle, Pa., transporting it to the project site, and discharging it into 4-inch casings through casing adapters equipped with 4-inch Kam-Lock couplings at line and tank pressures ranging from 0 to 15 p.s.i. * * * The fly ash will have a size distribution such that 90 percent will pass through a 50-mesh screen and 75 percent will pass through a 820-mesh screen. * * *

41. The fly ash used on this project was initially obtained from West Penn and later from the Elrama powerplant of the Duquesne Light Company. Fly ash from silo 33 at West Penn has a size distribution falling within the claimed ranges. There is no evidence regarding the physical specifications of the fly ash from Elrama.

The procedure followed at Monongahela City was the same as that employed earlier at Lloydsville. At Lloydsville, a mixture of air and fly ash of the claimed size was injected under pressure down boreholes to fill the mine shaft and form an airtight barrier which would prevent further subsidence of the surface. In addition to building a fly-ash barrier around the fire and filling the cracks and voids, fly ash was injected through boreholes drilled into the fire area itself to extinguish the fire.

Upon completion of the injection process, the boreholes were closed and sealed by filling them with dirt.

CONCLUSION

Upon the foregoing findings of fact, which are made a part of the judgment herein, the court concludes as a matter of law that claim 1 of U.S. Patent No. 3,421,587 is valid and infringed. Accordingly, plaintiff is entitled to recover reasonable and entire compensation for unauthorized use by defendant, and judgment is entered to that effect. The extent of liability will be determined in further proceedings pursuant to E-ule 131 (c) (2). 
      
       Accounting, If any, Ras been deferred to later proceedings.
     
      
       The responsibility of the Bureau of Mines is as stated in 30 U.S.C. §§ 551-58 (1984). A description of the techniques developed for fighting fires is contained in the findings.
     
      
       In 1965, only about 3% of the 20 million tons of fly ash produced was used commercially. Disposing of this waste product is a substantial problem, utility companies will frequently pay someone to dispose of it for them.
     
      
       The circumstances giving rise to the filing of that application are discussed, infra.
      
     
      
       Plaintiff has proposed no findings, and makes no argument, regarding infringement of claims 2 — 5. Accordingly, plaintiff’s claim for compensation is deemed to be restricted to claim 1. It is, therefore, unnecessary to consider the validity and infringement of claims 2-5.
     
      
       The Lloydsville project was completed prior to issuance of the patent and is not asserted as the basis for a claim for compensation.
     
      
       The very able presentations of counsel have been of great assistance in resolving what is a most difficult issue, involving as it does a determination of the state of mind of an individual at a particular time.
     
      
       Defendant’s witness Magnuson demonstrated a commendable appreciation for tills problem. He forthrightly acknowledged the difficulty of separating in his mind what were the actual facts from what he now, years later, would assume the facts to have been.
     
      
       In his invention disclosure report submitted to the Department of the Interior, Magnuson stated that he first communicated the idea to others in July 1967, a date subsequent to his meeting with Heavilon.
     
      
       Although a party may plead alternatively and inconsistently, the multiple theories of inventorship advanced by defendant in this case tend to confirm the lack of clear and convincing evidence in the record to support any one theory.
     
      
       The defense of unenforceability, premised on fraud on the Patent Office, has not been established, Layne-New York Co. v. Allied Asphalt Co., supra; Mueller Brass Co. v. Reading Industries, supra, and merits no comment. See finding 31.
     