Technological Resources Pty. Limited - [2021] APO 52

IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Technological Resources Pty. Limited [2021] APO 52

Patent Application: 2016347691

Title:Heap Leaching

Patent Applicant:                   Technological Resources Pty. Limited
Delegate:  R Subbarayan
Decision Date:  20 December 2021
Hearing Date:  Written submissions filed on 4 October 2021

Catchwords: PATENTS – examiner objections – whether claims lack support – whether claims lack inventive step – some claims lack support – some claims lack an inventive step – prior art cited earlier still highly relevant – application referred back to examination section for reassessment

Representation: Patent attorney for the applicant: Griffith Hack

IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Patent Application: 2016347691

Title:Heap Leaching

Patent Applicant: Technological Resources Pty. Limited
Date of Decision: 20 December 2021
DECISION
Claim 1 lacks support. Claim 15 is supported and hence the examiner’s objection to this claim should be withdrawn.
Claim 1 and its dependent claims 4-13 lack an inventive step in light of the common general knowledge and prior art D1.
Claim 15 does not lack an inventive step in light of the common general knowledge and prior art D1.
However prior art D4 cited in the International Search Report appears to be still highly relevant to claim 15 and possibly also to claim 1. I therefore refer the application back to the examination section for further assessment and if necessary, the issuance of another examination report.
In the circumstances, pursuant to sub-regulation 13.4(3), the final date to gain acceptance is set at four (4) months from the date of this decision.
REASONS FOR DECISION
BACKGROUND

Patent application 2016347691 in the name of Technological Resources Pty. Limited (the Applicant) was filed on 28 October 2016 as a PCT application (PCT/AU2016/051024) and claims an earlier priority date of 30 October 2015.
The Applicant requested expedited examination under the Global Patent Prosecution Highway program on 6 July 2020, based on the examination conducted by the United States Patent and Trademark Office (USPTO).
The examination request was accompanied by a statement of proposed amendments including a new set of claims that conform to the claims considered allowable by the USPTO.
A first examination report issued on 15 July 2020 finding that all of the claims lack an inventive step.
The Applicant responded on 29 July 2020 with detailed submissions as to why the claimed invention is inventive and that the examiner’s objection should therefore be withdrawn.
A second examination report issued on 20 August 2020, in which the examiner maintained the lack of inventive objection and also introduced new objections under section 40 that the application is not for one invention only and that each of the independent claims is not supported by matter disclosed in the specification.
The Applicant responded on 22 March 2021 disputing the examiner’s adverse findings in relation to inventive step and support but conceding the lack of unity findings and advising that they would address this once the other objections have been resolved.
A third examination report issued on 12 April 2021, in which the examiner maintained the lack of inventive step, lack of support and lack of unity objections.
On 15 July 2021, the Applicant filed a request to be heard in respect of the lack of support and lack of inventive step objections.
The Applicant was advised that the hearing would be through written submissions.
The Applicant filed their written submissions on 4 October 2021.
APPLICABLE LAW
The present application is governed by the Patents Act 1990 (“the Act”) as amended by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (“the Raising the Bar Act”). Thus, the standard of proof that applies in the present case is the balance of probabilities (subsection 49(1)). I must accept the application if satisfied on the balance of probabilities that the application complies with the Act. If I am not so satisfied, then I can refuse the application.
SPECIFICATION
The present invention relates to leaching of chalcopyrite ores for recovering copper from the ore.
The specification provides a brief overview of the leaching process.
“In conventional heap leaching of copper sulfide containing minerals (including chalcopyrite ores), mined ore is stacked into heaps, aerated through direct injection of air via aeration pipes extending into the heap and/or by natural convection through exposed areas of the heap, and irrigated with an acid solution for extraction of copper into solution. The copper is subsequently recovered from the acid solution by a range of recovery options including solvent extraction and electrowinning (SX/EW), cementation onto more active metals such as iron, hydrogen reduction, and direct electrowinning. The acid solution is regenerated and recycled through the heap to leach more copper from the ore in the heap. The ore in the heap may comprise agglomerates of fragments of ore. Leaching may be assisted by the use of microorganisms”.[1]
[1] Specification at page 1, lines 18-27
The specification then notes difficulties in leaching copper with existing processes.
“It is known that it is difficult to leach more than 20-40 wt.% of copper from chalcopyrite. The low copper recovery is often thought to be associated with the formation of a passive film on the surface of chalcopyrite”.[2]
[2] Specification at page 2, lines 14-16
The present invention seeks to achieve higher recoveries of copper from chalcopyrite in ore fragments.
This is achieved in the present invention by the addition of silver to the chalcopyrite agglomerate and then leaching the agglomerate.
“In general terms, the applicant has found that it is possible to achieve high levels (greater than 60 wt.%) of recovery of copper by leaching agglomerates of fragments of chalcopyrite ores (and ores containing other copper-containing minerals) that have silver dispersed in the agglomerates by adding silver to mined ore fragments prior to, or during, agglomeration of the ore fragments or adding silver to agglomerates of the ore fragments.
In particular, the applicant has found that low concentrations of silver, typically less than 2 g silver per kg copper in the chalcopyrite ores, dispersed on the surfaces of chalcopyrite in agglomerates makes it possible to achieve higher recoveries (greater than 60%) of copper from the ores in shorter leaching times compared to leaching agglomerates that do not have silver dispersed in the agglomerates. This is a significant finding, particularly in the context of leaching lower grade chalcopyrite ores, i.e. ores containing less than 1.25 wt.% copper, typically less than 1 wt.% copper.
The reason(s) for the effectiveness of silver dispersed on the surfaces of chalcopyrite in agglomerates of fragments of chalcopyrite ores, particularly in low concentrations, have not been fully established completely by the applicant”.[3]
“In broad terms, the invention relates to providing silver in a form and within a defined concentration range at a location of a copper-containing ore that successfully catalyses leaching of copper from the copper-containing ore, particularly chalcopyrite.
In the case of chalcopyrite ores, the invention relates to dispersing silver in a form and within a defined concentration range on the surface of chalcopyrite”.[4]
“The invention provides a method of leaching mined chalcopyrite ores that
includes the steps of:
(a) forming agglomerates of fragments of chalcopyrite ores and silver; and
[3] Specification at page 2, lines 27 – page 3, line 10
[4] Specification at page 3, lines 15-19
[5] Specification at page 3, line 30 – page 4, line 1
(b) leaching the agglomerates with suitable leach liquor”.[5]
The specification notes that chalcopyrite may already have a naturally occurring low silver concentration and hence the silver added according to this invention will be referred to as “added silver” in order to distinguish it from any naturally occurring silver concentrations.
The specification then provides a broad overview of the process with reference to figure 1 which is reproduced below.
This figure shows an agglomeration station 3 where feed materials chalcopyrite (7), silver (9), acid (11) and microorganisms (13) are agglomerated. The agglomerate is then collected in a heap (5) where the copper is leached from the agglomerates by the supply of a suitable leach liquor. The leached copper is recovered from the leach liquor in a copper recovery step. The regenerated leach liquor is then recycled to the heap to leach more copper from the chalcopyrite in the agglomerates in the heap.
The specification discloses that the agglomeration step can be carried out in a number of ways.
“Agglomeration step (a) may include forming agglomerates by mixing together
ore fragments and silver in an agglomeration step.
Agglomeration step (a) may include forming agglomerates by adding silver to
ore fragments and then mixing together ore fragments in an agglomeration step.
Agglomeration step (a) may include forming agglomerates of ore fragments in an agglomeration step and then adding silver to the agglomerates”.[6]
[6] Specification at page 4, lines 15-20
The specification also notes that the silver may be added to the agglomerate in a solid form or in a solution and that a preferred method of adding silver is in the form of an aerosol or as a mist.
“Agglomeration step (a) may include adding silver to the chalcopyrite ore fragments in the form of an aerosol, where the term ‘aerosol’ is understood to mean a colloidal suspension of particles, typically in powder form, in air or gas.
Agglomeration step (a) may include adding silver in solution to the chalcopyrite ore fragments in the form of a mist or a spray, where the terms ‘mist’ and ‘spray’ are understood to mean small droplets of silver solution suspended in air.
The selection of a mist/spray/aerosol as a medium for adding the silver solution to the chalcopyrite ore fragments makes it possible to maximise the delivery of a small
concentration of the silver to a substantially larger mass (and large surface area) of
[7] Specification at page 6, lines 7-17
chalcopyrite ore fragments. The mist/spray/aerosol approach makes it possible to deliver the silver to a substantial proportion of the chalcopyrite ore fragments”.[7]
The leaching step is carried out under controlled temperature conditions.
“Heap leaching step (b) may include controlling the heap temperature to be less than 75 °C, typically less than 65 °C, typically less than 60 °C, typically less than 55 °C, typically less than 50 °C, and more typically less than 45 °C”.[8]
[8] Specification at page 7, lines 27-29
The specification then describes various column tests that were conducted on chalcopyrite ore, of which one was without added silver and the others were with differing amount of low concentration added silver. The silver was in the form of silver nitrate dissolved in water and was added as a mist, sprayed onto the ore during agglomeration.
The test results are given in Table 3 that is reproduced below.[9]
Table 3- Column Test Summary for Varying Silver Dosage
Column tests conducted at P80 9 mm, 50 °C, pH 1.2.
Chalcopyrite Extractions were determined by Scanning Electron Microscope.
[9] Specification at page 19, lines 15-18
According to this table, the amount of copper extracted from chalcopyrite varied from 71.5% with no added silver to 92.6 with 1g added silver. The specification notes that it is therefore clear from this table that at “all silver dosages tested, there was a significant improvement in copper extraction compared to leaching without silver”.
The specification highlights other benefits such as lower costs and shorter leach periods
·“The use of low concentrations of silver minimises operating costs compared to processes that involve the use of higher concentrations of silver (and therefore higher costs given the cost of silver) and simplifies downstream processing steps.
·An opportunity for shorter leach periods to achieve a given copper recovery”.[10]
[10] Specification at page 11, lines 15-20
The specification as filed ends with 45 claims but as mentioned earlier the Applicant has proposed a new set of amended claims which the examiner considered were allowable. The amended claims are as follows.
1. A method of leaching chalcopyrite ores includes the steps of:
(a) forming agglomerates of fragments of chalcopyrite ores and silver, defined herein as “added silver”, the agglomeration step including adding silver in a solution as a spray or a mist or in a solid form as an aerosol to the chalcopyrite ore fragments while the fragments are being mixed together; and
(b) leaching the agglomerates with suitable leach liquor.
2. The method defined in claim 1 wherein the agglomerates formed in the agglomeration step (a) have a low added silver concentration of less than 2 g silver per kg copper in the ore in the agglomerates.
3. The method defined in claim 1 or claim 2 wherein the agglomeration step (a) includes adding silver to the chalcopyrite ore fragments in the aerosol.
4. The method defined in any one of the preceding claims wherein the agglomeration step (a) includes adding silver in the mist or the spray.
5. The method defined in any one of the preceding claims wherein the agglomeration step (a) includes forming agglomerates by also mixing together an acid with the chalcopyrite ore fragments and the added silver.
6. The method defined in claim 5 wherein the acid is sulphuric acid.
7. The method defined in any one of the preceding claims wherein the agglomeration step (a) includes forming agglomerates by also mixing microorganisms that can assist leaching of copper with the chalcopyrite ore fragments and added silver.
8. The method defined in any one of the preceding claims wherein the agglomeration step (a) includes simultaneously mixing and agglomerating fragments and the added silver.
9. The method defined in any one of the preceding claims wherein the leaching step (b) is a heap leaching step.
10. The method defined in claim 9 wherein the heap leaching step (b) includes controlling the heap temperature to be less than 75 ºC
11. The method defined in claim 10 wherein the heap leaching step (b) includes controlling the heap temperature to be less than 65 ºC.
12. The method defined in claim 10 wherein the heap leaching step (b) includes controlling the heap temperature to be less than 60 ºC.
13. The method defined in any one of claims 9 to 12 includes controlling the oxidation potential of the leach liquor during an active leaching phase of the step to be less than 700 mV versus the standard hydrogen electrode in the heap leaching step (b).
14. The method defined in any one of the preceding claims wherein the agglomerates formed in the agglomeration step (a) have an added silver concentration of less than 1 g silver per kg copper in the ore in the agglomerates.
15. A method of leaching chalcopyrite ores includes the steps of:
(a) forming agglomerates of fragments of chalcopyrite ores and silver, defined herein as “added silver”, wherein the agglomerates formed in the agglomeration step (a) have a low added silver concentration of less than 1 g silver per kg copper in the ore in the agglomerates; and
(b) heap leaching the agglomerates with suitable leach liquor, wherein the heap leaching step (b) includes controlling the heap temperature to be less than 75 ºC.
16. The method defined in claim 15 wherein the added silver concentration in the agglomerates is less than 0.5 g silver per kg copper in the ore in the agglomerates.
17. The method defined in claim 16 wherein the added silver concentration in the agglomerates is less than 0.25 g silver per kg copper in the ore in the agglomerates.
18. The method defined in claim 16 wherein the added silver concentration in the agglomerates is less than 0.125 g silver per kg copper in the ore in the agglomerates.
19. The method defined in claim 16 wherein the added silver concentration in the agglomerates is less than 0.075 g silver per kg copper in the ore in the agglomerates.
20. The method defined in any one of claims 15 to 19 wherein the heap leaching step (b) includes controlling the heap temperature to be less than 65 ºC.
21. The method defined in any one of claims 15 to 20 includes controlling the oxidation potential of the leach liquor during an active leaching phase of the step to be less than 700 mV versus the standard hydrogen electrode in the heap leaching step (b).
22. The method defined in any one of claims 15 to 21 wherein the heap leaching step (b) includes controlling the heap temperature to be less than 60 ºC.
23. The method defined in claim 22 wherein the heap leaching step (b) includes controlling the heap temperature to be less than 55 ºC.
CLAIM CONSTRUCTION
While no claim construction issues appear to be in contention, I will briefly discuss how I have construed certain features in the independent claims.
Claim 1
Claim 1 defines that the agglomeration step includes the limitation of “adding silver in a solution as a spray or a mist or in a solid form as an aerosol to the chalcopyrite ore fragments while the fragments are being mixed together”. This limitation will be met if any one of the defined alternatives is met. For instance, if a prior art discloses addition of silver by spraying, that is sufficient to disclose this feature.
I would also note that there is no requirement imposed by this definition that the silver is added on its own. The silver solution could also be added along with or even mixed with other liquids such as acids or other agglomeration medium that are also introduced during agglomeration. Even the present specification notes that the “acid may be added at the same time as, or prior to, or after the silver solution”[11] (my emphasis).
[11] Specification at page 6, lines 25-26
Claim 15
Claim 15 defines a step of “forming agglomerates of fragments of chalcopyrite ores and silver”. Unlike claim 1, this feature of claim 15 does not require that the silver is added to the chalcopyrite ore fragments while the fragments are being mixed together. As mentioned earlier, the specification notes with respect to this feature:
“Agglomeration step (a) may include forming agglomerates by mixing together ore fragments and silver in an agglomeration step.
Agglomeration step (a) may include forming agglomerates by adding silver to ore fragments and then mixing together ore fragments in an agglomeration step.
Agglomeration step (a) may include forming agglomerates of ore fragments in an agglomeration step and then adding silver to the agglomerates”.
Hence this step of claim 15 would be met even if the silver is added to the ore fragments before mixing together the ore fragments or after forming agglomerates of ore fragments.
SUPPORT
Subsection 40(3) requires that the claim(s) must be supported by matter disclosed in the specification. In Merck Sharp & Dohme Corporation v Wyeth LLC (No 3) [2020] FCA 1477 (Merck), Burley J explored the requirement of support at [546]- [547]:
“In CSR Building Products Ltd v United States Gypsum Company [2015] APO 72, Dr S D Barker adopted the summary provided by Aldous J in Schering Biotech at 252 – 253, which has been often followed in the United Kingdom (emphasis added):
...to decide whether the claims are supported by the description it is necessary to ascertain what is the invention which is specified in the claims and then compare that with the invention which has been described in the specification. Thereafter the court’s task is to decide whether the invention in the claims is supported by the description. I do not believe that the mere mention in the specification of features appearing in the claim will necessarily be a sufficient support. The word “support” means more than that and requires the description to be the base which can fairly entitle the patentee to a monopoly of the width claimed.
That approach encapsulates broadly the claim support obligation under s 40(3). To it may be added the requirement that the technical contribution to the art must be ascertained. Where it is a product, it is that which must be supported in the sense that the technical contribution to the art disclosed by the specification must justify the breadth of the monopoly claimed”.

In CSR Building Products Limited v United States Gypsum Company [2015] APO 72 (CSR) that was referred to with approval in Merck, the delegate Dr Barker formulated the following test in order to determine whether a claim is supported by the description.
- Construe the claims to determine the scope of the invention as claimed,
- Construe the description to determine the technical contribution to the art, and
- Decide whether the claims are supported by the technical contribution to the art.
The Technical Contribution to the Art
The examiner is of the view that the technical contribution to the art as disclosed in the specification comprises the addition of silver to the agglomerate in the form of a spray, mist or aerosol wherein the added silver has a silver concentration of less than 1 g silver per kg copper in the ore in the agglomerates and on this basis has formed the view that independent claims 1 and 15 lack support as claim 1 “omits any silver concentration feature” and claim 15 “omits any specific dispersion technique (spray/aerosol/mist)”.
The Applicant has however submitted that independent claims 1 and 15 both correspond to respective statements in the description that disclose principles of general applicability and are therefore supported.
In relation to claim 1 they point to page 14, lines 9-19 of the specification which states as follows.
“The applicant has found that adding silver as a solution in a fine mist or spray or as solid particles in an aerosol to fragments of chalcopyrite ores as the ore fragments are being mixed in a suitable mixer, such as a drum mixer, is a particularly suitable way of achieving a desirable dispersion of silver on the ore fragments.
The selection of a mist/spray/aerosol as a medium for adding silver to the chalcopyrite ore fragments makes it possible to maximise the delivery of a small concentration of the silver to a substantially larger mass (and large surface area) and to a substantial proportion of the chalcopyrite ore fragments.
The work carried out by the applicant indicates that adding silver as a fine mist or spray or aerosol facilitates interaction of silver with surfaces of chalcopyrite minerals within ore fragments.”
In relation to claim 15 they point to page 3, lines 1-7 of the specification which states as follows:
“In particular, the applicant has found that low concentrations of silver, typically less than 2 g silver per kg copper in the chalcopyrite ores, dispersed on the surfaces of chalcopyrite in agglomerates makes it possible to achieve higher recoveries (greater than 60%) of copper from the ores in shorter leaching times compared to leaching agglomerates that do not have silver dispersed in the agglomerates. This is a significant finding, particularly in the context of leaching lower grade chalcopyrite ores, i.e. ores containing less than 1.25 wt.% copper, typically less than 1 wt.% copper.”
In my view, support for the claims is not just about finding corresponding statements in the description which are alleged to be statements of principles of general applicability. The test given by the delegate in CSR, requires me to identify what is disclosed in the description as the technical contribution to the art and then determine whether the claims are supported by this technical contribution. Or as Justice Burley put it, does the technical contribution justify the breadth of the monopoly claimed.
As discussed earlier, the specification seeks to address the problem of difficulties in recovering higher percentage of copper from chalcopyrite using existing leaching processes.
“It is known that it is difficult to leach more than 20-40 wt.% of copper from chalcopyrite. The low copper recovery is often thought to be associated with the formation of a passive film on the surface of chalcopyrite”.[12]
[12] Specification at page 2, lines 14-16
The solution proposed by the present invention is to add low concentrations of silver to the chalcopyrite agglomerate before leaching.
“In general terms, the applicant has found that it is possible to achieve high levels (greater than 60 wt.%) of recovery of copper by leaching agglomerates of fragments of chalcopyrite ores (and ores containing other copper-containing minerals) that have silver dispersed in the agglomerates by adding silver to mined ore fragments prior to, or during, agglomeration of the ore fragments or adding silver to agglomerates of the ore fragments.
In particular, the applicant has found that low concentrations of silver, typically less than 2 g silver per kg copper in the chalcopyrite ores, dispersed on the surfaces of chalcopyrite in agglomerates makes it possible to achieve higher recoveries (greater than 60%) of copper from the ores in shorter leaching times compared to leaching agglomerates that do not have silver dispersed in the agglomerates. This is a significant finding, particularly in the context of leaching lower grade chalcopyrite ores, i.e. ores containing less than 1.25 wt.% copper, typically less than 1 wt.% copper.
The reason(s) for the effectiveness of silver dispersed on the surfaces of chalcopyrite in agglomerates of fragments of chalcopyrite ores, particularly in low concentrations, have not been fully established completely by the applicant”.[13]
[13] Specification at page 2, lines 27 – page 3, line 10
In my view, the second paragraph that I have quoted above represents the technical contribution to the art that is disclosed in the specification. While the first paragraph quoted above suggests that the invention would work with any concentration of added silver to the agglomerate, it is clear from reading the specification as a whole, that the low concentration of added silver where the added silver is expressed based on the weight of copper in the chalcopyrite is very much at the heart of the present invention. There is a clear emphasis in the description on the use of low concentrations of silver.
“Figure 2 shows that the addition of low concentrations of silver to the agglomerates of fragments of chalcopyrite ores had a significant impact on (a) copper extraction and (b) the leach times to achieve high copper extractions”.[14]
“It is clear that the low silver concentration in the C288 column had a significant impact on copper extraction”.[15]
“In summary, the column tests reported above show that the addition of silver to agglomerates of fragments of chalcopyrite ores, particularly low concentrations of silver, has a significant positive impact on copper recoveries from chalcopyrite minerals in the agglomerates and leach times”.[16]
[14] Specification at page 16, lines 23-25
[15] Specification at page 17, lines 1-2
[16] Specification at page 18, lines 7-10
All of the tests conducted were also with low concentrations of silver. Furthermore, as noted in the specification, the “use of low concentrations of silver minimises operating costs compared to processes that involve the use of higher concentrations of silver (and therefore higher costs given the cost of silver) and simplifies downstream processing steps”.[17]
[17] Specification at page 11, lines 15-18
Therefore, in my view, the technical contribution to the art disclosed in the description is the addition to the chalcopyrite ore of low concentrations of silver, typically less than 2 g silver per kg copper in the chalcopyrite ores, forming agglomerates of the chalcopyrite and added silver and then leaching the agglomerate.
Independent claim 15 clearly includes all of the features of the technical contribution to the art disclosed and is therefore supported.
Independent claim 1, on the other hand, does not include the limitation of the low concentration of silver. While there is nothing in the specification that would suggest that the claimed method would not work with any concentration of silver, the clear emphasis in the description, including all of the tests carried out, is on low concentrations of added silver based on the weight of copper in the ore. No embodiments that use higher concentrations of silver have been described or enabled. There is clearly a serious inconsistency between the invention defined in claim 1 and the description of the invention and its stated objects and benefits. In my view, the technical contribution to the art disclosed in the description does not justify a monopoly for any amount of added silver to the agglomerate.
In relation to the Applicant’s reference to page 14, lines 9-19 of the specification as providing support for claim 1, I note that even here there is a clear reference in lines 14-15 to “the delivery of a small concentration of the silver” (emphasis added).
Therefore, I find that claim 1 is not supported by matter disclosed in the specification.
INVENTIVE STEP
The statutory basis for inventive step is set out at s7(2) and s7(3) of the Act, and is reproduced below:
(2) For the purposes of this Act, an invention is to be taken to involve an inventive step when compared with the prior art base unless the invention would have been obvious to a person skilled in the relevant art in the light of the common general knowledge as it existed (whether in or out of the patent area) before the priority date of the relevant claim, whether that knowledge is considered separately or together with the information mentioned in subsection (3).
(3) The information for the purposes of subsection (2) is:
(a) any single piece of prior art information; or
(b) a combination of any 2 or more pieces of prior art information that the skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have combined.
The test for obviousness is whether it would have been a matter of routine to proceed to the claimed invention.
“The test is whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be the steps of the inventor or not.” (Aicken J in Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd [1981] HCA 12 at [45]; 148 CLR 262 at 286)
The High Court in Aktiebolaget Hässle v Alphapharm Pty Ltd [2002] HCA 59 (Alphapharm) at [51] - [53] also approved the approach taken in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd [1970] RPC 157 at 187 in which Graham J had posed the reformulated Cripps question:
“Would the notional research group at the relevant date in all the circumstances directly be led as a matter of course to try [the claimed invention] in the expectation that it might well produce a useful [desired result]?”
In relation to what level of inventiveness is required to sustain a patent, the Full Federal Court in Garford Pty Ltd v Dywidag Systems International Pty Ltd [2015] FCAFC 6 stated as follows at [44]:
“The inventiveness required to sustain a patent for a claimed invention is quite small. A “scintilla” of inventiveness is all that is required: Alphapharm at [195]. However, there must still be “some difficulty overcome, some barrier crossed” (per Lockhart J in RD Werner & Co Inc v Bailey Aluminium Products Pty Ltd [1989] FCA 57; (1989) 25 FCR 565 at 574) or some contribution to the art “beyond the skill of the calling” (Allsop Inc v Bintang Ltd [1989] FCA 297; (1989) 15 IPR 686 at 701)”.
(D1) AU 749366 and CGK
The examiner’s inventive step objection is based on prior art D1 and the common general knowledge in the art.
D1 is titled “Silver Catalysed Leaching Of Chalcopyrite Ore”. It notes the difficulties in heap leaching copper from chalcopyrite.
“To date, however, it has not been possible to subject chalcopyrite to a heap leaching process since chalcopyrite has been highly resistant to leaching for the reasons set out above”.[18]
[18] D1 at page 5, lines 9-12
The object of D1 is therefore to “provide a process for bioleaching of chalcopyrite whereby copper may be extracted at satisfactory yields”.[19]
[19] D1 at page 5, line 31 – page 6, line 2
It is therefore clear that D1 is directed to addressing the same problem as the claimed invention.
The solution proposed by D1 is the addition of silver to the chalcopyrite prior to leaching.
“Surprisingly, it has now been discovered that rapid bioleaching of chalcopyrite can now occur whereby leaching of chalcopyrite can occur if the chalcopyrite ore is treated with silver prior to leaching”.[20]
[20] D1 at page 6, lines 3-6
D1 also discloses that the silver can be added during the agglomeration step and the quantity of silver added is 10-500 mg/kg of ore.
“In a first embodiment of the invention, the bioleaching process includes an agglomeration step wherein the chalcopyrite ore is mixed with water and/or sulphuric acid or other agglomeration medium in the presence of silver where the concentration of silver suitably in the form of Ag+ included in the agglomeration medium is from 10-500 mg/kg of ore and more preferably from 20-200 mg Ag/kg of ore. It is preferred that the concentration of silver does not exceed 500 mg/kg of ore because concentrations in excess of this amount (i) is uneconomic and also may not be satisfactory in use; and (ii) may adversely effect the bacteria utilized in the subsequent bioleaching of the ore”.[21]
“However, in accordance with the first embodiment of the invention, the crushed ore is agglomerated in the presence of silver which preferably is in the form of Ag+ which may deposit on the agglomerated particles of the ore as a solid layer so that the solid silver is comprehensively and uniformly distributed throughout the agglomerated particles”.[22]
“The most convenient way to add the silver is as a solution during agglomeration. If the process does not use agglomeration, the silver can be sprinkled on the ore as it is packed”.[23]
[21] D1 at page 6, lines 14-23
[22] D1 at page 8, lines 8-13
[23] D1 at page 17, lines 17-19
D1 also notes that the added silver can be included in the agglomeration medium.[24]
[24] D1 at claim 2
The trials that are described in D1 were carried out with chalcopyrite ore containing 0.98 wt
% Cu and the amount of added silver was 200 mg Ag/kg of ore.
The examiner’s objection to claim 1 in the third report reads as follows:
“Claim 1 lacks an inventive step when compared with prior art D1 when combined with common general knowledge in the art.
D1 discloses the features presented in the previous report. D1 also directly teaches (page 17, lines 17-18): “The most convenient way to add the silver is as a solution during agglomeration”.
As per claim 1, D1 does not teach spraying as the mode of silver delivery during agglomeration – however the examiner is directly presenting the attorney with three examples where a solution is sprayed in a manner that disperses and delivers said solution to a large surface area of target material. The scenarios were presented in the previous report and are reiterated here: D1, page 26, line 29-31; D2 page 6, line 31-33 and page 7 lines 34-35; D3 page 9, line 20-22. The examiner is referring to these scenarios as examples of common general knowledge – specifically knowledge that misting/spraying/aerosol dispersion of a solution will enable large surface area distribution to some target material. The examiner is not relying on the context of what solution is being sprayed, nor the target material onto which spray is delivered – rather, plainly, these are examples of spray delivery being well known to disperse a solution to a large surface area of material.
Therefore while D1 does not teach spraying as the means of delivering silver as a solution during agglomeration – this mode of delivery is considered obvious, and is not a difference considered to extend the art in terms of patentable inventive step”.
It is evident from the disclosure of D1, that there is a clear teaching in D1 for the addition of only low concentrations of silver, either in solid form or in solution, in such a manner that it is uniformly distributed on the surface of the agglomerate particles or fragments.
D1 does not however explicitly disclose the manner in which the silver, in solid form or in solution form, is added to the agglomerate.
So, the question is whether the person skilled in the art armed with the common general knowledge and the disclosure of D1, would have as a matter of routine, supplemented the teaching in D1 of adding silver to the agglomerate, by choosing spraying or misting as the mode of delivering the silver to the agglomerate.
The examiner has asserted that spraying liquids into ore during agglomeration is common general knowledge in the art and has supported this assertion by citing documents D2 and D3 both of which disclose spraying liquids into an ore during agglomeration. The examiner has also relied on D1 itself where it is clearly stated that in embodiments where the ore is not agglomerated, the silver may be added to the ore by “sparging the silver solution over the top of the ore by use of sprinklers, jets or wobblers”[25]. The examiner is of the view that, armed with this common general knowledge, the person skilled in the art would have as a matter of routine chosen to deliver the silver solution to the agglomerate of D1 by spraying and that the invention of claim 1 therefore lacks an inventive step.
[25] D1 at page 6, lines 30-31
The Applicant has however refuted this and has submitted as follows.
“5. Context is very important. Relevant context in the present instance is the material being distributed, namely silver.
(a) There is a significant difference between the considerations for delivering high volume additions such as (a) a leach solution onto a heap of pellets (D2) or (b) a flocculant during agglomeration (D2) or (c) an inoculum during agglomeration (D3) on the one hand and delivering a high cost addition, i.e. silver (claim 1), on the other hand.
6. The citations do not mention aerosol delivery, i.e. delivery of silver in a solid form in an aerosol.
7. Further to item 6, forming silver into an aerosol would significantly increase pump pressure and therefore process overheads. There is no incentive to increase overheads by increasing pump pressure as the prior art does not teach that forming silver into an aerosol would produce an improved yield of copper.
8. Target material is also very important.
(a) Claim 1 is very specific to chalcopyrite ores.
(b) These are quite different ores to nickel-containing ores of D2.
9. The antimicrobial properties of silver teach away from the addition of silver during agglomeration.
(a) It was suspected by the applicant that adding silver during agglomeration would kill microorganisms that can assist leaching of copper that are often added during agglomeration (because silver is an antibacterial agent)”.
I do not find the Applicant’s submissions persuasive.
In relation to items 6 and 7, as noted earlier, there is no requirement that D1 should disclose aerosol as long the alternative of spraying or misting is disclosed or would have been a matter of routine.
Item 9 is moot as D1 clearly teaches adding silver during agglomeration.
In relation to the other items, while I accept that due consideration must be given to the material that is being added, namely silver, and the material to which it is added, namely chalcopyrite, I can see nothing in the objection that would suggest that this has not been done by the examiner.
As I noted earlier, there is no explicit disclosure in D1 of how the silver is added to the agglomerate in the first embodiment. That does not mean that the person skilled in the art would ignore the teachings of this document that is clearly addressing the same problem as the claimed invention. Patent specifications often do not provide every technical detail of the invention and it is left to the person skilled in the art to add finer or missing details using the common general knowledge in the art.
I do not think that there is any doubt that spraying or misting a solution into an ore during agglomeration of the ore was common general knowledge in the art. As noted by the examiner, documents D2 and D3 cited by him are nothing more than examples of prior art that use spraying as a means of adding a liquid to on ore. The Applicant also does not appear to dispute this but only highlights the fact that neither of these are for adding silver to chalcopyrite. However, I do not see the need for the examiner to identify documents that are specifically for adding silver to chalcopyrite. The question is would the person skilled in the art, armed with the common general knowledge of adding liquids to ores during agglomeration by spraying, have as a matter of routine employed spraying as a means of adding the silver to chalcopyrite ores during agglomeration.

The answer in my view is yes. There are only limited number of ways one could add the silver solution to the chalcopyrite ore fragments while the fragments are being mixed. It is also clear that given the low concentration and volume of silver solution there is a need to employ a technique that will enable the solution to be distributed to as much of the surface of the fragments of the ore as possible. Spraying or misting is very much one such technique. As noted earlier, even within D1 there is a teaching to use spraying of the silver solution for the second embodiment where there is no agglomeration. Adoption of the same technique for the first embodiment as well would be nothing more than a logical step. Furthermore, as discussed earlier, claim 1 includes within its scope the alternative in which the silver is mixed with the agglomeration medium and then added to the ore. D1 clearly discloses that the silver may be included in the agglomeration medium and as highlighted by the examiner spraying of the agglomeration medium is known in the art. In my view, the person skilled in the art would have as a matter of course employed spraying as a means of delivering the silver solution with a reasonable expectation of success and by doing so would have arrived at the claimed invention. Claim 1 therefore lacks an inventive step in light of the common general knowledge and the disclosure of D1.
Claim 15
The examiner’s objection to claim 15 in the third report reads as follows:
“D1 discloses a lower bound of silver addition as 1.02g silver per kg of copper in the ore agglomerates – see the IPRPII conversion of concentrations in D1 Table 1. Therefore, D1 does not disclose: added silver concentrations of less than 1g silver per kg of copper in the ore in the agglomerates.
The examiner reasserts that it is obvious to apply the method of D1 to chalcopyrite ores with higher copper concentrations; (particularly for the benefit of reduced silver usage) and in doing so would arrive at a lower effective concentration of silver in the ore. As such claim 15 remains obvious over the teachings of D1, said claim does not extend the art in terms of patentable inventive step”.
Claim 15, unlike claim 1, does not specify that the silver is added by spraying or as an aerosol, and hence that issue does not arise in relation to the disclosure of D1. However, the quantity of silver that is to be added is a specified limitation in claim 15. While D1 also specifies the quantity of silver that is to be added, this quantity is expressed in different terms to that defined in claim 15 and hence a direct comparison becomes difficult. The examiner has therefore had to resort to performing some calculations to the quantities specified in D1 and based on that formed the view that claim 15 also lacks an inventive step.
Claim 15 requires that the added silver has a low concentration of less than 1 g silver per kg copper in the ore.
D1 teaches that the concentration of silver is from 10-500 mg/kg of ore and more preferably from 20-200 mg Ag/kg of ore and also it is preferred that the concentration of silver does not exceed 500 mg/kg of ore because concentrations in excess of this amount (i) is uneconomic and also may not be satisfactory in use.
While claim 15 specifies the added silver in terms of g/kg of copper in the chalcopyrite ore, D1 specifies the added silver in terms of g/kg of chalcopyrite ore. Clearly a direct comparison is not possible.
In D1, the chalcopyrite ore that was used in the tests had a Cu concentration of 0.98 wt% and the silver concentration was 200 mg Ag/kg of ore. In terms of silver concentration per kg of Cu, this works out to 20.4 g/kg of Cu. However, as noted by the examiner, D1 does contemplate adding only 10mg/kg of ore and if this concentration of silver were to be added to the test ore, this would give a silver concentration of 1.02 g/kg of Cu. This is the lowest concentration of silver /kg of Cu in the ore that is taught by D1. Clearly there is no teaching of adding less than 1g/kg of Cu as defined in claim 15.
The examiner has taken the view that, if the chalcopyrite ore that is used were to be more copper rich than the ore that is used in the tests of D1, then the silver concentration would be below 1g/kg of Cu as required by claim 15.
The Applicant has refuted this reasoning and has submitted as follows:
“Basing the addition of silver on the amount of ore is a different approach to silver addition to that of the applicant. The invention bases silver addition of the amount of copper in ore.
It is evident from the above extract from the Examination Report that the Examiner had to make a “conversion of concentrations” in order to compare the low silver concentration of the claimed invention and D1.
We submit that the need for a conversion means that there is no comparison between the claimed invention and D1 that is evident directly from the disclosure in D1 considered as a stand-alone document.
We submit that the different approaches to silver concentration in the invention and D1 indicate different teachings and distinguish the claimed invention from D1.
These are not differences that are based on units of measurement, where conversion of units is appropriate to make a proper comparison of a claim and a prior art document that are teaching the same approach to an additive.
This is a difference of substance, and the conversion is the result of hindsight analysis.
Moreover, the examples in D1 teach a silver addition based on a specific copper
concentration, i.e. copper grade (0.98% grade of copper).
D1 does not teach the use of a constant amount of silver with different copper grades.
Therefore, it is an extension of the disclosure in D1 to extrapolate the stated amount of silver added for examples on a specific copper grade to higher copper grades. We submit that this extension is not obvious and reads more into D1 than is reasonable”.
I am inclined to agree with the Applicant. Even though it was well known that the percentage of copper in chalcopyrite can vary and despite the fact that the experiments in D1 were carried out on a test sample of chalcopyrite ore having 0.98 wt % Cu, D1 still teaches as a broad principle that the concentration of added silver is to be based on the weight of the ore. There is no suggestion in D1 that the concentrations of added silver should be varied from the specified concentrations depending on the weight of copper in the chalcopyrite ore that is used. The claimed invention on the other hand takes the approach that the estimated weight of copper in the chalcopyrite ore is a critical parameter for estimating the amount of silver to be added. Whilst I can understand the examiner’s reasoning that if a chalcopyrite ore that is more copper rich than the test ore of D1 were to be used with the silver concentration taught in D1, the concentration of added silver will be below 1g/kg of Cu, that is not sufficient to establish that the claimed invention is obvious. There is no teaching in D1 that would have directly led a person skilled in the art to base the concentration of added silver on the estimated weight of copper in the ore and furthermore I have no evidence that they would have done that.
I am not satisfied that the invention of claim 15 is obvious in light of the common general knowledge and the disclosure of D1.
Dependent claims
Claims 2 and 14 define the added silver has a concentration of less than 2g and 1g per kg copper respectively. I have found that there is no teaching in D1 to base the quantity of added silver on the weight of copper in the ore.
While it could be argued, as the examiner did, that if, as per the broad teaching of D1, a concentration of added silver of 10 mg Ag/kg of chalcopyrite ore was used with the test sample of chalcopyrite ore (with 0.98 wt % Cu), then the added silver would have a concentration of 1.02 g per kg copper, as submitted by the Applicant, the actual concentration of added silver used in the practical experiment of D1 was 200 mg Ag/kg of ore and this converts to an added silver concentration of 20.4 g per kg of copper. There is no practical experiment in D1 to suggest or support that the copper in the chalcopyrite ore can be viably leached with an amount of added silver at this lower end of the specified range. I am not satisfied that claim 2 or claim 14 lacks an inventive step over D1.
Claim 3 defines that the silver is added in a solid form as an aerosol. The examiner has not provided any documents that show silver or other agglomeration medium being added as an aerosol. I am therefore not satisfied that claim 3 lacks an inventive step.
Claim 4 defines that the silver is added in a mist or spray. It follows that claim 4 lacks an inventive step.
Claims 5 and 6 defines addition of sulphuric acid with the chalcopyrite ore fragments and the added silver. The addition of sulphuric acid is disclosed in D1. These claims therefore lack an inventive step.
Claim 7 defines the mixing of microorganisms with the agglomerate. D1 discloses the addition of bacterial inoculate. This claim therefore lacks an inventive step.
Claim 8 defines simultaneously mixing and agglomerating fragments and the added silver. This is disclosed in D1. This claim therefore lacks an inventive step.
Claim 9 defines a heap leaching step. This is disclosed in D1. This claim therefore lacks an inventive step.
Claims 10-12 define controlling the heap temperature to be less than 75ºC, 65ºC and 60ºC. D1 discloses a heap temperature of 32ºC. These claims therefore lack an inventive step.
Claim 13 defines “controlling the oxidation potential of the leach liquor during an active leaching phase of the step to be less than 700 mV”. Although this is not disclosed in D1, the examiner is of the view that this feature is common general knowledge in the art or a mere design choice and hence this claim lacks an inventive step. The Applicant has not made any submissions to the contrary and there is nothing in the specification to suggest that there is there is any ingenuity involved in arriving at this value. I am therefore satisfied that this claim lacks an inventive step.
Claims 16-23 are dependent on claim 15. It follows that these claims also do not lack an inventive step.
OTHER OBSERVATIONS
While reviewing the prosecution history of this application, including the international search and examination phase, I came across prior art document WO2000/037690 that had been cited as a novelty destroying document, but the objection was then subsequently dropped during preliminary examination based on submissions from the Applicant. I have however formed the view that this document is still highly relevant to the present claims for the reasons explained below.
WO2000/037690 (University of British Columbia) (D4)
D4 is titled “Silver-Catalyzed Bio-Leaching Process For Copper Extraction From Chalcopyrite Heap”. Some of the relevant passages from this document are as follows (emphasis added):
“The present invention provides a process for using an economically low concentration of silver catalyst to extract a commercially meaningful proportion of copper from recalcitrant chalcopyrite ores”.
In one aspect, the present invention provides a method of leaching copper from a chalcopyrite ore comprising adding to the ore a catalytic amount of soluble silver. The catalytic amount being from about 0.25 to about 1.5 g Ag/kg Cu. In alternative embodiments, the catalytic amount may be from about 0.5 to about 1.5 g Ag/kg Cu, or from about 0.75 to about 1.5 g Ag/kg Cu, or about 1 g Ag/kg Cu”.[26]
[26] D4 at page 5, lines 6-13
“The temperature of the ore body may be adjusted to a selected temperature to improve leaching, such as a temperature of between about 20 and 40°C”.[27]
“In accordance with the invention, the addition of a catalytic amount of soluble silver to the ore may be carried out in a wide variety of ways. A soluble silver salt, such as silver sulfate, may be added in solid form to the ore body. Such solid silver salts may be physically mixed with a portion of the ore body. Alternatively, the silver may be dissolved before it is added to the ore, in which case the solution in which the silver is dissolved may be adapted to optimize delivery of a catalytic amount of silver to the ore”.[28]
“All or a portion of the ore may be treated in a chemical activation stage in which the ore is contacted with the soluble silver for a period of time. This contacting step may for example be carried out with agitation in order to facilitate contacting of the ore particles with the silver catalyst”.[29]
“In many of the examples, the ores were first treated in a chemical activation stage in which the ore is contacted with a solution of silver sulfate (AgSO4) for about 1 hour with agitation. Following chemical activation, the ore may be separated from the silver solution and dried to form an agglomerated ore”.[30]
“Leaching may be conducted on a continuous basis for a leaching period to extract at least about 40% of the copper from the ore”.[31]
“Examples 17, 18 and 19 demonstrate the effect of varying silver catalyst concentrations, showing that yields in excess of 40% may be obtained using silver concentrations of 0.25, 0.5 and 1.0 g Ag/kg Cu, where extractions are carried out at pH 1.8 (1/10 OK medium) and at 35°C. These results also show that copper yields may be optimized in some embodiments by using silver concentrations up to 1.0 g Ag/kg Cu”.[32]
[27] D4 at page 5, lines 30-31
[28] D4 at page 8, lines 21-26
[29] D4 at page 8, line 29 – page 30, line 2
[30] D4 at page 14, lines 11-14
[31] D4 at page 10, lines 23-24
[32] D4 at page 17, lines 7-11
It is clear from these passages that D4 is directed to addressing the same problem as the claimed invention and also teaches the claimed solution of adding silver to the ore in the concentration of less than 1g Ag/kg of Cu. It is worth noting that D4, like the present invention, teaches that the added silver should be based on the weight of copper in the ore and not based on the weight of the ore.
The reason the objection based on this document appears to have been dropped by the examiner was because of the Applicant’s submission that this document does not disclose forming agglomerates of chalcopyrite ores and added silver prior to leaching of the ore. However, it is evident from the passages reproduced above, that D4 does disclose adding silver to the ore with agitation and then agglomerating the ore prior to leaching the ore.

100. I would also add that given that both D1 and D4 are directed to addressing the same problem as the claimed invention, there may even be strong motivation to combine the disclosures of these documents and such a combination may also make a number of claims obvious.
101. It is therefore appropriate in the circumstances that I refer the application back to the examination section for the examiner to re-evaluate the disclosure of D4 and if necessary, raise further novelty and/or inventive step objections based on D4.
CONCLUSION
102. Claim 1 lacks support. Claim 15 is supported and hence the examiner’s objection to this claim should be withdrawn.
103. Claim 1 and its dependent claims 4-13 lack an inventive step in light of the common general knowledge and prior art D1.
104. Claim 15 does not lack an inventive step in light of the common general knowledge and prior art D1.
105. However prior art D4 cited in the International Search Report appears to be still highly relevant to claim 15 and possibly also to claim 1 with respect to novelty and/or inventive step. I therefore refer the application back to the examination section for further assessment and if necessary, the issuance of another examination report.
106. In the circumstances, pursuant to sub-regulation 13.4(3), the final date to gain acceptance is set at four (4) months from the date of this decision.
R Subbarayan
Delegate of the Commissioner of Patents