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This paper deals with the application of table flotation to two unusual mineral dressing problems. Both problems involved the removal of interfering minerals at sizes too coarse to normal froth flotation.The first problem was the removal of arsenical minerals from Broken Hill gravity concentrates without further size reduction. Table flotation without grinding of the original concentrates gave almost complete rejection of the arsenic from the concentrates. A typical test result was a reduction of arsenic in jig concentrate from 0.75% arsenic to 0.007% arsenic.The second problem was to develop a method to produce a high grade calcium carbonate concentrate from coastal dune sands containing about 10% silica and about 80% calcium carbonate. The sands were about 30 mesh British Standard Screen (B.S.S.), and for economic and other reasons it was stipulated that the separation be made without grinding. Again, table flotation gave excellent results. A concentrate was produced containing 99.62% acid soluble material, representing a recovery of 98.69% of the calcium carbonate in the feed with a rejection of 96.44% of the silica.The investigations' were carried out at the Kalgoorlie Metallurgical Laboratory, under the Department of Mines...

Jan 1, 1954

The paper is a general review of practice in design of sub-level open stopes in Northern Rhodesian copper mines and gives examples of some interesting developments during the last five or six years. It discusses the effect of hangingwall subsidence and the methods used to combat rock pressure on working areas.INTRODUCTIONAll producing mines on the Northern Rhodesian Copperbelt have large ore reserves and are designed for high rates of production. The three mines (Mufulira, Rhokana Corporation, and Roan Antelope) where sub-level open stoping is used, hoist from 250,000 to over 400,000 short tons of ore a month so that any stoping method used must be adaptable to concentrated' mining. Individqal stopes produce from 5,000 to over 25,000 short tons of ore a month.Structure af the ore bearing sediments is simple; faulting in ore is almost entirely absent and copper mineralisation is found in the same beds over great distances...

Jan 1, 1954

Since the end of World War n, many important developments have taken place in the investigation of the phenomenon of brittle fracture in mild steel. Fractures in certain classes of welded ships, in welded bridges, penstocks, etc., focussed a great deal of attention on the interrelationships of design factors, service conditions, and steel quality on the generation of catastrophic failures.Much publicity has been given these major failures, and there is perhaps a tendency to forget that mild steel, under certain conditions, as well known to behave in a brittle fashion in a wide range of everyday engineering applications.For instance, many who are connected with the haulage and lifting of heavy loads will be familiar with the bright "crystalline" fractures of crane hooks and chains which sometimes follow sudden jarring; those concerned with the heavy pressing and shaping of steel plate will not be unaware that at times sudden brittle splits or tears will develop for no obvious reason in, say, rolled pipes or in dishings.In fact it will be evident upon reflection that in many cases the conditions which mild steel has to withstand during processing into an engineering part or structure are more severe than those it wili be called upon to endure during service. In this sense brittle fractu;res in mild steel are much more frequent than are commonly supposed.Two modes of fracture are now generally recognised to occur in metals, namely, shear and cleavage. The latter manifests itself by the so-called "crystalline" fracture (here...

Jan 1, 1954

Experiments in the bolting of a mine roof were commenced at Elrington Colliery on the South Maitland Coal Field early in 1949, following the appearance of an article in the American publication, "Coal Mine Modernisation Year Book" 1948. Prior to this, although bolting had not been used in the maintenance of satisfactory roof conditions, the principle of roof bolt anchorage had been illustrated in instances such as the hanging of a trolley locomotive power wire using an expanding shell type of bolt anchorage, or the insertion of an eye bolt with a split and wedge, as used to suspend a rope block over a winze being sunk in a metalliferous mine.The experiments at Elrington Colliery were the first efforts in this country to supplement the work of timber supports under a mine roof with systematic placement of roof bolts.Following the series of experiments at Elrington, full scale bolting was commenced at that Colliery in a trackless mobile section in April, 1950.The obvious success of the system at Elrington indicated that it might also be a success in the support of weak roof strata immediately overlying the workable section of the Victoria Tunnel Seam at John Darling Colliery.The system was commenced at John Darling Colliery in April, 1951, in one mechanical section on the Victoria Tunnel Seam, and the scope was gradually widened until by December, 1952, ail'six mechanical units then operating on this seam were working under bolted roofs.

Jan 1, 1954

In preparing a paper such as this it was thought that the Newstan Colliery Company Ltd., being comparatively new, would need some introduction to mining people in general.The Newstan Company was formed by the Joint Coal Board in December, 1948 during a period of acute coal shortages. The Company took over the holdings of what were known as the Olstan and Northumberland Collieries, situated at Fassifern, alongside Lake Macquarie and adjacent to the Great Northern Railway, within easy rail access of Sydney and Newcastle, as shown on the locality plan (Fig. 1).The Company was developed in order to produce steaming coal for the power house trade and has continued its activities in the steaming coal trade since its inception. The Olstan and Northumberland collieries were together producing some 300 tons per day when the Company was formed, and it was from this foundation that the colliery was built. The planned development of the Company has been along the lines of producing coal by modern, highly mechanised methods, together with the preparation of theproduct for the consumer, to the highest degree possible consistent with up to date methods.In the comparatively short time of 5t years the mine has developed from a small hand-won coal unit to a high capacity modern mine, one of Australia's largest producers, with an output capacity as high as 3,000 tons per shift.

Jan 1, 1954

The beach sand industry is the only Australian mineral industry which, so far, has used electrostatic separation on a full commercial scale. The main application of the process is for the separation of rutile from zircon. Laboratory work has demonstrated that electrostatic methods are effective for ilmenite-monazite and cassiterite-zircon separations, thus facilitating the production of high grade monazite and cassiterite products from top-strip table concentrates, but the commercial application of these processeshas been rather limited so far. Overseas, electrostatic methods are becoming more widely used for the treatment of granular material which is not amenable to flotation. The use of electrostatic separation for the treatment of ores other than beach sands has been investigated in this laboratory 1, 2, 3, and two pilot separators were built during i953 to carry out field tests. Of these, the first was an inclined feed plate separator for the removal of silica from granular lime-sand in Western Australia, the second a conductance roll separator for the removal of diamonds from alluvial gravel in New South Wales. In both cases the whole of the ore passed through the separator, not a gravity concentrate only as in beach sand practice. The two types of separator mentioned are shown diagramatically in Figs. 1 and 2.

Jan 1, 1954

Small scale' table concentration tests have many critics. Many metallurgists consider that such tests are of problematical value because of the difficulties involved in conducting and interpreting them.Many kinds of small-scale ore dressing tests are difficult to conduct, and there is, perhaps, good reason for thinking that table concentration tests are amongst the most difficuIt.Interpretation of results from small-scale tests is the responsibility of the metallurgists and engineers in charge, and it is often held that small-scale table concentration tests are particularly difficmlt to interpret.TESTING FOR TABLE CONCENTRATIONOn analysis it appears that the difficulties encountered in conducting small-scale table concentration tests are of three fairly distinct kinds. Firstly, there are difficulties due inherently to the smallscale nature of the operations; for example the smaller width of all mineral bands on the table and the less complete separation due to the shorter length of travel between the feed and discharge points.Secondly, there are the effects of batch operation owing to the fact that the mineral particles behave differently during the initial period when the sample is just beginning to spread over the table, the middle period when feed and discharge are even and continuous, and the final stage, when the last of the sample has been added and the table is beginning to empty itself.

Jan 1, 1954

Delivered at the University of Sydney, on June 4th, 1954.THE TORCH WE HOLDLast year Our Institute celebrated its Diamond Jubilee, coincident with the holding of the Fifth Empire Mining and Metallurigcal Congress in Australia and New Zealand. We can be proud of our growth over the 61 years since the inaugural meeting in Adelaide in April, 1893, which followed suggestions from a provisional committee of mining men, formed in 1892 in Broken Hill.We can also be proud of our technical achievements in the fields of economic geology, mining and metallurgy.Should we be content with the growth of our mining and metallurgical industries over these years? My answer is in the negative. The discovery of new mineral deposits is essential for the continuance and development of the industries we represent.Let me review the background and trends of our industry in an attempt to emphasise the changing factors influencing the search for minerals and their exploitation.Australia was blessed with the discovery of coal in New South Wales in 1796; copper in South Australia at Kapunda, Burra, Wallaroo and Moonta in the eighteen-forties; gold in Victoria and Eastern Australia in the 'fifties; tin at Mount Bischoff, Tasmania, and gold at Charters Towers, Queensland, in the 'seventies; lead-silver at Broken Hill, New South Wales; gold and copper at Mount Morgan, Queensland, and copper at Mount Lyell, Tasmania, in the 'eighties; and gold at Kalgoorlie, Western Australia, and zinc-lead atRosebery, Tasmania, in the 'nineties. As well, the iron ore deposits of the Middleback Ranges, South Australia, and Yampi Sound, Western Australia, were known before...

Jan 1, 1954

The purpose of this paper is to cover in a general way the extent, geology, quality of product, working methods and trials of the coal mining industry. of New South Wales from 1946 to the present day, with particular reference to the Western field.It must be clearly understood that any opinions expressed are those of the author and not necessarily those of the Joint Coal Board.The extent of the Western coal field at the present stage of investigation may be said to be from a few miles east of Katoomha to a few miles north-west of the township of Ulan, the total distance being 150 miles.To the west of a line from the Western Highway from Lithgow through Wallerawang, PortIand, Tyldesley, Ben Bullen, Kandos and Rylstone, there are no signs of coal except for one or two outiiers in the neighbourhood of Portland. To the east of this line the coal-bearing areas extend to the seaboard approximately 80 miles to the east.GEOLOGY AND CHARACTERISTICS OF THE COAL SEAMSThe Western coal measures belong to the Upper or Newcastle series, which have been correlated with the Sciritheru or lllawarra, and the North-western or Gunnedah measures. Being close to the margin of the coal basin the Western measures have an average thickness of only 200 ft. to 500 ft., or approximately one-half of the maximum development of the Newcastle measures. They are underlain by Upper Marine beds which in turn rest directly on Devonian rocks.

Jan 1, 1954

By Dunkin H. H

Flotation tests in a laboratory flotation cell at pH 8-8.5 and other sui}plementary tests were carried out on sphalerite-quartz and sphalerite-pyrite-'quartz mixtures. Depression of sphalerite resulted vvhen the addition of copper sulphate exceeded an optimum value. Evidence that this depression was due to collector deficiency because of reaction between copper sulphate and collector is presented. It was not found possible to devise a direct analytical method suitable for .plant control of reagent addition. A possible means of control using potassium cyanide and a higher pH is discussed.INTRODUCTIONAt the Rosebery mill of Electrolytic Zinc Co. of Australasia Ltd., recovery 'of sphalerite in the zinc concentrate occasionally drops unexpectedly. Experiment in the mill and mill laboratory has suggested that one of the factors causing this may be the addition of more than an optimum amount of copper sulphate. On such occasions, an increase in the collector addition improves zinc recovery in the zinc concentrate, but only at the expense of sphalerite-pyrite selectivity.To examine the phenomenon more thoroughly, and if possible to find some means of determining the optimum addition of cepper sulphate and controlling the actual addition at this optimum, one of the authors (W. J. T.) was employed by the Electrolytic Zinc Co. of Australasia' to carry out investigations in the Mining Department, University of Melbourne, under the joint direction of R. B...

Jan 1, 1954

Introduction.History of Stope Filling at Mount Isa.The Need for a Systematic Fill Programme.Reasons for Filling.Fill Materials and Tonnages.Rough Mullock Fill.Quantities Readily Available.Fill Pass Development.Stope Preparation.Drainage.Hydraulic Sand Fill.Initial Experiments with Mill Tailings.Surface Layout.Operation Procedure.Underground Pipe Lines.Life of Sand Pipes and Cones.Drainage.Old Tailings Dam Sands.Quantity of Fill Placed.Pillar Tonnages.Conclusion and Acknowledgment.INTRODUCTIONFilling practice outlined in this paper refers exclusively to the Black Star section of the mine. The stope filling necessary early in the life of the Black Rock and portions of the Rio Grande sections is not to be confused with the current filling programme.

Jan 1, 1953

The primary object of this paper is to describe the present metallurgical practice of the Emperor Combined Mill, wherein ores from the adjoining and Associated Mining Companies, Emperor Gold Mining Company Ltd., Loloma (Fiji) Gold Mines, N.L., and Dolphin Mines, Ltd., are treated for the recovery of gold and silver.The mining field is located in the foothills, five miles from the sea, on the northern side of Viti Levu, the largest and most important island of the Fiji group.The orebodies occur in basalt and associated ash beds overlain by andesite, tuffs and sediments. The basalt is a dark greenish-black rock and in much of the ore mined is weathered with alteration of the olivine to serpentine and iron oxides, of the augite to chlorite and of the minute included crystals of iron ore to other iron oxides. Into the basalt intrudes a considerable number of andesite dykes, and the lodes occur as veins in these dykes, as "flatmakes" along fissures or, ash beds extending horizontally from the dykes and at the contact of the basalt and the andesite dices.The Emperor orebody is the largest and most important, and consists essentially of massive, shattered, well altered and mineralized basalt.Little or no free gold occurs in the ore at present being milled, the most important host minerals for gold being the tellurides sylvanite and hessite, next in importance being the sulphides, pyrite, marcasite and arsenopyrite. Chalcopyrite is present in quantities large enough to be troublesome in the subsequent concentrate treatment section, while sphalerite, tetrahedrite, bornite, galena and native tellurium are present in small quantities.Unimportant occurrences of native copper have been observed in both Dolphin and Emperor orebodies.

Jan 1, 1953

I have chosen this topic for my address with the intention of preserving a rather extraordinary record of recurrent additions of capital in the financing of one of the world's important silver-lead-zinc mines. The recitation of the trials and tribulations which fore-shadowed the rise of Mount Isa Mines to a position of relative prominence in the realm of non-ferrous mineral production may, I hope, be of assistance to some of the younger members of the Institute who may be called upon during their careers to meet similardevelopmental and financial problems.Mount Isa Mines Limited was incorporated in New South Wales in 1924 with an Authorised Capital of 40,000 shares of £20 each.In November 1925 the Company acquired the leases and water rights of the Mount Isa Proprietary Silver-Lead Limited for 6,250 fully paid £20 shares. Shortly thereafter, but in the same year, the £20 shares were split up into £1 shares, thus bringing the Authorised Capital to £800,000.The leases purchased consolidated and brought under one management the principal ore bodies of the Mount Isa area.Transportation facilities were indispensable to the economic future of the field, so the construction of a railway extending the Government line from Duchess, 54 ,miles to Mo.unt Isa, was assured by the passage of a bill in October 1925 by the Queensland Parliament. Under the provisions of the so-called Mount Isa Railway Act the Company was required to idemnify the Government against national loss on this branch line for a period of 10 years.

Jan 1, 1953

In the years prior to the outbreak of war in 1939 Australia's production of copper had declined from a peak of about 80,000 tons in 1911-1915 to approximately 25,000 tons in 1939. This production met the need of the slowly growing national requirement and gave an excess for export. However, with the intensification of the war effort in 1942 due to the imminence of a Japanese invasion of this country, or at least a blockade of the sea lanes, it became necessary to expand production of armaments, and consequently the demand for copper increased beyond the capacity of the industry. Importation of copper to Australia during the period 1940-1944 was 131,000 tons.When exploration of the Mount Isa orebody was first being carried out in 1928, No. ID diamond drill disclosed the presence of some copper ore lying outside the limits of the Black Star orebody2, but it was not until 1941-1942 that the development of No. 7 level in the Black Star orebody enabled the existence of a lode of copper ore of economic grade to be established. At the request of the Commonwealth Government of the day a programme of development for copper production was undertaken whilst lead smelting was continued as before the war.A series of flotation tests on up to 1,500 tons of ore at a time, was undertaken and the concentrate so obtained was stockpiled. These tests were conducted, using one section of the lead mill, and demonstrated that a concentrate grade of 22-23% Cu with a recovery of 80-85% might be expected.These recovery figures were afterwards much improved, and 93-95%was obtained before the close of smelting in 1946.

Jan 1, 1953

Delivered by K. B. Gross at the First Ordinary Meeting of the Australasian Institute of Mining and Metallurgy, August 18th, 1952.Mr. President, Ladies and Gentlemen:Confronted with the task of reviewing the progress of Mount Isa Mines Limited, since the inception of the Company 28 years ago, I soon found that effective coverage was a task beyohd me, if I were to confine the address within the limits of time allowable. Faced with the alternative, a summary, that could only fail to -do justice to the subject, I turned elsewherl? for inspiration and found it in Chester Wilmot's book "The Struggle for Europe". Those of you who have read this masterly contribution to the literature of World War II will recall that he takes us, most dramatically, behind the scenes and we learn of the thoughts and ideas that were uppermost in the minds of both allied and enemy leaders at times when decision's that profoundly influenced the course of the war were taken. I felt I could safely follow this rather novel approach to my own problem. Strengthened by the realisation that the technical achievements of the Company have largely been covered over the years, and that the results of our labours are mainly here before you, I have attempted to liven up my modest canvas by going behind the scenes, and have sought to deal with ideas and the reasons for important decisions, rather. than to embark upon a purely descriptive essay.If then, you will bear with me, we shall skip back through the years to the days of struggle that our President's address has so aptly covered, and find that one man's ideas and faith stand out beyond all others. W. H. Corbould must always be credited with having founded the enterprise, for he correctly appraised the potential of the struggling prospect and foresaw what could be done, despite the handicaps of geography, climate and need for heavy expenditure.

Jan 1, 1953

The silver-lead ores of Yerranderie occur in a series of narrow, flat-dipping lodes in small bodies of quartz porphyry, intrusive into Upper Devonian volcanics, which are exposed in the western flank of the Permo-Triassic Basin of central New South Wales, about 80 miles south-west of Sydney (Harper, 1930; Lawrence, 1953). The lodes strike about E.-W. and are from 1,200ft. to 2,000ft. long. They consist of a series of ore shoots from 3ft. to 100ft. long, and up to 5ft. thick, though commonly under 2ft. thick, interspaced with low grade sections. They dip at from 18°S. to 400 S., and have persisted down the dip for 1,450ft. (693ft. vertical depth) in the Wollondilly mine, for 1,120ft. in the Bartlett's mine, and for 850ft. in the Wonga mine.The grade of ore in the Bartlett's mine was from 32% to 40% lead, from 100 oz. to 130 oz. silver per ton, 0.5 to 4.0% arsenic, with ore ,as rich as 20% arsenic on the No. 6 and No. 7 levels of the Silver Peak mine, the underlay extension of the Bartlett's lode, about 1% copper, and up to 4 dwt. gold per ton. In the Wollondilly mine the average grade was 15% lead, with sections as rich" as 36% lead, from 75 to 165 oz. silver per ton, 0.6 to 3.3% arsenic, 0.2 to 0.7% antimony, 0.8% copper, and up to 7...5. Cl~t. gold per ton. The zinc content of the ores is slight, and has not been recorded.Mining began about 1898, and to date more than 110,000 tons of ore, valued at £1,800,000, has been raised. Large scale mining ceased about 1935. The chief mines operating were the Bartlett's mine (formerly Colon Peak), the Silver Peaks, which is the underlay extension of the Bartlett's, the Wollondilly (or Yerranderie) mine, and the Wonga' (or Tonalli) mine.

Jan 1, 1953

The equipment and general smelter layout for the Mount Isa Copper Smelter were designed by engineers associated with the American Smelting and Refining Company and by Mount Isa staff engineers. The final notice of site was dictated by the need for 'building the smelter near the existing Mount Isa power house to enable full use to be made of the steam from the waste heat boilers. Although much excavation work was necessary before concrete foundations could be poured, the location lends itself to further expansion should it become necessary. The plant is designed and constructed to involve straight line smelting operations which include the following major steps in the overall scheme.1. Charge make-up.2. Roasthig.3. Reverberatory smelting.4. Converting.5. Refining.6. Casting.CHARGE MAKE-UPA system of proportioning bins is provided for preparing the feed mixture for the roasters, Sulphide concentrate containing 24% copper wiil be delivered by belt conveyor from the filter plant to the smelter storage patio. This is a large roofed concrete floor that provides a maximum storage capacity of 8,000 tons of concentrate. Eight proportioning bins located below but adjacent to the south end of the patio will be used for actual charge make-up from which concentrate, ore and flux will be proportioned to the feed belt and conveyed to the roaster feed hoppers. Four of the proportioning bins, 80 tons capacity each, will receive...

Jan 1, 1953

This paper aims to provide some' new and original thoughts on tungsten carbide drill-bits and describe practices and performances, some of which are unique and most of which have not previously been described. Many theoretical and descriptive papers and articles on carbide bits have appeared during the last few years, and in the big majority conclusions such as these were made. These results are marked by premature failure of the bits, or The full or economic life of the bit is seldom reached due to the premature failure of the insert. Unfortunately those conclusions are seldom accompanied by the reasons for premature failure. In the few cases where reasons for failure have been advanced, very little, originality has been shown. The reasons usually given are that the failures are due to bad operators, bad workmanship, faulty steel or unsuitable machines, but it has been shown at Mount Isa that the chief reason for poor performnce is bad design.The first question asked will be, "What is wrong with the design of most bits?" and the answer'is, "The size of' the inserts". There may be many other small faults iiI different types of bit but Mount Isa experience indicates that the size of the insert is the most important factor influencing pit life. Under normal conditions it has been found, that there is a minimum size of insert that will give satisfactory performance, and this minimum is 5/16 in width and ? in. depth at the shoulder. A big majority of the bits at presentavailable in Australia do not satisfy these requirements.

Jan 1, 1953

The Ravensworth-Liddell area is part of the Muswellbrook- Singleton Coal District of the Northern Coalfield. It lies in the Parishes of Liddell, Ravensworth, Vane and Howick, in the County of Durham, midway between Singleton and Muswellbrook, and is traversed by the Great Northern Railway, and the New England Highway.Ravensworth and Liddell railway stations are 57 miles arid 61 miles, respectively, north from Newcastle (Fig. 1).The area has been the centre of an intensive search for open cut coal during the past few years. More than 1,200 bores, of which about 10% were cored diamond drill holes, were drilled to depths of about 200ft. Portions with thicker cover have been explored by 10 diamond drill holes to depths of over 400ft. but core recovery from these deeper holes was poor, and the lack of detail in the recorded logs limits geological interpretation. The drilling has proved about 34,000,000 tons of open cut coal, and about 246,000,000 tons under deeper cover.GEOLOGYThe Ravensworth-Liddell area lies on the eastern flank and southern extremity of the Muswellbrook Dome, extending from Hebden in the north, to Jerry's Plains in the south, and the rocks under consideration belong to the Tomago Stage of the Upper Coal Measures. On the north they are truncated by the Hebden Thrust fault, which has a throw of about 4,500ft. (Raggatt, 1929). On the west they are bounded by outcrops of the Upper Marine Series, which conformably underlies the Upper Coal Measures, and...

Jan 1, 1953

Vatukoula is credited with the second largest population in the Colony of Fiji. Within an area comprising 550 acres are living approximately 4,500 people. Of these, about 1,150 Fijians, 90 Rotumans, 90 Europeans, 180 Part-Europeans, 180 Indians and 30 Chinese and miscellaneous Pacific islanders are employees of the Associated Mining Companies.The remainder is made up of employees dependants with a small minority of tradespeople and Government servants, such as storekeepers, school teachers, police and post office officials.To appreciate fully the work involved in the administration of this unusual community it is necessary firstly to know something about the various types of people which compose it.The FijiansAlthough the Fijians are of Melanesian stock their physical characteristics indicate a Polynesian strain. Natives from all provinces in the Colony are to be found in Vatukoula and their varied types point to this MelanesianPolynesian intermixture. For example, there are people from Lau** and Kadavu who are tall and well built with good features and comparatively fair skins contrasting with the dark, broad featured and generally short people of the hill tribes of Ra and the coastal tribes of Bua.The Fijians, particularly the older people, are noted for their dignity, courtesy and hospitality. The young Fijians of the present generation, large numbers of whom are...

Jan 1, 1953