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By G. R. Hopkins

According to reports as of January 1, 1931, the total daily charging capacity of the cracking plants, hoth completed and under construction, in the United States amounted to 1,950,781 "barrels, an increase over the previous year of 14 per cent. The total daily capacity of the operating plants amounted to 1,594,990 "barrels, or 82 per cent of the grand total, the capacity of the in¬ operative plants was 244,661 "barrels, or 12 per cent of the total, while the capacity of the plants under construction amounted to 111,130 "barrels, or 6 per cent. In comparison with a year ago, these data indicate a decline in the total capacity of the plants "being "built "but show material increases in the capacity of "both the other two classes. The increase in total inoperative capacity and the decline in construction in 1930 undoubtedly resulted from un¬ satisfactory economic conditions. The total number of cracking units completed or under construction on January 1, 1931, totaled 1,863 as compared with 2,002 the previous year and with a high of 2,559 on June 1, 1926. During the period between June 1, 1926, and January 1, 1931, the total charging capacity of the cracking plants has more than doubled, but the number of units has shown a material decline. This condi¬ tion has been brought about largely through the dismantling of many Burton still of small capacity and through the tendency to increase the size of the new units The "largest unit that can be identified in this survey has a daily charging capacity of 10,000 barrels, but undoubtedly there are some that would exceed this in size. Texas, with a total of 575,300 barrels, ranked far ahead of the other States in charging capacity, and was followed in order by California, Indiana, Oklahoma, and Pennsylvania. Indiana, with only five refineries, ranked third in cracking capacity, which illustrates the importance of the Chicago district as a gasoline-producing center. Not all of the States showed a gain in capacity during the year; in fact, four of them, namely Illinois, Louisiana, New York, and Oklahoma, reported a decline.

Jun 1, 1931

By J. H. Rose

This paper describing the milling practice at the Magma Copper Co., Superior, Ariz., is one of a series being prepared by the Bureau of Mines on milling methods and costs in the various mining districts throughout the United States. ACKNOWLEDGMENT The authors wish to acknowledge their indebtedness to William Koerner, general manager of the Magma Copper Co., for permission to prepare this article; to J. S. Garrott, former mill superintendent, for the historical facts; and to Walter Cooksley, general foreman, for his assistance in obtaining the data.

Jan 1, 1930

By Ian MacGregor

As I drove in from the airport on Sunday somebody said 'On the right you will see Duntroon, which is the military training school of Australia.' So I asked the driver, where did they get that name? 'Oh,' he said, 'from some people who built a house there. That was it's name- Duntroon.' It strikes a note with me because, that's the name of a 12th century castle on the west coast of Scotland where I spend what leisure hours I have and, therefore, it establishes the long connection between Australia and my native land. There is also a story I should tell you about the oil industry and its upsurge in Scotland recently which has resulted in great prosperity. And in Edinburgh, the walls of the banks are bulging-because of the incursion of foreign exchange and other resources. Charlotte Square, as some of you know, is the centre of the Scottish financial world and at one of the corners of Charlotte Square, where ho streets intersect, there are three stores-three emporia on the ground floor. Two of them at opposite corners are banks: The Royal Bank of Scotland, and not to be beaten by that, The Bank of Scotland. But the third building is occupied, or was occupied, by a furniture store over many years-very high-grade, high quality furniture that the elite of the Edinburgh society always supported. And suddenly, the store was cleared out and in came a bunch of carpenters and other people busily engaged in rebuilding the store, and finally the new tenants arrived on the scene.

Jan 1, 1978

By C. Villaseca, F. Penna, R. Villarroel

Acid mist is the undesired result of copper electro-winning (EW) process, generating a contaminated and hazardous environment in the working areas, as well as promoting high corrosion conditions for structures and equipment in the EW tank-house due to the buoyancy of sulfuric acid in aerosol form. Likewise, organic entrainments that occasionally occur in this process contaminate the cathodes, as well as increasing the risk of fire. LateralVex® and LateralFlow® are technologies that effectively and efficiently solve these problems, without affecting the usual activities of the operators, thus presenting a significant distinction with respect to other technologies that seek to solve these problems. Minera Antucoya, an AMSA group company, which produces 80,000 tons of electrolytic Cu per year, decided to install both technologies for its EW tank-house, LateralVex® in commercial cells and LateralFlow® in scavenger cells to keep both the acid mist and the organic entrainments under control. This paper presents the effects of applying these technologies in Minera Antucoya’s electro-winning plant, the challenges addressed, the difficulties encountered, the problems and opportunities that their implementation involved, as well as the surprising results obtained at the time of measuring the acid mist— less than one hundred’s part of the Allowed Weighted Limit—in samples taken with the plant operating at maximum current capacity. Additionally, the paper includes some of the improvements identified during the period, more than 3 years, in which these technologies have been in operation in Minera Antucoya. INTRODUCTION Electrowinning is the most used electro-chemical process in the hydrometallurgical industry for the recovery of highly pure metallic copper as its final product, which is formed in previous stages in an aqueous medium that goes through a selective process using organic solvents to separate impurities and concentrate the metal in a sulfuric acid solution. In the last stage, this solution goes through a process in which high- density current at a low voltage is applied, so that the metal in the solution will deposit in solid state on a plate, usually a stainless-steel plate. This last process involves the generation of other sub-products due to the electro-chemical dissociation of the electrolyte’s components, or to the addition of chemical additives, or due to specific physical conditions or lack of controls during the operation.

Jan 1, 2019

By P. Dhar, H. R. Kota, M. Thornhill

A very high-grade calcite deposit located in northern Norway consists of CaCO3 ore with minor silicate and sulphide impurities. Cationic (Tallow-1,3-diaminopropane, Duomeen T) collector has been used in the purification of calcite by flotation with an aim of achieving calcite concentrate for its use in value-added products in a variety of industries. The feasibility of sulphide flotation from calcite by this cationic collector has been initially judged from Hallimond flotation and zeta potential on pure mineral systems and the results illustrate the removal of sulphide from calcite ore at neutral pH region. The adsorption mechanism of diamine on both the sulphide minerals was found to be the same by zeta potential studies. The variations in zeta potential are in good agreement with the adsorption of diamine molecular and ionic species as a function of pH. FTIR studies also showed the adsorption of diamine species in agreement with the zeta potential and Hallimond flotation results. Furthermore, the removal of sulphide impurities with selective flotation by diamine collector was performed in bench-scale flotation with the calcite ore and the results indeed showed that the calcite concentrate could meet the quality requirements for its use in the paper industry for coating and filler purposes.

The Project ? $1.4 billion project ? 59,000 tonnes of nickel and cobalt ? Large resource base ? First production end of 2004 The Place ? Half the size of Vancouver Island ? Population 210,000 ? 43% Melanesian, 37% European, 12% other South Pacific groups, 8% other nationalities ? Tourism principal industry ? 1/3 of world?s nickel resources The Politics ? French Overseas Territory ?1998 Noumea Accord: increased local control over domestic policy ? Referendum on independence in 2014 ? Seeking more economic autonomy, less dependence on French support

May 1, 2002

By Waldemar Lindgren, Clyde P. Ross

To the miner, as well as to the geologist, the eastern part of Cuba is a most interesting region. Here we find, in contrast to the moderate relief predominating elsewhere in the island, an imposing mountain range, the Sierra Maestra, extending east and west parallel to the coast, its precipitous front facing the blue Caribbean Sea. In a geological sense this range is largely an unknown land, the only well-explored region being that in the vicinity of Santiago. The range also contains the most important mineral deposits of the island. They comprise, first, a series of iron deposits yielding a partly hematitized magnetite with low content of phosphorus; second, a remarkable copper-bearing vein at El Cobre; and third, various manganese deposits. Probably more deposits will be found, for the larger and western part of the range is as yet little explored and its slopes are covered by a thick tropical jungle. The following notes are based on a short visit by the senior author in January and February of 1914 to the mines at Daiquiri, El Cobre, and Mayari. For many courtesies and great assistance he is deeply obliged to Charles F. Rand, President of the Spanish-American Iron CO.; to George W. Pfeiffer, General Manager, and to the several members of his staff. Geological Features of the Sierra Maestra For our knowledge of the geology of the Sierra Maestra we are indebted to reconnaissance work by Fernandez de Castro, R. T. Hill, Mr. C. Hayes, T. W. Vaughan, and A. C. Spencer. The summary by the latter three geologists furnishes the best guide to the region.' The range is undoubtedly outlined by a great east-west dislocation. Its southern slope drops abruptly to the sea, while on the north side a much gentler declivity leads down to the rolling plateau of Tertiary limestone which occupies much of the adjacent part of the island. Viewed

Jan 1, 1916

By Brent A. Elliott, J. Richard Kyle

Texas is a major producer of industrial mineral resources required by the state’s ever-growing population that now exceeds 28 million. Texas typically ranks in the top three states for the value of non-fuel mineral production with a total value of $5.2 billion in 2017, accounting for 6.9% of the total US mineral value. Almost 90% of current Texas industrial mineral value comes from the production of cement, crushed stone, industrial sand, and construction sand and gravel. Construction material consumption is focused in the 25 metropolitan areas of the state with populations of > 100,000 residents. Industrial mineral consumption is dominated by the four most populous regions of the state—Houston, Dallas-Fort Worth, San Antonio-New Braunfels, and Austin-Round Rock—with an aggregate population of more than 18 million. More than 11,000 employees work in Texas mining and processing operations. Texas produces more crushed stone than any other state from more than 200 quarries; a similar number of operations produce sand and gravel. Specialty industrial sand production for use as proppants in hydraulic fracturing for enhanced petroleum production serves as an excellent example of how developments in one industry sector can markedly affect another industry; the production of industrial sand in Texas has markedly increased over the past decade, reaching $1.3 billion in 2014. With Texas’ population projected to reach 50 million by 2050, continuing in-state development and production of industrial minerals will be required to supply its residential, commercial, and industrial users. Favorable geology and economic factors provide opportunities for identification and development of new industrial mineral production sites.

By Louise Barton Freeman, Coleman D. Hunter

The total production of oil in Kentucky during the year 1943 reached 7,010,776 bbl., which is more than at any time since 1930. Of this total, 5,287,659 bbl. was produced from the counties west of the Cincinnati arch, 692,359 bbl. from the 18 new pools opened during the year, and 3,260,765 from the Smith Mills pool, which was discovered in August of 1942. This is an important increase in western Kentucky in spite of the low price of crude, and demonstrates effectively the desire of the industry to cooperate in meeting the increased demands made by the war. Western Kentucky Two deep tests were drilled in the Kentucky portion of the Mississippi Embayment this year. Both were drilled to test the St. Peter. One well, drilled in Marshall County by the Adams Oil and Gas Co., did not encounter any St. Peter sandstone but drilled 650 ft. of formation below the position of the St. Peter and above the true Knox dolomite. The other well, in Ballard County, was reported to have tested the St. Peter and to have been temporarily abandoned at 3069 ft. At this depth the well probably was stopped in about the same formation as the Marshall County well. No accurate information is available on the Ballard County well. Several new producing areas were added to the list of fields in the western Kentucky coal basin, in Daviess, Henderson, McLean, Ohio, Union and Webster Counties. The Smith Mills pool was enlarged and production was found in the McClosky (Ste. Genevieve) in addition to the Cypress sandstone from which much of the earlier production had been obtained. There was some interest during the year in testing the Devonian and Silurian formations in the area south and east of the western Kentucky coal basin. In the fall of 1943, a 15 to 20-bbl. well was drilled in Allen County and two more wells are now being drilled. The production was obtained from within a few feet of the base of the Chattanooga black shale, probably in the upper Silurian. One well in Simpson County was drilled completely through the Silurian section before it was abandoned. Several wells were drilled in Logan, Todd and Christian Counties to test the Devonian where it is thinned by removal of the upper formations before deposition of the Chattanooga shale. None of these wells was successful but several other locations are now being tested. The Silurian thins in like manner on the eastern flank of the coal basin as the crest of the Cincinnati arch is approached, and it is along this thinning edge that such fields as the LeGrande, Logsdon Valley, Magnolia, Bowling Green and the Barren County pools were developed. A number of wells were drilled around these old pools in an effort to extend them, some of which were successful. The wells listed this year in Larue, Hardin, Barren, Hart and Warren Counties were drilled in the search for other such fields.

Jan 1, 1944

By Louise Barton Freeman, Coleman D. Hunter

The total production of oil in Kentucky during the year 1943 reached 7,010,776 bbl., which is more than at any time since 1930. Of this total, 5,287,659 bbl. was produced from the counties west of the Cincinnati arch, 692,359 bbl. from the 18 new pools opened during the year, and 3,260,765 from the Smith Mills pool, which was discovered in August of 1942. This is an important increase in western Kentucky in spite of the low price of crude, and demonstrates effectively the desire of the industry to cooperate in meeting the increased demands made by the war. Western Kentucky Two deep tests were drilled in the Kentucky portion of the Mississippi Embayment this year. Both were drilled to test the St. Peter. One well, drilled in Marshall County by the Adams Oil and Gas Co., did not encounter any St. Peter sandstone but drilled 650 ft. of formation below the position of the St. Peter and above the true Knox dolomite. The other well, in Ballard County, was reported to have tested the St. Peter and to have been temporarily abandoned at 3069 ft. At this depth the well probably was stopped in about the same formation as the Marshall County well. No accurate information is available on the Ballard County well. Several new producing areas were added to the list of fields in the western Kentucky coal basin, in Daviess, Henderson, McLean, Ohio, Union and Webster Counties. The Smith Mills pool was enlarged and production was found in the McClosky (Ste. Genevieve) in addition to the Cypress sandstone from which much of the earlier production had been obtained. There was some interest during the year in testing the Devonian and Silurian formations in the area south and east of the western Kentucky coal basin. In the fall of 1943, a 15 to 20-bbl. well was drilled in Allen County and two more wells are now being drilled. The production was obtained from within a few feet of the base of the Chattanooga black shale, probably in the upper Silurian. One well in Simpson County was drilled completely through the Silurian section before it was abandoned. Several wells were drilled in Logan, Todd and Christian Counties to test the Devonian where it is thinned by removal of the upper formations before deposition of the Chattanooga shale. None of these wells was successful but several other locations are now being tested. The Silurian thins in like manner on the eastern flank of the coal basin as the crest of the Cincinnati arch is approached, and it is along this thinning edge that such fields as the LeGrande, Logsdon Valley, Magnolia, Bowling Green and the Barren County pools were developed. A number of wells were drilled around these old pools in an effort to extend them, some of which were successful. The wells listed this year in Larue, Hardin, Barren, Hart and Warren Counties were drilled in the search for other such fields.

Jan 1, 1944

By C. F. Jackson

THE work of, the Mining Methods Committee is now well under way. Following discussions previous to and during the February meeting, an Outline for Papers on Mining Methods was prepared, and over a thousand copies have now been distributed to committee men, to section secretaries and to members who have indicated any interest in the subject. The objective of the committee is to prepare a symposium on mining methods which will be of real practical value to the operator and engineer in the solution of every-day mining problems. It is planned to cover the entire field of mining in such a way that the different branches of mining, such as coal and ore (iron, copper, lead, zinc and precious metal) can benefit from the experience of the others at points where they have problems in common.. It is realized fully that each of these branches of mining possesses its own peculiar problems, but at the same time, there are prob-lems in connection with each, where the experience in others should be of value. The committee proposes to proceed along the following lines: 1. To present a general classification of mining methods, showing their inter-relationship, and at the same time .provide a common language for the discussion of mining methods and a nomenclature that will have the same meaning wherever used. A com-plete set of illustrations will accompany the classi-fication to make clear the terminology adopted and to show graphically the inter-relationship of methods. 2. To show the relationship between the physical characteristic of the deposit, the economic consider-ations and the. mining method., It is not proposed to treat this subject as a mere academic problem, but to secure reports from every mining company of impor-tance in this country, which will show what methods or modifications and combinations of methods have actually been applied and the physical conditions and economic considerations which have led to the adoption of these methods in each case. The Mining Methods Committee has drawn up an Outline for Papers on Mining Methods to be distributed among mining engineers and operators, giving in detail the information desired. This outline is the result of several months of careful thought and is a composite of the suggestions of many engineers and mining company officials from all parts of the United States.

Jan 7, 1922

By Lawrence D. Hoy, Armand Savoie, Pierre Trudel, Ghislaln Tourigny, Robert Crépeau, Lao Kheang

"Recent fluid inclusion and stable isotopic studies in the Bousquet mining district have identified spatial and temporal trends in mineralization temperatures and isotopic compositions of vein forming fluids. These studies indicate that mineralizing temperatures were lower during sterile vein formation (T=200-300°C) than during auriferous vein formation (T = 300-400°C), and that 8 80 values of minerals in sterile veins are lower by 1-3 %o than in associated auriferous veins. In addition to these small differences in 8 80 within individual mineralized zones, a trend of increasing 8 80 values of vein minerals is identified from west to east across the district, with 8 80 of vein minerals increasing by4-6%o. Quantitative evaluation of potential causes of the observed oxygen isotopic shifts suggests that the best explanation for these trends is the derivation of the mineralizing fluids from an isotopically inhomogeneous terrain in which the fluid isotopic compositions are controlled by the isotopic compositions of the host lithologies due to high rock/water ratios in these source terrains. This inhomogeneous source terrain is interpreted as consisting of the Blake River Group volcanics (low 8 80 component) and the adjoining Kewagama and Cadillac Group sediments (high 8 80 component).The genesis of the hydrothermal fluids is attributed to crustal heating during metamorphism, with the fluids representing metamorphic dewatering products and/or fluids incorporated during deposition and burial of the host lithologies. Ductile deformation of the fluid source regions impeded fluid migration during metamorphism; the ultimate release of the mineralizing fluids is attributed to the penetration to depth of vertical structures (fault and shear zones) during brittle deformation of the crust under waning metamorphic conditions. Release of fluids caused by this puncturing of the closed hydrologic source regime produced a localized zone of lowered pressure, drawing fluids from adjacent lithologies toward the fault zones, feeding further hydrothermal fluid upwelling. Au mineralization resulted from chemical processes related to cooling of the hydrothermal fluids and/or interaction with lithologies encountered during fluid migration; the level of crust at which Au deposition occurred likely migrated upward with the thermal anomaly caused by hydrothermal fluid upwelling, eventually reaching the level of current exploitation. Cessation of fluid flow along the vertical structures is attributed to inadequate recharge of the hydrothermal systems as fluid contents were depleted in the lithologies proximal to the vertical structures and/or sealing of the structures by mineral deposition."

Jan 1, 1990

By F. A. Skirvin

Purification techniques were investigated for removing low-level metallic impurities from tungsten hexachloride. These techniques included distillation) fused-salt scrubbing) zone refining) and adsorption. Fractional distillation of tungsten hexachloride was found to be an effective purification method. The impurity levels of molybdenum) iron) nickel) copper) magnesium) and manganese were reduced to provide a tungsten halide sample which contained a total of less than 10 ppm detectable metallic impurities. Purification by fused-salt scrubbing of tungsten hexachloride in a lithium chloride-potassium chloride eutectic produced a hexachloride product which was of approximately the same quality as that obtained by distillation. Zone refining and adsorption did not appear to be as effective as distillation or fused-salt scrubbing.

Jan 1, 1967

By Osmar de Sousa Santos

NiTi shape memory alloys (SMA) have been widely used as construction materials due to their shape memory and superelastic properties. Usually the application of the NiTi alloy is in the wire form, which is ideal shape to make springs, orthodontic arc-wire and endodontic files. Since our research group (ITASMART) started producing NiTi wires, it was noticed that NiTi SMA produced by Vacuum Induction Melting (VIM) presents carbon contamination, which is due to the melting process. Therefore, alloys rich in carbon remove titanium from matrix, forming precipitates of TiC (titanium carbide). Also, Ti2Ni precipitation removes titanium from the matrix and these two precipitates TiC and Ti2Ni can produce internal volumetric defect in the wire drawing process. Seeing the importance of NiTi wires as base of many applications, this work studies the formation of volumetric defects caused by precipitates in the wire drawing process of a NiTi wire drawn down to 0,39 mm in diameter.

Aug 8, 2018

By J. F. Barkley

The work covered in this report was done to meet the requests from many Government agencies for information on alleviating sludge difficulties in No. 6 (Bunker C) fuel-oil storage tanks. Accumulated sludge at times caused serious loss in tank capacities; pumps became overloaded or lost suction; strainers often required very frequent cleaning; fuel-oil heaters in some instances became fouled and inefficient; and gobs of sludge that passed the strainers interfered with good combustion. The requests also included questions regarding the usefulness in general of oil "additives" for preventing sludge and the relative merits of the many trade-named additives being marketed. Realizing that preventing such difficulties would result in substantial savings to the Government, an investigation was begun with the limited funds avail-able. Although various claims are made for No. 6 fuel-oil additives other than preventing sludge, only an investigation as regards the storage tank-sludge problem has been possible.

Jan 1, 1955

By Magda Moreira Pinto

Durante a fabricação do aço as grandes siderúrgicas possuem usinas térmicas integradas aos seus processos industriais. Uma operação bastante comum na indústria siderúrgica é a geração de vapor, normalmente utilizado para a produção de trabalho mecânico em turbinas (vapor superaquecido) ou em processos de aquecimento, nos quais se emprega o vapor saturado. Estes vapores de processos também podem ser utilizados na geração de energia elétrica. Para isto, foi importante assegurar a qualidade da água e do vapor de baixa pressão (VBP) enviado para Termelétrica. Foi com este intuito que a TKCSA se preocupou em padronizar o (VBP) gerado na Caldeira Auxiliar da área de Utilidades e Caldeiras da Aciaria. O desafio era transformar o (VBP) na mesma qualidade do vapor produzido nas caldeiras recuperadoras de calor (HRSG). O procedimento adotado foi á modificação no tratamento químico, a instalação de uma monitoração química contínua e eficiente para assegurar os parâmetros químicos dentro da especificação técnica recomendada pelo EPRI - Electric Power Research Institute, Inc. Com este tratamento foi controlada as dosagens químicas, a operação da caldeira e a geração dos efluentes líquidos para o tratamento químico ambiental. Contudo foi possível tornar um mecanismo dinâmico e econômico para a empresa viabilizando a utilização do vapor na termelétrica.

Jul 31, 2018

By Corliss R. Kinney

SINCE the first atomic bomb exploded over Japan, a great deal of speculation has been published about the use of atomic energy instead of coal for the production of power. Atomic energy, in time, may displace coal for this purpose, but atomic energy will not displace coal in supplying chemical raw materials to the rapidly expanding carbon-chemicals market. Modern civilization demands large quantities of carbon compounds and the logical source of many of these is coal. Consequently, many progressive operators are considering the possibilities of the utilization of coal as a chemical raw material as never before. Furthermore, the demand for clean, smokeless, and ashless fuels will continue to increase and the only way to handle coal under those conditions is to take it apart, just as crude petroleum is taken apart. One can readily imagine where the petroleum industry would be now if it had insisted on selling customers only crude oil, perhaps emulsified with a little salt water to correspond to the moisture and mineral matter in raw coal. The time seems to be coming at an accelerated pace when mine operators will find that competing for a highly selective fuel market by producing a larger tonnage at smaller cost will be less profitable than to increase the value of a smaller tonnage many fold by producing something more valuable to industry and civilization than raw coal. For example, about 750,000 tons of carbon black selling for $50 to $60 per ton was produced in the United States in 1945. This tonnage is insignificant compared with the total production of coal in the United States, but a very tidy tonnage, together with the coal necessary to operate the process, for any mine operator fortunate enough to obtain a method of producing a better carbon black from coal. From the point of view of tonnage, the manufacture of coke of various kinds and its by-products is at present the most important source of carbon chemicals from coal. Nearly 20 per cent of the coal mined in this country is used for this purpose. A large proportion of the coke is used for the production of iron and steel, but even in this operation a considerable part of the coke is used for a chemical purpose; that is, the reduction of the ore to metallic iron. In addition, large quantities of coke are used in manufacturing many important products that find their way into the market. POSSIBILITIES OF ACETYLENE One of the important chemicals manufactured from coke is calcium carbide, from which many products are made. One of these is acetylene. This hydrocarbon can also be manufactured from natural gas or from waste oil-refinery gas and' these industries will probably offer competition for the manufacture of acetylene. Coke-oven gas can be used for making acetylene and should receive consideration

Jan 1, 1946

This paper discusses the potential role of underground space and tunnelling in urban planning in Australia. The paper gives examples of the infrastructure and commercial applications of underground space which have been effectively used overseas but have been slow to be considered as a part of urban planning in Australia. In particular, the paper looks at underground quarrying and underground commercial development and their potential use in the urban environment. Existing sites and potential sites for quarrying and/or commercial use have been classified using a system developed by the author. Underground quarrying may provide some solutions for planning problems involving sand and aggregate supplies, waste disposal and other uses. Commercial development involving underground excavation may be accepted if the cost of underground commercial development can be shown to be equivalent to the cost of above ground development. The paper concludes that one role of the underground construction industry is to promote tunnelling and underground space amongst architects, town planners and planning decision-makers. The Australian Underground Construction and Tunnelling Association (AUCTA) and the Australian Society for Trenchless Technology (ASTT) should be instrumental in actively promoting the use of underground space in society.

Jan 1, 1999

By M. T. Ityokumbul

Concentrate flowrates have been measured for the flotation of -100 mesh Lower Kittaning coal in a computer controlled 0.076 m x 3.5 m pilot flotation column. The variables studied were recovery zone height), air flow rate, and solid feed concentration. The size distribution of concentrate and tailings samples were determined. The results obtained show that the concentrate flow rate was independent of collection zone height, but dependent on the gas flow rate, solid loading and particle size. New correlations for column carrying capacity and yield are provided as a function of these fundamental operational parameters.

Jan 1, 1997

By J. C. Gibson, C. H. Stockwell

"The San Antonio gold mine is at Bissett, Manitoba, on the north shore of Rice lake, 100 miles northeast of Winnipeg. Gold was discovered on the property in 1911, but intensive exploration was not undertaken until 1926. Milling commenced on May 1st, 1932. Total amount of ore milled from that time until the end of 1946 was 1,766,670 tons, having a value of $18,378,317.GENERAL GEOLOGYThe rocks in the vicinity of the mine are Precambrian and include three groups, namely, the Rice Lake series of volcanic and sedimentary rocks, basic and acidic intrusions, and a younger formation of sediments known as the San Antonio formation (Fig. 1). The lower part of the Rice Lake series, consisting of flows of rhyolite, trachyte, and andesite with interstratified beds of agglomerate, occupies an area extending southward from Rice lake. The lake itself and the country to both east and west of its northern end is underlain by the next succeeding beds of the series, which are chiefly tuffs, arkose, and conglomerate, but include a thin band of basalt. Northward from the lake, these are succeeded by the upper beds of the series, first a thin band of basalt and, overlying this, porphyritic andesite flows interlayered with beds of volcanic breccia or agglomerate.The Rice Lake series has been invaded on the east side of the lake by a body of basic rock ranging in composition from gabbro to diorite and quartz diorite, now much altered. This is cut by younger sills and dykes of basic rock, probably diabase, the original texture of which is largely destroyed by alteration. Numerous dykes of feldspar porphyry, quartzfeldspar porphyry, and a few of a rhyolite-like rock, occur south of the lake, but are uncommon to the north. They cut the diabase and older rocks.Extending westward from Rice lake and lying with marked angular unconformity against all of these rocks is the San Antonio formation, consisting of cross-bedded, arkosic quartzite."

Jan 1, 1954