Robert B. Clay v ICI Australia Operations Pty Ltd

[1984] APO 24

In the Matter of the Patents Act 1952

‑ and ‑

In the Matter of Application No.521821 for a Patent by ROBERT B. CLAY

‑ and ‑

In the Matter of Section 59 Opposition thereto by ICI AUSTRALIA OPERATIONS PTY LTD

DECISION OF A SUPERVISING EXAMINER OF PATENTS:

Patent Application 521821 entitled "Water Resistant Blasting Agent and Method of Use" is based on a US application with a priority date of 25 August, 1978 and acceptance of the application was notified in the Official Journal dated 29 April, 1982.

On 28 July, 1982 ICI Australia Operations Pty Ltd (ICI) lodged notice of opposition under section 59.  After service of the evidence was completed on 18 May 1984, the matter was heard in Melbourne on 23 August, 1984.  Dr. R.C. Hinton of ICI Australia represented the opponent and Mr. J.A. Waters, patent attorney of Phillips, Ormonde and Fitzpatrick represented the applicant who personally attended.  Although the notice of opposition specified grounds (c) to (e) and (g) to (i) of sub‑section 59(1) the only grounds argued at the hearing were that the invention, so far as claimed, in any claim, was obvious and had been anticipated and that the complete specification does not comply with the requirements of section  40.

The Specification

The specification in the form accepted states that the invention relates to an ammonium nitrate explosive composition which avoids the deficiences of previous compositions.  The improved composition, which is highly water resistant, sinks in water and has good bulk energy or blasting power but can be detonated reliably without being hazardous to handle.  Then follows a description of the invention in identical terms to those of claim 1.

‑2‑

The specification describes the composition of the invention as a well mixed stable combination of two components.  The first component is an essentially solid, dry granular or prilled oxidizer salt or mixture of salts which may include up to 10% liquid hydrocarbon fuel.  The second component is an oily or greasy emulsion of an aqueous solution of powerful oxidiser salts and an oily fuel stably emulsified with a small but effective quantity of a water‑in‑oil emulsifier.  The emulsion has to be fluid enough to fill the cavities and interstices in the solid component.  In this way the overall density of the composition is made greater than the density of water.  For practical use however, the density of the composition must not be too great, therefore a density controlling sensitizer, in the form of tiny hollow microspheres or microballoons is included in the emulsion.

The specification goes on to discuss British patent No. 1,306,456 which Mr. Waters admitted was an error for No. 1,306,546.  This discussion reads as follows ‑

"Prior art has suggested also the combining of greaselike materials with ammonium nitrate prills, or with prills and oil mixtures, as in British patent No. 1,306,456, for example.  In this reference, a solution of ammonium and other nitrates in water was emulsified with oil and fertilizer grade ammonium nitrate, with or without oil added thereto, were mixed into the emulsion.  The compositions, however, required the addition of hydrogen peroxide and/or other sensitizers, plus use of large proportions of emulsifier.  In addition, they cannot be used in deep boreholes without adding density reducing agents, because a tall column of explosive in a borehole is compressed so much in its lower parts that it cannot be detonated".

Sorbitan monooleate, sorbitan monostearate and sorbitan monopalmitate are the preferred emulsifiers used in the present blasting agents in the preferred range of 0.02 to 0.3% by weight of the total composition.

Then follows a description of the preferred embodiment in which the blasting agent is compared with a conventional ammonium nitrate/fuel oil explosive.  The detonability of blasting agents of varying composition, density and diameter is described.  There are also short discussions concerning the choice of emulsifier, the effect of the use of different quantities of emulsifier, the effect of using heavier oil, the effect of energetic mixing of the composition and the effect of using different salt combinations.

A method of using the blasting agent in boreholes partly filled with water is then described.

‑3‑

The claims read as follows:

"1.A blasting agent consisting of a combination of:

(a)40 to 60 percent by weight, based on the total composition, of a water‑in‑oil emulsion comprising powerful oxidizer salt in aqueous solution, said solution being dispersed in an outer continuous oil phase and including a gas‑trapping density‑reducing material to sensitize the composition and improve its detonability,

(b)60 to 40 percent by weight of a substantially solid particulate oxidizer consisting primarily of ammonium nitrate,

(c)the emulsion being blended into and through the solid particulate oxidizer so as to fill substantially completely the voids and interstices in and between the solid particles so as to substantially exclude water.

2.Composition according to Claim 1 in which the oxidisers in the emulsion are selected from the group which consists of the ammonium, alkali metal and alkaline earth metal nitrates, chlorates and perchlorates.

3.Composition according to Claim 1 in which the emulsion constituent per se is substantially oxygen balanced with a fuel oil and in which the particulate oxidizer material consists of ammonium nitrate substantially oxygen balanced with fuel oil.

4.Composition according to Claim 1 in which the solid particulate material is ammonium nitrate and the emulsion component contains sufficient oil to oxygen balance the ammonium nitrate.

5.Composition according to Claim 1 in which the emulsion component includes calcium nitrate and ammonium nitrate.

6.Composition according to Claim 5 in which the emulsion component includes sodium nitrate.

7.Composition according to Claim 1 in which the emulsion component includes an aqueous solution of ammonium nitrate and calcium nitrate and also includes a water soluble liquid fuel selected from the group which consists of the water soluble alcohols, glycols and formamide.

8.A composition according to Claim 1 in which the oil includes an oleaginous material which is substantially solid at normal temperatures.

9.A composition according to Claim 1 in which the water‑in‑oil emulsion contains about 0.02 percent, based on the weight of the total composition, of emulsifier which is substantially as effective in emulsifying as sorbitan oleate.

10.Composition according to Claim 1 which includes liquid oil in both the emulsion and the solid particulate component.

‑4‑

11.Composition according to Claim 1 in which the water‑in‑oil emulsion contains from 0.02 to 0.3 percent, based on weight of the total composition, of an emulsifier selected from the group which consists of sorbitan oleate, sorbitan stearate, sorbitan palmitate, and sorbitan laurate.

12.Composition according to Claim 1 in which the substantially solid particulate oxidizer includes up to 10 percent of liquid hydrocarbon fuel liquid and otherwise comprises ammonium nitrate, sodium nitrate and calcium nitrate.

13.Composition according to Claim 1 having an overall oxygen balance between minus 12 and plus 4 percent.

14.Composition according to Claim 1 in which the oxidizer salt consists of ammonium nitrate and at least one other salt to enhance water solubility.

15.A method of blasting in situations in which the borehole or other blasting site contains water in the lower part thereof, which consists in filling the site, at least up to the water level, with a composition according to any one of the preceding claims, and filling the upper portion of the blasting site, above the water level, with a substantially dry solid nitrate explosive sensitized with a fuel, the composition having greater blasting power at the bottom than at the top."

I note that an emulsifier is not an essential part of component (a) in claim 1.  However I consider that in the light of the description, the skilled addressee would understand that an emulsifier would be required in the emulsion component (a) if a stable emulsion could not be formed in the abscence of the emulsifier.  I also note that an essential part of the emulsion component is a "gas‑trapping density‑reducing material" to sensitize the composition whereas on page 4, line 16 a "density controlling sensitizer" is described as a preferred feature of the composition.

A more serious problem with Claim 1, in my view, is the definition of component (b) as "a substantially solid particulate oxidizer".  From the description it is clear that this component may include up to 10% of a liquid hydrocarbon fuel, which of itself is not an oxidizer, although the overall combination of the salt and the hydrocarbon fuel may be an oxidizer.  However in claim 3 and a corresponding passage in the description component (b) can be  ammonium nitrate which is "substantially oxygen balanced" with fuel oil.  I interpret this to mean  that component (b) contains sufficient oxygen atoms to completely oxidize substantially all the nitrogen, hydrogen and carbon atoms without leaving an excess of oxygen atoms.  Therefore such a component does not lie within the scope of the term "oxidizer" and it follows that the definition of component (b) in claim 1 is unclear.

‑5‑

The Evidence

The opponent's evidence in support of its opposition consists of a statutory declaration made by Dr Vladimir Sujansky with one annexure and a statutory declaration made by Dr Timothy Nicholls Hagan with one annexure.

Dr Sujansky declares that he is a chemist employed in the Development Section of the ICI explosives factory in Australia and that during the period 1978 to l981 he was seconded to ICI in the United Kingdom to form part of a special team continuing fundamental research in new explosives.  He states that since 1971 a routine part of his duties has been to monitor developments in the area of emulsion explosives by reading relevant patent specifications and abstracts when they are published in Australia.  Dr Sujansky declares that the area of water‑in‑oil explosives was well known to him at the priority date of the present specification and was common general knowledge to the technical personnel of the Explosive Division of ICI Australia.  He states that he was aware of the significance of US patents nos. 3,447,978 and 3,161,551 and declares that he used the explosives described in the South African patent application, which forms the annexure to his declaration in his work on explosives.  The annexure is equivalent to Australian patent no. 281537 and he recalls an incident in the United Kingdom in 1979 when he read an abstract of another application by the present inventor and immediately wondered what was new over this patent.  At the same time a colleague pointed out the relevance of U.K. patent no. 1,306,546.  He thus concludes that it was known in Australia that an explosive composition could be made by mixing a water‑in‑oil emulsion with solid ammonium nitrate.  Dr Sujansky points out that he was aware of the patents filed by Dupont de Nemours disclosing the use of gas entrapping material to enhance the sensitivity of emulsion explosives.  He asserts that the use of gas entrapping material to enhance the sensitivity of ammonium nitrate explosives was common general knowledge and refers to several Australian patents which illustrate the use of gas entrapping material.  Dr Sujansky deposes that research and development personnel of Dupont in Australia would have known about water‑in‑oil emulsions before the priority date of the present application because research and development of explosive compositions in Australia is mainly carried out by Dupont and ICI.

Dr Sujansky then compares the disclosures of the present specification with the disclosures of Australian application no. 29408/71 ‑6‑

which is equivalent to UK patent no. 1,306,546.  He alleges that the UK patent is cited in the present specification as common general knowledge.  He concludes that after reading the citation he would expect gas entrapping materials such as microballoons or plastic foam to improve the sensitivity of solid ammonium nitrate and emulsion mixtures.

Finally Dr Sujansky comments that in his experience all explosive compositions are well mixed to give as uniform a mixture as possible so as to avoid failure of propagation of the explosion due to local deficiencies in sensitivity.

Dr Hagan was Senior Mining Engineer with the Explosives Division of ICI Australia in 1977 but has subsequently left the company to work as Principal Blasting Consultant of Golder Associates.  In 1977 he had discussions with technical personnel from the Explosives Division of Canadian Industries Ltd (CIL) which is one of the ICI family of companies.  Subsequently Dr Hagan produced a report on the discussions but he has been unable to find a copy of the report so the annexure to his declaration is a memo from him to Mr J.K. Mercer.  The memo which is entitled "Technical Dialogue between C.I.L. and Atlas Powder Company On Small Diameter Water Gels" does not contain any technical details, but is concerned with the nature of the information that ICI should seek from Atlas Powder Company when it shared its knowledge with the ICI family.  I will not consider this declaration further.

The evidence in answer consists of a statutory declaration made by Dr Robert B. Clay the inventor named in the present application.  He declares that he understood that ammonium nitrate/fuel oil explosives had the disadvantages of having a relative low bulk density and no water resistance.  He also states that he had previously made emulsion blasting agents similar to those disclosed in U.S. patent no. 3,447,978.  It occurred to him that an emulsion could be added to a solid ammonium nitrate/fuel oil explosive to increase both its bulk strength and its water resistance.  The addition of a small amount of a sensitizer to the emulsion would sufficiently sensitize the resulting explosive.  After considerable experimentation Dr Clay discovered the idea did have merit and arrived at the presently claimed composition.  He states that a search in the United States patent office files turned up several related patents including US patent no. 3,161,551.  He also admits to being aware of United Kingdom ‑7‑

patent no. 1,306,546 but states he was not aware of Australian patent no. 281,537.  Dr Clay then compares the disclosures contained in these patents with the present specification.  He also states that he has attempted to repeat an example from the Australian patent and example 25 from the United Kingdom patent.

The evidence in reply consists of a further statutory declaration made by Dr Sujansky in which he describes his attempts to repeat the examples repeated by Dr Clay.

Section 40

I have previously mentioned particular problems that I found whilst interpreting the specification which result in the specification not complying with Section 40.

Dr Hinton argued that claim 1 included within its scope compositions that would not work because the proportion of gas‑trapping density reducing material was not specified in the claim whilst the description makes it clear that the density of the blasting composition is critical to its sensitivity.

Mr Waters on the other hand stated that the proportion of density reducing material in claim 1 was subject to the functional limitation that there must be sufficient of this material to sensitize the composition and improve its detonability.  He submitted that this functional requirement was necessary to allow for the variety of conditions under which the blasting agent could be used.  He further argued that the skilled person could easily determine the amount of density reducing material without conducting inventive experiments.

Mr Waters' submissions amount to an argument that the quantity of gas‑trapping density‑reducing material defined in claim 1 is claimed by result (No‑Fume Ltd. v. Frank Pitchford and Co. (1935) 52 R.P.C. 231). Therefore I have to determine whether the specification teaches the skilled person when the quantity of gas‑trapping density‑reducing material does, and does not, sensitize the composition and improve its detonability.

‑8‑

The purpose of the invention stated in the specification is to produce a water resistant blasting agent which has a density greater than water but which detonates reliably without being hazardous to handle.  Several measurements of the sensitivity and detonability of the preferred composition are reported in the specification including the bulk density, the bulk strength, the water resistance, the critical diameter, the minimum sized booster required, the detonation velocity and the storage stability.  Also the detonability of the blasting agents varied with the proportions of the components, the density of the composition and the diameter of the charge.

Although the specification does not describe the procedures used for making these measurements I consider that these procedures are routine and known in the art.  Also I consider that the specification teaches that the measurement of the sensitivity and detonability of a composition will provide enough information for the skilled person to assess whether a composition satisfies the purposes of the invention.  Therefore I am satisfied that the quantity of gas‑trapping density‑reducing material need not be specified in claim 1.

Dr Hinton also pointed out that the following statement occurs in the description:

"The water‑in‑oil emulsifiers used in the present invention are employed in very small proportions and hence must be very efficient"

whereas claim 1 contains no restriction on the amount of emulsifier employed in the blasting agent.  Mr Waters replied by arguing that it was clear from reading the specification as a whole that this statement was not describing an essential feature of the invention and suggested that the word "are" in the statement should be replaced by the words "may be".  He also submitted that the minimum amount of emulsifier would be used in manufacturing the blasting agent in order to minimise its cost.  Previously I have interpreted the emulsifier as not being an essential feature of the blasting agent, however the question of the emulsifier occurs later in this decision in the discussion of anticipation.

Dr Hinton submitted that the method of blasting defined in claim 15 would not work in the manner stated in the claim.  He argued that the borehole could only be filled up to the water level if water was trapped as ‑9‑

the blasting agent was added.  Otherwise the water level would change because the water would be continuously displaced upwards by the denser blasting agent.  After discussion with the inventor, Mr Waters stated that he had been advised that this method of blasting was being used commercially in North America.  Moreover he explained that the water level referred to in claim 15 was the level of the water table at the site of the borehole.  He stated that, after water is displaced above the level of the water table the displaced water would seep out through the side of the borehole.

The description corresponding to the method of blasting defined in claim 15 reads as follows:

"In boreholes only partly filled water, the compositions of this invention may be poured into the water until they top it or rise above its surface, after which the remainder of the borehole may be filled up to the level desired with less costly explosive, such as dry ANFO, or enriched or heavy ANFO, e.g. ANFO to which some slurry has been added but not necessarily waterproof".

This description does not support Mr Waters' interpretation of the water level whereas Dr Hinton's explanation appears to be correct.  However I notice that Dr Sujansky did not comment on this aspect of the invention.  Therefore I consider that the method of blasting is described and claimed in terms which are readily understood by the skilled person.

Obviousness

Dr Hinton made several submissions under this heading based on Dr Sujansky's declaration, however it is not necessary for me to detail them in view of my previous summary of this declaration.

Mr Waters in response drew my attention to the law set out in Minnesota Mining and Manufacturing Co and 3M Australia Pty Ltd v Bieirsdorf Ltd 29 ALR 29 at pages 57 and 58 and Graham Hart Pty Ltd v S.W. Hart Pty Ltd 18 ALR 625 at pages 634 and 636; ie that evidence in support of the objection of obviousness has to come from common general knowledge in the art in Australia. He pointed out that this was not the situation in the present oppositon as all that Dr Sujansky's declaration established was his own personal knowledge rather than what was common general knowledge. He ‑10‑

also refuted Dr Sujansky's argument that British patent no. 1,306,546 was acknowledged as common general knowledge in the specification.  In particular Mr Waters stated that the law which he cited demonstrated that common general knowledge was matter which was used in an art.  He submitted that there was no evidence that the compositions described in British patent no. 1,306,546 had been used in Australia. 

I agree entirely with Mr Waters' submissions on this matter and will say no more on it.

Anticipation

Dr Hinton made submissions under this heading only with respect to British patent no. 1,306,546, which is equivalent to Australian patent application no. 29408/71 and which was published on 30 November, 1973.  I agree that the other citations considered by Dr. Sujansky do not disclose the combination of features listed in the present claim 1.  Dr. Hinton's arguments were that the features of the present claim 1 were anticipated by the disclosures of application no. 29408/71, that of the remaining claims only claim 9 introduced a feature that was surprising and that any differences in the remaining claims were mere workshop improvements.  Mr Waters submitted that the present claims were a selection from the broad disclosures of the citation.  He claimed that the specification stated that the advantages gained by the selection were as follows:

"The advantages of this invention are important in cost, bulk density, bulk strength, water resistance, and in detonation velocities".

He also pointed out that the claims selected a specific range of weight per cent for the emulsion and the solid and also selected a gas trapping density reducing material as the sensitizer in the emulsion.

The specification of Australian application no. 29408/71 states that the invention relates to a substantially waterproof blasting explosive composition with a grease‑like consistency.  The object of the invention is to produce blasting explosive that can be loaded directly into a water‑filled borehole without being deleteriously affected by the water and having a viscosity sufficiently high to substantially prevent segregation ‑11‑

of any solids present but sufficiently low enough to allow the explosive to be poured or pumped into boreholes.  Then follows a description of the invention in identical terms to those of claim 1 and the density of the composition is stated to normally lie in the range of 0.3 to 1.7 g./cc.  Then there is a more detailed description of each of the components of the composition which includes a description of non explosive sensitizers as both particles containing an entrapped gas eg phenolic resin microballoons and gas bubbles produced in situ eg from hydrogen peroxide.

The description continues that the blasting composition of the invention may contain one or more solid particulate oxygen‑releasable substances dispersed in the grease and gives ammonium nitrate as an example.  When a solid particulate oxygen releasable substance is incorporated in the grease it is preferable to provide additional fuel material so as to keep the overall oxygen balance of the composition near to zero.  Such additional fuel may be an additional quantity of the non explosive hydrocarbon fuel or a quantity of non‑explosive sensitizer or mixtures of these substances.

The amount of solid oxygen‑releasable substance present in the blasting explosive composition is normally between 0 and 70% by weight of the total composition.  Where 50% by weight of the total composition consists of porous prilled ammonium nitrate and fuel oil incorporated in the grease, it is possible for this mixture to act as the sole sensitizer when the blasting composition is used in boreholes at least 4 inches in diameter.

Example 24 is a composition in which 30% by weight of fertiliser grade ammonium nitrate prills are stirred into a grease sensitized with hydrogen peroxide.  Example 25 is a composition in which 56% by weight of a mixture of ammonium nitrate porous prills are incorporated into a grease containing no other sensitizer.  There are also other examples of grease‑like compositions in which the sensitizer hydrogen peroxide is replaced by phenolic resin microballoons or hollow glass spheres.

The relevant claims read as follows:

1. A blasting explosive composition having a grease‑like consistency comprising at least one water‑soluble inorganic oxygen‑releasable salt, at least one substantially water‑insoluble non‑self‑explosive hydrocarbon or halogenated hydrocarbon fuel, ‑12‑

water, a surfactant capable of imparting a grease‑like consistency to the composition, and at least one sensitizer distributed substantially homogeneously throughout the composition in an amount sufficient to sensitize the composition.

1. A composition as claimed in any preceding claim, wherein the surfactant is present in an amount of from 0.5 to 15% by weight of the total composition.

1. A composition as claimed in any preceding claim, wherein the sensitizer is a non‑self‑explosive sensitizer.

1. A composition as claimed in Claim 14, wherein the sensitizer is a gaseous sensitizer present in the composition in the form of gas bubbles or discrete particles containing entrapped gas.

1. A composition as claimed in any preceding claim and further comprising one or more solid particulate oxygen‑releasable substances dispersed therein.

1. A composition as claimed in Claim 22, 23 or 24, wherein said substance is present in an amount of up to 70% by weight of the total composition."

Some of the blasting agents defined in the present claims lie within the scope of the composition defined in claim 25 of the citation. However the citation does not disclose a specific example of a composition that lies within the scope of the claims. In this regard the claims are in a position to be considered as a selection from the citation as argued by Mr Waters. A requirement for a selection patent is the discovery that one or more members of a previously known class of products possess some special advantage for a particular purpose, which could not be predicted before the discovery was made (Beecham Group Ltd. v Bristol Laboratories International S.A. (1978) R.P.C. 521 at p 579). The present specification states that the compositions described in the citation required the addition of hydrogen peroxide and/or other sensitizers, required the use of large propertions of emulsifier and could not be used in deep boreholes without adding density reducing material. However the advantages alluded to by Mr Waters do not include solutions to any of these problems but are a list of desirable properties for any explosive composition. In the specification the advantages referred to by Mr Waters follow a comparison between the present blasting agent and a conventional ammonium nitrate/fuel oil explosive. Because the citation is discussed elsewhere in the specification I consider that the statement relied on by Mr Waters only supports the view that the present blasting agent has advantages compared ‑13‑

to a conventional ammonium nitrate/fuel oil explosive.  Therefore I do not consider that the present claims are a selection from the citation because there is no discovery of special advantages for a particular purpose.

The question I have to consider with respect to anticipation is whether the citation discloses all the integers of the blasting agent claimed in the present claims (Dennison Manufacturing Company v Monarch Marking Systems Inc (1984) 1 I.P.R. 431 at p.452). I consider that Claim 1 in suit is anticipated by claim 25 of the citation in so far as the blasting agent which it claims contains an emulsifier or surfactant. Similarly claims 2 to 8, 10 and 12 to 15 are anticipated because I consider the features added by these claims would require no more than the knowledge possessed by the skilled person in the art. However claims 9 and 11 are in a different situation because I consider the skilled person would have to rely on the teaching of the citation for guidance in the amount of emulsifier to use. Although claim 1 of the citation does not specify a particular amount of surfactant, claim 13 claims an amount of from 0.5 to 15% by weight of the total composition and the amount preferred in the specific embodiments is from 1 to 5% by weight of the total composition. I consider that the teaching of the citation is away from the small quantity of a restricted range of emulsifiers claimed in claims 9 and 11 in suit. I note that both Dr Hinton and Dr Sujansky conceded that the small amount of emulsifier was surprising. I therefore find that claims 9 and 11 are not anticipated by the citation.

Conclusion

In summary therefore I find that the specification does not comply with Section 40 and that claims 1 to 8, 10 and 12 to 15 have been anticipated by Australian application no. 29408/71.  I am satisfied that there is patentable subject matter disclosed in the specification and for this reason I allow the applicant 60 days from the date of this decision in which to lodge amendments to my satisfaction.  I award costs against the applicant Robert B. Clay.

(J.L. ROVETA)