H.J. Heinen, G.E. McClelland and R.E. Lindstrom v Pancontinental Mining Ltd and Eight Others

[1986] APO 12

In the Matter of the Patents Act 1952

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In the Matter of Application No. 521033 for a Patent by H.J. HEINEN, G.E. McCLELLAND AND R.E. LINDSTROM

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In the Matter of Section 59 Opposition thereto by ‑

(1)  PANCONTINENTAL MINING LTD.
  (2)  WESTERN MINING CORPORATION AND CENTRAL
  NORSEMAN GOLD CORP. LTD.
  (3)  WHIM CREEK CONSOLIDATED NL
  (4)  THE BROKEN HILL PTY. COMPANY LTD.
  (5)  NEWMONT HOLDINGS PTY. LTD.
  (6)  HOMESTAKE AUSTRALIA LTD.
  (7)  RENISON LTD.
  (8)  PLACER EXPLORATION LTD.
  (9)  THE SHELL COMPANY OF AUSTRALIA.

DECISION OF A SUPERVISING EXAMINER OF PATENTS:
Background
         Patent application 521933 entitled "LEACHING GOLD‑SILVER ORES" was lodged on 11 April, 1980 claiming priority under the Convention from two applications lodged in the United States of America on 13 April, 1979.  Acceptance of the application was notified in the Official Journal dated 6 May, 1982.
         Notices of opposition under s.59 were lodged by:
    (1)  PANCONTINENTAL MINING LTD. on 29.7.82
    (2)  WESTERN MINING CORPORATION AND CENTRAL NORSEMAN GOLD CORP. LTD.
         on 3.8.82
    (3)  WHIM CREEK CONSOLIDATED NL on 3.8.82
    (4)  THE BROKEN HILL PTY. COMPANY LTD. on 4.8.82
    (5)  NEWMONT HOLDINGS PTY. LTD. on 5.8.82

(6)  HOMESTAKE AUSTRALIA LTD. on 5.8.82
    (7)  RENISON LTD. on 6.8.82
    (8)  PLACER EXPLORATION LTD. on 6.8.82
    (9)  THE SHELL COMPANY OF AUSTRALIA on 6.8.82.
         The service of evidence was completed by 21 December, 1984 and the matter was heard in Canberra from 29 April, 1985 to 3 May, 1985.  The opponents were represented by Dr. J.McL. Emmerson of Counsel instructed by Mr. C.J. Oberin, patent attorney of Phillips, Ormonde & Fitzpatrick, assisted by Mr. J.C. Quinn and Mr. R.J. Robinson of Newmont Holdings.
         The applicants were represented by Mr. K.R. Handley, Q.C., Mr. F.L. Harrison, Q.C., and Mr. B. Clark of Counsel instructed by Mr. G.T. Down, solicitor, of The Northern Queensland Company Ltd., assisted by Dr. R.P. Henry. The Northern Queensland Company Ltd. (TNQCL) is the exclusive licensee of the applicants, and is responsible for prosecution of this application.
The Specification
         The invention relates to percolation leaching, particularly heap leaching of low‑grade gold or silver ores, tailing or waste.  Many such materials are not amenable to existing percolation leaching processes because of the presence of excessive amounts of clays or of fines which impede the uniform flow of leach solution through feed beds, causing channeling and reducing precious metal recovery.  In the mineral processing field slimes are generally defined as the fraction of an ore that is too fine to be commercially exploited by processes developed for the coarser size fractions; frequently slimes are considered to be particles less than 50 microns in diameter.  Because prevailing technology is inadequate to handle the slime problem in heap leach cyanidation, many of the low‑grade clayey gold and silver deposits cannot be exploited.
         According to the invention, these problems can be overcome if the feed material is pretreated with a binding agent and liquid to produce porous agglomerates which will withstand percolation leaching without substantial disintegration.
         In accordance with one aspect of the invention the efficiency of percolation leaching processes for recovery of gold and/or silver can be substantially improved by initial pretreatment of the feed with a binding agent and water to agglomerate fines contained in the feed, followed by aging of the thus‑treated feed.  The pretreated feed can then be subjected to conventional percolation leaching techniques to recover gold and/or silver values.  The efficiency of percolation leaching can be further improved by pretreatment of the feed with a binding agent and aqueous cyanide solution, which agglomerates the fines contained in the feed as well as forming soluble cyanides of the gold or silver values.  Essentially all of the leachable precious metal content of the ore is removed in about ten hours or less using a leach solution in which the free cyanide and alkali content is very low if the crushed ore or finely divided feed materal and binding agent are mixed with an alkaline cyanide solution considerably more concentrated than that conventionally employed.  In this case the wetted ore is aged for a time sufficient for agglomeration of the fines in the ore and also for substantially complete reaction of the cyanide with gold or silver before leaching the soluble gold or silver cyanides.  In some cases it is not even necessary to add protective alkali to the cyanide solution, hydrolysis of the sodium cyanide being sufficient to raise the pH to the proper level.
         The pretreatment of the feed increases its porosity and permeability, thus enhancing the percolation flow of leach solutions through beds or heaps of the gold or silver containing feed.  Both the speed and extraction efficiency of the leaching process is thereby substantially improved.
         Burnt lime, i.e. calcium oxide and type II Portland cement have been found to be particularly effective as binding agents although other binding agents such as magnesia or dolomite may also be used.  Particular combinations of binding agents may also be effective for treatment of specific feed materials.
         Flocculating agents, including lime have been widely employed in thickening and dewatering applications but the primary purpose of such procedures is the production of briquettes or pellets that do not spall during thermal induration.  In contrast, the objective of the present invention is conversion of fines in feed materials to porous agglomerates having sufficient green strength to withstand percolation leaching.  Lime is also frequently used to provide protective alkalinity in conventional heap leaching.  However, its use in this manner has little beneficial effect on the percolation flow through ore beds.  Optimum amounts of binding agent and cyanide solution will vary with the type of feed and specific binding agent and cyanide solution employed.  Suitable amounts of binding agent will usually be in the range of about 5 to 15 pounds per ton of feed with the amount of cyanide solution generally being in the range of about 8 to 15 weight percent based on the amount of feed.  By proper control of the quantity of binding agent and solution, only the fines are agglomerated, leaving the coarser fragments of the feed material relatively unaffected.  This results in a granular, popcorn‑like product of substantially increased porosity and permeability.
         The cyanide solution will generally consist of aqueous sodium cyanide, although solutions of calcium or potassium cyanide may also be employed.  Sodium hydroxide, lime or sodium carbonate is employed in the cyanide solution in an amount sufficient to provide protective alkalinity.
         The cyanide solution may be added and admixed with the feed‑binding agent mixture by any conventional means such as a pelletiser or balling machine.  Agglomeration of fines in the resulting admixture is also accomplished by conventional mechanical means such as the use of a rotating disk pelletizer or a balling machine to produce agglomerates, pellets or balls from the fines.  Admixture of the feed‑binding agent mixture with the solution and agglomeration may be effected simultaneously.  Other methods for preparation of the wetted feed‑binding agent mixture such as spraying a slurry of the binding agent onto the dry feed may also be used.
         The specification continues:

"The resulting material is then aged or cured, without drying, at ambient conditions for a period of time sufficient to cause the agglomerates to set up and develop sufficient green strength to withstand further wetting without disintegration, as well as effecting reaction of the cyanide solution with gold or silver values.  Although optimum aging time may also vary considerably with specific feed material and binding agent, suitable times will usually fall within the range of about 5 to 72 hours.  Use of appropriate accelerators, particularly where the binding agent is cement, may, however, reduce the required aging considerably.  Again, however, the time of aging has been found to be important to achievement of best results and optimum aging time should, therefore, be determined experimentally in each case."

Leaching of the pre‑treated feed to extract gold or silver values is accomplished by conventional percolation leaching procedures, such as heap leaching or vat leaching.  The leach solution may consist of water or a dilute cyanide solution.  The preferred initial leachant is water which after recovery of the gold or silver values by conventional means results in a dilute cyanide leach solution which can be recycled.
         In the first preferred embodiment percolation leach tests were performed on two gold ore samples in a plexiglass column.  The three tests consisted of a test with no pre‑treatment, a test employing agglomeration of fines in the feed with a combination of type II Portland Cement and water and a test employing agglomeration of fines in the feed with type II Portland Cement and aqueous sodium cyanide.  The results indicated that agglomeration of the fines in the gold ore sample with small amounts of clayey and fine material was not essential for an adequate percolation rate although the rate was improved by agglomeration.  However pretreatment with the combination of cement and cyanide solution resulted in substantially reduced leaching time.
         Where, however, the feed consisted of a gold ore sample containing significant amounts of clayey and fine material, agglomeration of fines was essential for the achievement of adequate percolation rates.  Moreover the leaching time was substantially reduced particularly when the combination of cement and cyanide solution was employed in pretreatment.
         Similar series of leaching tests performed  on a clayey silver ore showed similar results to those described above.
         The claims defining the invention are as follows:

1.A process for percolation leaching of gold and/or silver values from a feed material comprising or consisting of ores, tailings or wastes which process comprises the steps of:

(1)admixing the feed material with 0.25 to 0.75 weight percent of a binding agent and 8 to 16 weight percent of water,

(2)mechanically manipulating the admixture to effect agglomeration of fines in the feed material,

(3)aging the admixture at ambient conditions for a time sufficient to provide the resulting porous agglomerates with strength sufficient to withstand further wetting without substantial disintegration, and

(4)subjecting the aged admixture to percolation leaching to selectively leach gold and/or silver values therefrom.

2.A process for percolation leaching of gold and/or silver values from a feed material comprising or consisting of ores, tailings or wastes which process comprises the steps of:

(1)admixing the feed material with 0.25 to 0.75 weight percent of a binding agent and 8 to 16 weight percent of an aqueous cyanide solution,

(2)mechanically manipulating the admixture to effect agglomeration of fines in the feed material,

(3)aging the admixture at ambient conditions for a time sufficient to provide the resulting porous agglomerates with strength sufficient to withstand further wetting without substantial disintegration and for substantial reaction of the cyanide with gold and/or silver values in the food (sic) material, and

(4)subjecting the aged admixture to percolation leaching with water or cyanide solution, whereby gold and/or silver is selectively leached.

3.A process as claimed in claim 1 or claim 2, in which the binding agent is portland cement, lime, calcium aluminate cement, magnesia, dolomite, an inorganic silicate, an organic long chain polymer, of a mixture of any such materials.

4.A process as claimed in any preceding claim, in which the feed material is a low‑grade glayey gold or silver ore, tailings or mine waste material.

5.A process as claimed in any preceding claim, in which steps (1) and (2) are carried out simultaneously.

6.A process as claimed in claim 2 or claim 3 when appended to claim 2, in which the aqueous cyanide solution referred to in step (1) consists of an 0.05 to 0.2 molar solution of sodium cyanide.

7.A process as claimed in any preceding claim, in which the aging time is from 5 to 72 hours.

8.A process as claimed in any preceding claim, in which the percolation leaching consists of heap, vat or flood leaching.

9.A process for the percolation leaching of gold and/or silver values from a feed material comprising or consisting of ores, tailings or wastes, which process comprises treating the feed material with a binding agent and an amount of water sufficient to wet or dampen, but not to inundate, the feed material in order to form porous agglomerates, aging the agglomerated feed so that the agglomerates will withstand percolation leaching without substantial disintegration, and subjecting the aged porous agglomerates to percolation leaching to leach the gold and/or silver values therefrom.

10. A process as claimed in claim 9, in which the water contains a soluble cyanide.

11. A process as claimed in claim 9 or claim 10, in which the treating of the feed material to form the porous agglomerates also involves the step of mechanical manipulation.

12. A process as claimed in any one of claims 9 to 11, in which the binding agent is portland cement.

13. A process as claimed in any one of claims 9 to 12, in which the percolation leaching is carried out with a cyanide solution.

14. A process for the percolation leaching of gold and/or silver values from a feed material comprising or consisting of ores, tailings or wastes, which process comprises admixing the feed material with a binding agent and an amount of water sufficient to wet or dampen, but not to inundate, the feed material mechanically manipulating the admixture to effect agglomeration of fines in the feed material, aging the admixture at ambient conditions for a time sufficient to provide the resulting porous agglomerates with strength sufficient to withstand further wetting without substantial disintegration, and subjecting the aged admixture to percolation leaching to extract the gold and/or silver values therefrom.

15. A process for the percolation leaching of gold and/or silver values from a feed material comprising or consisting of fines, which process comprises the steps of admixing the feed material with a binding agent and with an amount of water sufficient to wet or dampen, but not to inundate, the feed material, thereby forming porous agglomerates comprising or consisting of fines contained in the feed material, aging the agglomerates for a time sufficient to enable them to withstand percolation leaching without substantial disintegration, and subjecting the aged agglomerates to percolation leaching to leach the gold and/or silver values therefrom.

16. A process as claimed in claim 14 or claim 15, in which the water contains a soluble cyanide.

17. A process as claimed in any one of claims 14 to 16, in which the binding agent is portland cement.

18. A process as claimed in claim 16, in which the percolation leaching is carried out with water or cyanide solution.

19. A process for the percolation leaching of gold and/or silver values from a feed material comprising or consisting of ores, tailings or wastes, which process comprises treating the feed material with a binding agent and water to produce a granular product comprising or consisting of porous agglomerates, aging the porous agglomerates for a time sufficient to provide them with strength sufficient to withstand percolation leaching without substantial disintegration and subjecting the granular product thus formed to percolation leaching to leach the gold and/or silver values therefrom.

20. A process as claimed in claim 19, in which the water contains a soluble cyanide.

21. A process as claimed in claim 19 or claim 20, in which the treating of the feed material also involves admixing of the feed material with the binding agent and the liquid and manipulating the admixture to effect agglomeration of fines in the feed material.

22. A process as claimed in claim 20, in which the cyanide is sodium cyanide, potassium cyanide or calcium cyanide.

23. A process as claimed in claim 21, in which the feed material is mixed with 0.25 to 0.75 weight percent of binding agent.

24. A process as claimed in claim 20 or claim 22, in which the feed material is mixed with 8 to 16 weight percent of aqueous cyanide solution.

25. A process as claimed in claim 24, in which the aqueous cyanide solution consists of 0.05 to 0.2 molar solution of sodium cyanide.

26. A process as claimed in claim 21, in which the mixing of the feed material, binding agent and liquid takes place in a mechanical agitating device.

27. A process as claimed in claim 26, in which the said device is a pelletizer or balling machine.

28. A process as claimed in any one of claims 9 to 27, in which the aging time is from 5 to 72 hours.

Section 40
         In my view, there are a number of serious defects in the claims considered as definitions of an invention which purportedly opens up the technology of percolation leaching.  The specification has represented the invention as the perception of dealing with "low‑grade gold or silver ores, tailing or wastes ... many of which are not amenable to existing percolation leaching processes because of the presence of excessive amounts of clays, or of fines ...".
         As a process claim is characterised in particular by the "entity" to which the process steps are applied, one would expect the feed material of the claims of this application to be of that category for which the invention has provided a needed solution.  This is not so in many of the claims.  As conceded by Mr. Handley at the hearing, a feed that consists of, or comprises ore may have substantially no content of fines.  This comment is also applicable to the terms "tailing" and "wastes", although this would be a more unusual situation.
         One of the characteristic steps of the process of the invention is to admix the feed material with a binding agent and a specified amount of liquid, for example, water.  Such a step is defined, for instance, in item (1) of claim 1.  Unfortunately, that claim, and others, do not specify that the percentage of water (or liquid) added is based on feed dry weight, as I presume it must be.  If this were not so, the initial feed might have sufficient water content inherently (e.g. as mined or as a result of exposure to the environment) to obviate the necessity for the liquid addition step, or at least to allow of quantitative modification of that step.  Consequently, these claims are not clear definitions of the invention.
         Further to the preceding two problems, neither the specification nor the claims adequately describe and define weight percent additions of binding agent and liquid to the feed material.  Surely, if this were to be properly done, such additions should be related to the amounts and sizing ranges of fines present in the feed.  Despite this, I consider that the description is adequate for the man skilled in the art to make the relevant additions, if only initially by trial or experiment; in fact it would be impossible to specify quantitative additions in such a way that it would be possible to immediately determine accurately the best ranges thereof for any and all tailings dumps.  Naturally, this would depend on the nature of the ore from which the tailings were derived, and in the extractive industry, such trials and experiments are normal.  However, where the claims refer to specific quantities of binding agents and water (or liquid) additive, these quantities are meaningless owing to the unspecified nature of the ore, and really, a full characterization of the results sought would be the only solution.

         Next I come to the step of aging.  This is a step which is variously specified in the claims.  For example, claim 9 recites:

"aging the agglomerated feed so that the agglomerates will withstand percolation leaching";

and claim 1 recites:

"aging the admixture at ambient conditions for a time sufficient to provide the resulting porous agglomerate with strength sufficient to withstand further wetting without substantial disintegration."

As far as claim 9 is concerned, it is undoubtedly an essential feature that the agglomerates must be such as to withstand percolation leaching ‑ otherwise there is no invention.  However claim 1 and a number of other claims are not limited by this requirement.  In this respect they are not fairly based ‑ what meaning could be given to the expression "further wetting" as used in those claims is of little assistance, for if the mixture is "aged" at "ambient conditions", it may get wetter, drier, or remain the same, depending on those conditions; in any case, the "further wetting" is clearly not necessarily equivalent to wetting by percolation leach.  There is a further more serious defect in the definition of the aging step which I find to apply to all claims. That is, it is simply not specified in such a way as to define the invention which has been described ‑ see my comments above on "ambient conditions" and "further wetting".  In fact it would appear from the description at page 6 lines 26 et seq., that the aging is done without drying at ambient conditions.
         There remains one further point.  Claims 9 and 19 define a process

"which process comprises treating the feed material ... to form porous agglomerates."

Dr. Emmerson has suggested that the use of the word "treating" in that context causes the scope of the claims concerned to be indefinite, and he has pointed out that each of the other independent claims save claim 15 are restricted by the feature of "mechanically manipulating the admixture" to effect agglomeration of the fines.  I do not agree.  There are a number of ways of causing the admixture of feed material with binder and liquid to agglomerate ‑ mechanical manipulation is one such way.  I note also that the "treatment" step is applied to the feed material per se and includes the steps of binder and liquid addition.  I see no problem here.  Also, it is to be noted that claims appended to claims 9 and 19 include features of mechanical manipulation, correctly, as I see the latter as being a  subclass forming part of the broader "treatment" step.
         Claim 15 is in a separate class.  It merely recites:

"... admixing the feed material with a binding agent and an amount of water ... thereby forming porous agglomerates."

It seems to me that there is no step defined in this claim which would cause the agglomerates to form, otherwise the step of mechanically manipulating in claims 1, 2 et al would be superfluous.
The Evidence and Submissions
         I do not intend to summarise the evidence because of its extensiveness ‑ there are 871 folios including 70 exhibits, of which there are 34 different publications of a technical nature.  I will direct my attention to the independent claims whilst considering that evidence which I view as most relevant to whether the invention has been anticipated and/or whether it is obvious.
         At the hearing, the general thrusts of the submissions made by Mr. Handley and Dr. Emmerson were as follows: Mr. Handley, whilst conceding that each of the individual steps in the claims were part of common general knowledge, submitted that the present invention represented an inventive combination.  He also argued that much of the evidence filed by the opponents concerns the processing of mineral ore containing metals other than gold and/or silver, and whilst a process step might be known to be suitable for processing a particular metal ore it did not follow that the process was known to be suitable for processing metal ores in general, or gold and/or silver ores in particular.
Dr. Emmerson expressed the view that the claims did not define a patentable combination in the light of the documentary evidence and in any case because each of the independent claims defined a different process. He submitted that all the claims did define was the application of agglomeration leaching to a gold and/or silver ore, and he compared the present application to the "stainless steel cases" described in the Microcell case (Commissioner of Patents v. Microcell Ltd. 102 CLR 232 at pages 248 and 249).
         Where appropriate I will refer to the more detailed submissions in my following considerations.
Anticipation
Shepherd and Skinner Publication
         Exhibit REW‑13 which is entitled "Stabilizing Agglomerated Slimes for Cyanide Leaching" was published in Australia in 1937.  The paper describes the laboratory scale development of a method of agglomerating slimes by the formation of a cementing substance in the glomerules.  When the glomerules are stabilised in this way the necessity for incorporating coarse material with the slimes is eliminated, and the glomerules do not break down when flooded.
         Small scale tests are described in which the permeabilities of quartz samples are measured after treatment with lime, lime and carbon dioxide and lime and sodium carbonate.  Larger scale tests were performed with gold containing tailings ("Ashdown tailings") in order to determine if the precipitation of calcium carbonate in the glomerules would coat the mineral particles so that the values could not be dissolved.
         The tailings were mixed with hydrated lime in a dry state and then agglomerated with aqueous cyanide solution whilst carbon dioxide was passed into the mixture for a period of time.  Alternatively the lime/tailings mixture was agglomerated with aqueous cyanide containing sodium carbonate and the agglomerate allowed to stand for 1 hour.  In each case the agglomerate was percolation leached with an aqueous cyanide solution to recover the major portion of the gold values in 15 hours.
         Mr. Handley submitted that the document taught away from the present invention because the authors did not appreciate that less than 1% by weight of lime could be used as a binding agent itself and they proceeded to investigate more complex systems of binding agents.  He also argued that the process described in the document did not include an aging step when lime was used alone and the delay with the more complex system was to allow time for the reaction which produced calcium carbonate to take place.  In respect of this document Dr. Emmerson submitted that the fact that there was a chemical reaction between lime and carbon dioxide or sodium carbonate was irrelevant provided there was a binding agent present.  In fact he pointed out that both Portland Cement and burnt lime, which are given as examples of the binding agent in the present specification, would undergo chemical reaction with the aqueous solution which is used in the present invention.  Mr. Handley replied by stating that the claimed process used a binding agent, not two compounds which reacted together to form a binding agent, and he also pointed out that neither carbon dioxide nor sodium carbonate could be considered to be binding agents.
         One possible binding agent described in the specification is Portland Cement and exhibit RPH‑8 to Dr. Henry's affidavit, which was filed on behalf of the applicants, describes the reaction of this binding agent with water.  Thus in my opinion the term binding agent does not exclude an agent which undergoes reaction.  The description of the invention on page 4, lines 20 to 22 also refers to "particular combinations of these binding agents".
         The agglomerates in the claimed processes are aged for sufficient time to provide the resulting agglomerates with strength sufficient (in some claims) to withstand further wetting, or (in other claims) percolation leaching, without substantial disintegration; in yet other claims the agglomerates are provided with strength sufficient also for substantial reaction of the cyanide with gold and/or silver values in the feed material.  Thus the aging step in the present invention may be for the purpose of allowing chemical reactions to take place either to allow the agglomerate to gain strength or to allow the leachant to react with metal values.
         Therefore I consider that as far as the disclosure of Shepherd and Skinner goes, lime and carbon dioxide and lime and sodium carbonate lie within the scope of the term "binding agent" as it is used in the present claims, and that aging is taught, at least in the terms as claimed by Heinen et al.
         The proportion of aqueous cyanide solution which is used in the process described in the Shephard and Skinner publication falls within the range claimed in claim 2 but the proportion of binding agent which is described lies outside the claimed range.  However I consider that this difference would be easily found by the non‑inventive optimisation tests described by Mr. Wilmshurst.  Therefore I consider that claim 2 lacks novelty in view of this document.
         The small scale tests described by Shepherd and Skinner generally involved agglomeration of the material with water however agglomeration by use of aqueous cyanide leachant was described with respect to the Ashdown Tailings  tests.  Therefore I consider that this document prior publishes claims 1, 9, 14, 15 and 19.
         The small scale tests described in the Shepherd and Skinner publication, which do not involve extraction of gold and/or silver values from the feed material, also render the invention defined in the independent claims not novel.
Scrutton Publication
         Exhibit RJR‑4 is entitled "Occurrence and Treatment of Gold Ore at Bidi, Sarawak, Borneo" and was published in Australia in 1923.  This document describes the processing of ore which included both stoney ore and clayey ore containing up to 20% moisture.  The clayey ore was formed into balls by adding lime and allowing it to roll down a chute into a storage bin.  This produced balls which were firm enough to maintain their shape when charged into the leaching vat, but which are described as being coated with lime.  It was essential to have the right amount of moisture to attack the lime because if there was insufficient moisture the lime did not stick, however the lime was adsorbed if too much moisture was present.  The balls of clay were loaded over several hours into the leaching vats and the gold values were extracted over a period of 10 days.
         Mr. Handley submitted that the Scrutton document taught the aging of only part of the ore, namely the clayey ore, whereas the present specific‑
ation described aging of all of the feed material.  He also argued that the fact that the balls were coated with lime was the reason they maintained their integrity during leaching but he stated that it did not follow that the balls were of the same character as the porous agglomerates defined in the present claims.  Dr. Emmerson pointed out that the proportion of lime described in the Scrutton document fell within the range of binding agent defined in claims 1 and 2.
         Whilst I agree that the present specification teaches that all the feed material used in the present process should be aged I do not think that the specification teaches that all the products of a mine should be treated by the present process.  I also think that the clay balls described in the Scrutton document were porous because the gold values were extracted by a leaching process and I think the rolling of the mixture of clayey ore and lime down a sloping chute amounts to "treating" rather than "admixing" the two.  In fact the publication teaches that the balls were coated with lime as a result of treating the ore with lime.  I also note that no aqueous liquid was added to the mixture of feed material and lime.  Therefore I consider that the Scrutton document does not prior publish the claimed process.  However it does teach the uninventive skilled worker the importance of the moisture content and I think that the use of a binding agent with an aqueous liquid does not amount to an inventive difference from this prior art.  Therefore I consider that the Scrutton publication renders the process claimed in claims 1, 9 and 19 not novel.
Jensen Publication
         Exhibit RJR‑2 is entitled "Mining and Treatment of Gold Bearing Clayey Ores at Golden Ridges, New Guinea" and was published in Australia in 1958.  This document describes the extraction of the gold and silver values from clayey ore after an earlier method had failed.  The ore which was a sticky mixture of clay and stone had a moisture content of between 18 to 28% and was stored in a bin.  It was supplied from this bin to the leaching vat by a belt conveyor and lime was added with the felt feed.  The metal values were leached out with aqueous potassium cyanide over 11 days and the vat residue consisted of material whose size ranged from hand picked lump ore to a screen value of less than 80 (I.M.M. mesh).
         Mr. Handley submitted that this document did not teach agglomeration of the feed material and I agree with him.  Therefore I am satisfied that the Jensen document does not prior publish or render not novel the presently claimed invention.
Sullivan and Towne Publication
         Exhibit REW‑9 is entitled "Agglomeration and Leaching of Slimes and Other Finely Divided Ores" and was published in Australia in 1931.  This document describes agglomeration of slimes and finely divided ores, followed by percolation leaching tests.  The bulk of the tests relate to copper ores, but there is a clear disclosure of three tests on gold ores where after agglomeration, leaching was conducted with solutions of acidified iron salts.  The use of powdered marble as a binder is also disclosed.  Mr. Handley (referring to Dr. Henry's declaration) submitted that this document did not teach any aging step and that the difference between this document and what he described as "the technology of the patent application" were sufficient for Sullivan and Towne not to be an anticipation.  He also pointed out that the glomerules  produced were not able to maintain their integrity when flooded with leach solution.
         Dr. Emmerson (referring to Mr. Wilmshurst's first declaration) refuted Dr. Henry's argument and suggested that the agglomerates formed in the test work did withstand trickle leaching, but conceded that they failed under flood leaching conditions.  He pointed out that the moisture range disclosed in the document is wholly within the preferred moisture content range of the opposed specification (8‑12% cf. 8‑16%).  Dr. Emmerson stated that Sullivan and Towne also investigated the use of the leachant rather than just water to agglomerate the feed material.  I consider that Sullivan and Towne's publication does teach the use of a binder (the powdered marble) and the wording of the paper clearly envisages agglomerating gold ore, with the addition of "a solution to agglomerate the ore".
         As to the matter of aging the agglomerates, all that the claimed process requires is that the agglomerate have strength sufficient to withstand further wetting or percolation leaching without substantial disintegration.
         Since the glomerules produced by the tests described in Sullivan and Towne were in fact trickle leached successfully I consider that this criterion has been met.
         However the purpose of the leaching tests described in the Sullivan and Towne document was to investigage the effect of the ore on the iron salts in the leachant rather than to leach the gold values from the ore.  Therefore I consider that the Sullivan and Towne document does not prior publish the invention defined in the independent claims, but that the difference between the disclosure of this document and the invention claimed does not amount to novelty.
         This conclusion applies to claims 9, 14, 15 and 19.  As to the matter of binding agent, the proportion is not specified in the Sullivan and Towne document, but I consider the correct proportion would easily be found by non‑inventive optimisation tests and therefore I consider claim 1 also to be not novel.  Although the use of a leaching agent in binding the agglomerates together is disclosed in the document, no mention is made of proportions, or of using cyanide, therefore I consider that this document does not render claim 2 not novel.
The Pryor Publication
         Exhibit JRK‑9 and REW‑11 is entitled "Mineral Processing (Third Edition)" and was published in Australia in 1972.  This work is a standard textbook and was admitted by all parties to form part of the common general knowledge in Australia.  However I feel this publication goes into insufficient detail to anticipate any of the claims.
The Dorr and Bosqui Publication
         This document is an extract of a text entitled "Cyanidation and Concentration of Gold and Silver Ores" and was published in Australia in 1957.
         This text is a standard reference which all parties admitted constitutes part of the common general knowledge in Australia.  The extracts exhibited are a synopsis of the Scrutton document and a synopsis of the Shephard and Skinner document.
         The synopsis of the Scrutton document does not state that the clayey ore was formed into balls in the presence of lime nor is an aging step described.  Therefore this synopsis does not prior publish or render not novel the claimed invention.  The synopsis of the Shephard and Skinner document summarises twelve pages of the original in half a page without describing an aging step.  I do not see that this synopsis prior publishes the claimed invention or renders it not novel.
Obviousness
         The background against which obviousness must be judged is the state of the common general knowledge in Australia at the priority date of the claims (see the judgement of Aicken, J. in Minnesota Mining and Manufacturing Co. v. Biersdorf (Australia) Ltd. 199 CLR 253).
         I have observed earlier in this decision that much of the evidence in support concerns techniques of leaching and agglomerating ores of metals other than those of gold or silver.  Thus evidence is on file relating to ores of iron, nickel, uranium and copper.  The allegation has been made that transfer of information within the mining industry is continuous, not only in Australia, but world wide.  Consequently, in the light of common knowledge existing in the fields of the metals named above, the present invention must fail on the ground of obviousness.  I shall consider this matter first, before turning to the other arguments in support of this ground.
          Mr. Canterford, who works in the CSIRO Division of Mineral Chemistry declares that if he had been required to leach gold or silver from ores, tailings or wastes of low permeability he would:

"automatically have evaluated agglomeration of the fines as a method of improving permeability in view of my existing knowledge of the widespread and successful application of this technique within the mining field."

He also states that he was aware that percolation leaching was in use for the recovery of copper and he continues as follows:

"Knowledge of such operations and of percolation leaching in general is and has been in my experience since well before 1979 so wide‑spread among those interested in the field of mining including mining company employees, independent researchers and academics as to be part of the background experience and knowledge available to all such persons for applying to any problem that arises or has arisen in the course of extracting minerals from ores."

Mr. Kleeman who is a Senior Lecturer in the Department of Mining and Metallurgy at Queensland University, says that if he was confronted with any problem relating to the extraction of gold and/or silver by cyanidation which he was not able to solve from his own knowledge and experience he would refer to a textbook entitled "Cyanidation and Concentration of Gold and Silver Ores" by Dorr and Bosqui.  He also declares that:

"It is my view that it has been a common practice in Australia and elsewhere since well before April, 1979 to apply techniques first developed in relation to one metal ore to ores of other metals where comparable considerations apply.  For example techniques first developed for the cyanidation process for gold have subsequently been applied to uranium ore processing."

Mr. Wilmshurst, who is Technical Director of AMDEL, comments that if he had been faced with the permeability problem he would have looked at agglomeration as a possible solution as he did with "the Burra ore".  He also says that ore bodies vary from one another and on occasions, as at Burra, there may be significant variations within one ore body and therefore it is necessary to determine the optimum conditions for extracting the metal values.  He continues:

"Such optimization tests are and have been for many years and since well before 1979 carried out as a matter of routine by Amdel and, in my experience elsewhere within the mining industry, the work is and has been carried out as a matter of routine by ordinary skilled personnel without specific invention."

However Mr. Robinson, who is a Senior Metallurgist employed by Newmont Holdings, states that if he had been confronted with low permeability in the cyanide leaching of a gold due to the presence of slimes he would "as a matter of course have referred to the books by Adamson and Dorr and Bosqui".  The book written by Adamson is entitled "Gold Metallurgy in South Africa".  Mr. Robinson continues as follows:

"Besides referring to a text such as Dorr & Bosqui for guidance in such a situation I would have also consulted colleagues within the Mining industry who may have pertinent information available to them and also outside consultants.  In particular, I would in the normal course have referred such an investigation to the Australian Mineral Development Laboratories at Frewville in South Australia and/or to the Commonwealth Scientific and Industrial Research Organization."

Mr. Robinson contacted Mr. Woodcock at the CSIRO Division of Mineral Chemistry and sought advice on how to overcome a lack of permeability in the percolation leaching of gold and silver ores using cyanide solution because of the presence of excessive fines and clays.  Mr. Woodcock replied as follows:

"If faced with a need to look at such a problem I would consider my own experience and then conduct a literature search.  The literature search would include my own collection of data, standard texts, a computer search of Chemical Abstracts, and a manual search of related publications.  It would include reference to Australian and foreign patent literature, reference to other metals, and reference to other solvents.  I would also conduct appropriate experimental work.

I would also review the work of other research establishments and visit them if possible."

I note that the opponents' witnesses do not agree that the solution to the problem would require only the application of common general knowledge in using the technology used for metal ores other than those of gold or silver.  I should also point out that Mr. Robinson, who is employed by a company which is involved in processing gold containing ore, states he would not just have used his own knowledge to solve the problem but he would have sought the knowledge of parties outside his own company.
         In my view, an analysis of the documents lodged as exhibits to the declarations lodged on behalf of the opponents should indicate that mineral processing technology has been transferred from one metal ore to another using no more than common general knowledge, that is, without further problems solving in the sense of invention, if the opponents' assertions on obviousness are correct.
         These documents teach that heap leaching is an old metallurgical process first employed in Germany during the 16th Century and it is probable that more tons of mineral ore have been treated by heap leaching than by any other hydrometallurgical technique.  The majority of the materials treated have been oxidised copper but appreciable quantities of gold and silver ores along with uranium ores have also been heap leached.  The use of agglomeration in conjunction with percolation leaching of copper ores and concentrated tailings was investigated in detail in the 1930's by the U.S. Bureau of Mines and the papers describing these investigations were also published in Australia in the 1930's (e.g. exhibit REW‑7 was published in Australia in October 1930).
         I note that despite this early work, Mr. Wilmshurst in 1975 published a paper which described the results of pelletizing and percolation leaching of the copper ore from Burra (exhibit REW‑4).  The leaching of the pellets was abandoned because some pellets behaved satisfactorily but others did not, possibly due to the variability of the ore.
         Similarly Smith and Garrett published a paper in Australia in 1973 (exhibit JRK‑6) which comments that the technology of leaching uranium ore adopted in the 1940's and early 1950's was largely copied from the process and equipment in use for the cyanidation process for gold.  This paper describes a process for forming the ore into granules from which the uranium values are recovered by percolation leaching.  Again, in 1977 researchers at AMDEL described a similar process for pelletizing and percolation leaching of a uranium ore (exhibits REW‑5 and AEO‑3) which Mr. O'Meara (a declarant for the opponents) says:

"was guided by previous experience in the percolation leaching of green pellets to extract copper from its ore and on publications in relation to uranium and other ores."

It seems from my analysis that workers in the field of copper and uranium ores, for example, have to conduct extensive investigations in applying the known technology to the particular ore involved, despite the fact that knowledge of percolation and agglomeration techniques in respect of those metals is and was widespread.
         I conclude that in the present situation, whereas it would have been obvious to try agglomeration of the feed fines at the priority date, there is no evidence to indicate that the solution devised by Heinen et al would have been obvious.
         Proceeding to the general arguments on obviousness, Mr. Handley stated that the publications exhibited by the opponents' witnesses were evidence that the individual elements were part of common general knowledge but he argued that only the Dorr and Bosqui text book ("Cyanidation and  Concentration of Gold and Silver Ores") and the Pryor publication were actually part of common general knowledge.  In my view there is no proper evidence that any of the other publications exhibited formed part of common general knowledge.  With regard to Dorr and Bosqui's publication I conclude that only the synopses of the papers by Scrutton and Shephard and Skinner are part of common general knowledge.
Mr. Handley went on to submit that the process claimed was not obvious because there was a "long felt want" that the problem of extracting gold and/or silver values from fine ores should be solved (Blanco‑White (4th Edition) page 163). He also argued that the present process was in a similar position to the invention in the Olin case which the High Court found to be non‑obvious (Olin Corporation v. Super Cartridge Co. Pty. Ltd. 14 ALR 149 at page 171). Finally Mr. Handley pointed out that the question I had to consider was the obviousness of the combination and not whether each individual step was obvious. Dr. Emmerson on the other hand argued that all the features of the claimed process had to be determined by empirical optimisation and therefore he said that the specification did not teach a single solution to a universal problem for which a solution had been sought for a long time. Rather the specification merely claimed a desirable result. Therefore he submitted that the Olin case was not relevant to the present situation.
         The invention must be obvious to the hypothetical skilled addressee, or as the person is sometimes described, the person or persons who will be called on to solve the problem (Blanco‑White (Fifth Edition page 90).  However this skilled addressee is considered to be an unimaginative person with no inventive capacity.
          I have previously commented that the opponents' expert witnesses do not all agree that the solution to the problem of percolation leaching of gold and/or silver ore fines or slimes requires only the application of common general knowledge.
         It seems to me that the skilled addressee would know from the Pryor document and the synopsis of the Scrutton paper that clayey gold containing material can be formed into balls, with or without lime, before it is leached. Also from the synopsis of the Shephard and Skinner publication I consider that the skilled person would understand that there was a method of stabilizing agglomerated slimes by the formation of a cementing substance in the glomerules.  The conclusions based upon agglomeration tests are described in Dorr and Bosqui as follows:

"1.The porosity and permeability of finely ground ores can be greatly increased by moisture agglomeration.

2.Variations in the amount of solution used in agglomeration causes a noticeable difference in the amount of permeability.  The maximum permeability is reached between 10 and 18 per cent moisture.

3.A point of saturation occurs when too much solution is added, causing the glomerules to break down to a runny mud.  Beyond 22 per cent moisture, none of the materials tested had a measurable permeability by the method used.

4.The amount of solution necessary to give permeability by agglomeration increases with the fineness of the particles.

5.The permeability of loose beds of agglomerated material decreases with packing, but the permeability decrease becomes less as packing progresses."

My conclusions from the foregoing are that nothing much is really added by way of common knowledge to what could be gleaned from the arts of leaching metals other than gold or silver.
         In summary I would say it was obvious at the priority date of the claims to try agglomeration of the fines in order to obtain a successful leach. Binders such as lime were well known, as was cement.  As to aging it is and was common knowledge that lime and cement develop strength with time through chemical action involving water based liquids and that as binders they provide little strength without at least minimal aging.
         In this respect, Dr. Emmerson took the view that the broader claims, 9, 14, 15 and 19 were merely directed to the problem that required solution.  In the light of the art, I find that I agree with Dr. Emmerson and those claims are, in my opinion, obvious.
         Nevertheless, I reiterate the comment which I have made earlier under this heading, that is, that the solution envisaged by Heinen et al is not itself, obvious, in the light of the evidence presented.
Prior Use
         The opponents rely on a declaration by Mr. Harford indicating how he treated 200,000 tonnes of tailings at Grants Patch to recover gold from October 1976 to May 1979.  The applicants rely on the declaration of Dr. Keay who was also involved with the Grants Patch operation.
         Since Mr. Harford made no attempt to keep his operations secret, treated a fairly large tonnage of ore over about 2> years, and as Dr. Keay substantiates Mr. Harford's evidence I consider that the Grants Patch operation meets the criteria of public use. 
         Both witnesses are agreed on the tonnage of ore treated, its grade and the use of the elevating scraper and lime addition.  They are both agreed that no additional water over and above that which was contained in the tailings was added.
         The formation of some kind of balls is agreed by both witnesses, but Dr. Keay submits that these were not the porous agglomerates of the patent in suit, but were merely formed fortuitiously.  Mr. Harford maintains that he aged the agglomerates by discharging the feed/lime mixture from the scraper and air drying, whilst Dr. Keay asserts that the balls were discharged from the scraper merely for ease of loading into the leach vats.
         Moreover Dr. Henry, for the opponents, states that he doubts whether the balls of slimes formed at Grants Patch were truly porous agglomerates due to the overlong leach times (about 3 months) required.
          I think the experimental attempts by the opponents to prove that the Grants Patch operations did not produce porous agglomerates (Houtgraafs declaration) can be completely discounted due to the fact tht Grants Patch material was not used in the experiments.  Also the ore was treated by a different process to that which was used at Grants Patch.
          The evidence clearly establishes that at Grants Patch the following occurred:

(a)lime was added to gold containing fines having an inherent water content,

(b)lime was used at 0.3% by weight of feed,

(c)mechanical manipulation occurred in the elevating scraper and the lime/feed was not immediately discharged into a vat and leached,

(d)the mixture was formed into agglomerates at least sufficiently porous to allow percolation leaching, and which had enough strength to withstand complete flooding without further disintegration.

It appears to me that this evidence demonstrates that the degree of porosity and stability of the agglomerates formed at Grants Patch, falls within the scope of the present claims and that the agglomerate was "aged" for whatever reason.
         I thus consider that the process used at Grants Patch before the priority date of the application in suit is a prior use of the process defined in claims 1, 9, 14, 15 and 19.
Summary
         I have found serious defects in the application on grounds of non‑
compliance with section 40.  Some of the claims are obvious, and there has been prior publication by use and by document of many of the claims; further claims lack novelty accordingly.  It seems to me that the problems relating to obviousness and anticipation are largely consequential on the section 40 defects.  In my view it would be possible to amend the application in such a way as to patentably describe and define the solution to the problem as devised by Heinen et al, and I allow 60 days for the applicants to propose amendments accordingly.  I award all costs against the applicants.

(J.L. ROVETA)