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By E. Zucker

In this paper, as in the 1960 CIM paper of the same name, s1gmf1cant new developments in electrical-mechanical mining equipment are briefly described. These include static thyristor-supplied D.C. drives for mine hoists, load-haul-dump systems, process controls with small and medium-size computers, and several other new items of equipment and Concepts. All the new hardware descriptions are given in the context of over-all process integration. This means the actual mechanical linking together of two or more processes and the preliminary step in the development of production-line mining.

Jan 1, 1969

Overview n Why we audited the IRS n How we did it n What we discovered n What we learned n Where we are going next The unbroken chain of safety The Internal Responsibility System (IRS) The network of roles and relationships in a workplace, through which everyone works with mutual commitment to reduce or eliminate hazards.

May 1, 2003

By J. Oliver, B. Wilson, 10

"Red Dog is one of the world’s largest zinc producing mines and a significant producer of lead and silver. While some of the operational challenges relate to the mine’s location in a remote part of Alaska, there are also challenges in the mineral separation process. Recent processing upgrades have included the installation of two M5000 IsaMills to improve the zinc regrind circuit and of one Jameson Cell to improve the pre-flotation circuit. Relatively fine grinding is required to achieve efficient mineral separation at Red Dog, but while fine grinding aids in the production of high grade concentrates, it also creates challenges in the efficient recovery of fine minerals. Over half of the lead lost to the lead circuit tailings, as well as almost half of the zinc lost to the final tailings, is in the finer size fractions (<10 µm). The high pulp density experienced in the pre-flotation and lead rougher circuits also causes significant entrainment loss of lead and zinc to the pre-flotation concentrate and of zinc to the lead concentrate. To help improve fine mineral recovery, Red Dog has recently plant tested and installed magnetic conditioning technology in the flotation circuits. The equipment aggregates fine paramagnetic sulphides and selectively increases their flotation recovery. This paper outlines the testing and positive results at Red Dog.INTRODUCTIONRed Dog is the largest zinc mine in North America and represents approximately 29% of North American zinc concentrate production. The mine is located in northwest Alaska, approximately 100 miles north of the Arctic Circle and 50 miles inland from the Chukchi Sea. The remote location makes the mine accessible only by air or seasonally by ocean-going barges. Red Dog is a partnership between NANA Regional Corporation Inc, the land owner and Teck Alaska Incorporated, the operator of the mine. Red Dog Ore and Mineralogy The Red Dog deposit is a rich sedimentary exhalative (sedex) zinc-lead-silver deposit. The main minerals present in order of abundance are: quartz, sphalerite, pyrite, barite and galena. Production began in 1989 with mining of the Main deposit. Between 1989 and 2012, approximately 55.6 million tonnes of ore with an average grade of 20.5% Zn, 5.6% Pb, and 97 g/t Ag was mined from the Main deposit. Subsequent to the development of the Main pit reserve, two additional open pit deposits were discovered: Aqqaluk and Qanaiyaq. The first blast in Aqqaluk occurred on June 4, 2010. As of December 31, 2014, the Aqqaluk deposit reserve is an estimated 45.7 million tonnes of ore with an average grade of 15.1% Zn, 3.9% Pb and 71 g/t Ag."

Jan 1, 2016

By J R. O Walli

Large production shafts can be successfully sunk through the ubiquitous Blairmore formation of southern Saskatchewan by employing the freezing process and by the installation of a cast iron tubbing lining. Although the freezing technique for shaft sinking and the use of cast iron tubbing to preserve the shaft are new to the North American continent, these procedures have been employed in Europe for the past eighty years. More than 200 shafts, covering a wide variety of ground conditions, have been sunk by the freezing process, and most of these have been lined with cast iron tubbing. The No. 1 shaft of International Minerals and Chemical Corporation, near Esterhazy, Saskatchewan, comprises the first major example in Canada of the employment of European methods to overcome extremely difficult ground conditions. The Blairmore formation was solidified by the deep freezing process, employing a lithium chloride solution as the refrigerant, with input temperatures ranging to -55°F

Jan 1, 1964

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac&apos;s harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By L. Long

Stirred milling of nickel laterites offers possibilities for improving liberation and selective size reduction of soft nickel-bearing minerals in laterites. Batch grinding tests were performed in a Netzsch LME4 stirred mill on siliceous goethitic (SG), goethitic (G), and saprolitic (SAP) nickel laterite samples (- 2000 ?m particle size) to evaluate the effect of stirrer speed, solid content, water salinity and grinding time. A fine mineral product (-38 µm) was used to evaluate the effect of selective grinding and Ni upgrade. The optimum grinding time for the highest Ni upgrade was 0.25 min, 0.1 min and 0.1 min for the SG, G, and SAP nickel laterite, respectively. A new feed (38-2000 µm) for each nickel laterite sample was prepared for batch grinding tests under the optimum grinding conditions. Upon grinding the 38-2000 µm feed, the - 38 µm product confirmed the effect of selective grinding and nickel upgrade. Size classification followed by stirred milling is a suggested process for Ni upgrade. The best Ni upgrade result was achieved on the SG nickel laterite among the three samples. The Ni grade increased from 0.85% to 1.37%, with 27.8% Ni recovery. Bottle roll leach tests showed that for SG and SAP samples selective grinding had no dramatic effect on Ni extraction due to the slow leach rate of hard mineral particles. Stirred milling of G sample increased the surface area of goethite, resulting in higher Ni extraction. Gravity concentration through a Knelson Concentrator was not effective in the further treatment of the stirred milling products either due to the poor operating conditions or due to the mineralogy characteristics of the feed samples. The energy requirement in the stirred milling was investigated. The first pass of the signature plots study is critical for the purpose of selective grinding, because the best result on selective grinding is achieved in the early stage of the grinding process.

Aug 1, 2013

By J. Oyunaa, P. Munkhbaatar, A. Sarnai

"The molybdenum mining process used at Mongolia Erdenet Company is a selective flotation of molybdenite from the copper porphyry ores in which the extraction of molybdenum comes as a byproduct of the ongoing copper production.The mineralogical composition of molybdenum concentrate is 99.4% molybdenite (MoS2), 0.09% molybdenum oxide (MoO3), 0.52% powellite (CaMoO4) and wulfenite (PbMoO4) and content 47.76– 47.92% molybdenum, 1.5–2.67% copper, 0.04% renium.From compared solvents sodium and carbonate and ammonia are like extracted molybdenum than hydrochloric acid, which contained 96.23–97.72 p.c. of its total amount. Hence to take into consideration abundance, cheap and suitable for analysis and processing the molybdenum concentrate ammonia is choosing as a basic solvent. By direct evaporation of ammonia extract solution, we obtained ammonium ortomolybdate, which contains 73.47% MoO3. INTRODUCTIONMolybdenum occurs in the earth’s crust in an abundance of about 10–14%, mainly as molybdenite, MoS2. Small quantities are also associated with other metals having similar chemical properties. Thus wulfenite (PbMoO4) is found in oxidized parts of sulfidic lead deposits in many regions of the world; powellite [Ca(Mo,W)O4] is a calcium molybdate usually formed from the modification of molybdenite in deposits containing tungsten as scheelite (CaWO4) and tungsten substitutes for molybdenum up to about 10%. Ferrimolybdite (Fe2Mo3O12·8H2O) is the product of oxidation of molybdenite in the presence of iron (III) compounds. Molybdenite is the primary source of molybdenum. Should demand for molybdenum rise so that additional sources become necessary, wulfenite, powellite, and ferrimolybdite may become commercially significant. Molybdenum ore is mined by underground and open-pit methods. A typical primary molybdenum ore body contains 0.05–0.25% Mo, and secondary ore bodies (copper porphyry ores) average 0.3–1.6% Cu and 0.01–0.05% Mo. Flotation remains the preferred and almost exclusive method of upgrading the molybdenite mineral to an industrial-grade molybdenite concentrate containing 90–95% MoS2, the balance being gangue (Habashi, 1997)."

Jan 1, 2016

By Pierre Bernard

Contents of the presentation ? Overview of Brunswick 12 Mine ? Brief description of the mine geology ? Summary of the current Mineral Reserves and Additional Mineral Resources ? Review of the ongoing mining remnants evaluation process, particularly emphasizing the integrated work between the mine geologists, the mine engineers and the metallurgists ? Challenges and opportunities to extend the mine life

Apr 1, 2005

By J. M. Paxton, R. L. Roscoe, G. A. McCreary, W. W. Muir, T. J. Drown, D. A. Barr, T. W. Law

"This paper reviews the complete cycle of a small mining operation in a remote section of northern British Columbia, including discovery, exploration, development and production. The discovery of high-grade epithermal gold-silver mineralization occurred in 1969 following a regional geochemical reconnaissance program designed to search for porphyry copper mineralization in the Cassiar-Omineca Mountains. Exploration and development from 1971 to 1979 included geological, geochemical and geophysical surveys; trenching, almost 30 000 feet of surface and underground drilling in about 100 holes and cross-cutting, drifting and raising on the principal goldsilver- bearing vein. This led to the delineation of 100000 tons at an estimated grade of0.9 oz gold per ton and 18 oz silver per [on to an average depth of 120 feet below surface. of a 100-ton per day mining operation employing about 50 personnel with all supporting infrastructure transported to the site by a Hercules aircraft. The operation was subsequently supported by its own Twin Otter aircraft with periodic Hercules campaigns supplying major items including fuel.The mining operation included both open-pit and cut-and-fill methods. The milling operation employed conventional cyanide leach process with cyanide destruction initially by alkali chlorination and subsequently by the Inco SOl /Air process.The fly-in operation, initially structured on a 21-day-in and 7-day-out basis was modified to al-t-day-in and Z-day-out basis with no loss in efficiency and with a significant increase in employee satisfaction. The operation, which earned the B.C. Small Mines Safety A ward in two consecutive years in its Ll-month operating history, emphasized safety and process hazard awareness. Wildlife studies in the environmentally sensitive mine area also showed that industry and wildlife can coexist in harmony.Most importantly, the paper compares the feasibility assumptions with actual operating experience."

Jan 1, 1986

By S. Bhattacharjee

"Rock failure process is generally recorded or measured using conventional sensors like strain gauges, seismic, micro-seismic, acoustic, electromagnetic and other techniques. The above sensors are either to be pasted on the surface of the rock sample or placed very near to it to capture the response of the sample with the increment of load. This requires precise tools to cut or polish the locations where sensors are to be placed. Moreover, deformation or acoustic or micro-seismic activities are recorded only at the locations where sensors are pasted.Recent development in Digital Image Correlation (DIC) technique has shown promise to measure deformation / strain at every location of the surface of a sample. In DIC, two images (reference and deformed) are taken within a small time interval of the same object are compared to estimate the change in reflectance as a function of displacement, velocity or rate of strain at each pixel while the object is undergoing through a loading process. In this study, extended digital image correlation (X-DIC) technique has been implemented using 4-noded quadrilateral elements with a discontinuity surface in the deformed image. The continuous and enriched displacements are estimated at each node.The X-DIC method is verified using numerically generated images. The study has been further extended to evaluate the performance of X-DIC method on deformation analysis of experimental samples under uni-axial loading condition. The results of this study show that X-DIC method is an effective tool for determination of displacements of the entire surface of a rock sample having a discrete crack or discontinuity in a non-contact manner. This method demonstrates the applicability to investigate rock failure mechanism for the entire sample in a laboratory set up as well as monitoring of pillar failure mechanism in underground mines."

Jan 1, 2015

By A. A. el-Geassy, A. A. el-Tawil, Hesham M. Ahmed, Bo Bjorkman

The Iron and steel industry is one of the most intensive energy consuming processes. The majority of iron making processes is now directed towards the uses of fossil-based energy sources like coke, coal and oil. Recently, emphasis has been paid to replace part of fossil- based energy sources with renewable biomass-derived reducing agents. In the present work, the possibility of the effective use of woody biomass in carbon-iron oxide composites was investigated. Wood powder was carbonized in N2 atmosphere at 300 up to 450oC. The carbon content in the produced bio-char increased with temperature. The porosity of the char arises from maintaining the cellular structure inherent in wood biomass increases with temperature. The reduction behavior of four iron oxide-bio char composites having different fixed carbon content were carried out non-isothermally up to 1200oC in Ar atmosphere using thermogravimetric anlyser (TGA). Quadruple mass spectroscopy (QMS) was also adopted to measure the CO, CO2 concentrations in the off gases resulted during reduction process. The effect of volatile matter on the reduction of iron oxide was intensively studied. The different phases developed in the reduced product were identified by X-ray diffraction (XRD). The reduction of composites was found to proceed in a stepwise manner (Fe2O3?Fe3O4?FexO?Fe).

Jan 1, 2015

By Angus D. Campbell

Introduction In the Twentieth Annual Report of the Mcintyre Porcupine Mines, Limited, for the year ending March 31st, 1932, the General Manager, Mr. R. J. Ennis, said: "During the period under review, the plans outlined in last year&apos;s report have been completed, and all operations have been centralized in the new plant adjacent to No. 11 shaft. The new mill went into operation on May 27th and attained its rated capacity of 2,000 tons per day on November 15th. The new shops, warehouse, change-house, and general offices were occupied on December 1st, consummating the change from the old to the new plant ... "Silicosis is now definitely recognized as an industrial disease, and progresses rapidly when associated with tuberculosis. In an effort to combat its prevalence and progress, the new change-house was designed to build up the men&apos;s resistance to this and other forms of disease. It provides for a complete change from underground to street clothing, with a shower bath and solarium treatment in the interval. &apos;Unfortunately, in almost every goldmine, a very small percentage of the work-men are not adverse to taking some of the high-grade ore for their own purpose. This, in turn, tends to cast suspicion upon the honourable as well as the dishonorable employees. The new change-house routine discourages this practice and eliminates unjust suspicion, to the satisfaction of all concerned with the Company&apos;s operations".

Jan 1, 1933

By J. J. McDougall

Until quite recently, the coal in the Cape Breton field was won from comparatively thick seams with light cover, and from submarine areas, and the system of mining naturally followed was pillar-and-stall. This sytem permitted of cheap extraction, and enabled production from localities where other methods could not be employed to good advantage. Thus the pillar-and-stall system, applied to conditions as stated, justified its adoption. Our working seams today, however, are practically all under heavy cover, or are moving in that direction, and with this gradual increase in cover came the increased cost of roadway maintenance. At Princess colliery, the system of pillar-and-stall was followed until roof and bottom conditions became such that further operations were unprofitable, and the longwall method was then adopted as an economic necessity. This fact should be borne in mind when operating costs of both systems are being compared. The longwall method is not held as a cure for all difficulties of heavy cover, but through it these difficulties can be overcome with less expense than by pillar-and-stall. The longwall system of mining, strictly speaking, is one by which a seam of coal is totally extracted in one operation. There are, however, many modifications of longwall, and in some cases it is difficult to determine whether certain practices should be classed as longwall or pillar-and-stall, or a combination of both.

Jan 1, 1928

By B. M. Monaghan

"The developments of the 1950s and 1960s have seen Canada become an international source of iron ore, trading in all geographical areas and hemispheres. Canada's production will significantly increase in the next decade. However, although the outlook is bright, iron ore producers cannot be complacent. Instead, we must weigh the factors that have brought about the development of the Canadian iron ore industry and examine the probable changes for the next decade that will affect its growth.Looking ahead in the 1970s, competition will be severe. Pressure on prices will continue as new sources of supply bid for long-term contracts and as steel producers continue to develop mines around the world. Rising costs will make these pressures more severe. We must balance the growth of the world's steel makers with the emergence of new supplies of iron ore. The iron ore industry is now part of a new era in which demand and supply are intermeshed, and the developments around the world are acting on the Canadian iron ore industry's future."

Jan 1, 1971

By Jehan Rondot, Raymond Marleau

"Des quartzites trés pars ont été découverts au cours de la cartographie de la region du lac des Martres, étape de l'étude géologique de la region de Charlevoix.On distingue quatre groupes métasédimentaires, tons con tenant des niveaux de quartzite dans an mains deux domaines géologique différents, c'est à l'ouest, clans le do¬maine gneisso-charnockitique que se situent les quartzites du groupe des Martres. Quartzite et gneiss à, grenat et sillimanite, en banes épais, constituent la formation de La Galette. A Pest, dans un environnement gneisso-granitique, les deux groupes métasédimentaires de Saint-Siméon, et de La Malbaie comprennent, par contraste, des bancs pen épais et de compositions variées. Les niveaux de quartzite dépassent rarement 50 m d'épaisseur. L'autre groupe métasédimentaires, celui de Saint-Tite des Caps, recoupé de nombreuses intrusions charnockitiques et granitiques, ne possède que de minces niveaux de quartzite.La pureté et la grande épaisseur des quartzites de La Galette suppose une histoire complexe qui se termine par des depots continentaux de climat aride, par opposition aux depots marins des autres groupes. D'autre part, la presence de ces quartzites an sein de roches Presque anhy¬dres et de haute temperature que sont les charnockites leur confére des caractéristiques de fusion sans decrepitation.Parmi la multitude de depots de quartzite qui existe clans le monde, peu sont de qualité supérieure. Or, de par sa composition chimique, le quartzite de La Galette se compare avantageusement à ceux des meilleurs gisements des Etats-Unis, de l'Europe de l'Ouest et de l'Afrique du Sud. D'accès facile pour l'exploitation, les gisements ne sont qu'à une trentaine de milles de Baie Saint-Paul ou de La Malbaie, sur le Saint-Laurent.L'utilisation en metallurgic prévue pour le quartzite de La Galette comprend la production de silicium, de ferro¬silicium et d'autres alliages de silicium. La composition du quartzite est en outre appropriée pour la production de carbure de silicium et de silicate de sodium. Les fines peuvent être utilisées pour la fabrication du verre et comme matiere de charge"

Jan 1, 1977

By Thomas Clark

This report presents a review of the distribution and exploration potential of platinum-group elements (PGE) in Québec; it is based on published and unpublished analytical data. This qualitative evaluation of the PGE potential, whether in PGE-dominant deposits or in Ni-Cu-dominant deposits with co-product PGE, is based on interelement ratios such as Ni/Pd, Cu/Ir, Cu/Pt, and Cu/Pd. Good PGE targets, i.e., deposits associated with magmas fertile in PGE, are identified. Less favorable PGE targets, i.e., deposits associated with PGE-depleted magmas, are also mentioned. The importance of exploring for deposits similar to those at lac des Îles and East Bull Lake (Ontario) is emphasized.

May 1, 2001

By Harold L. Gibson, David H. Watkinson

"Volcanogenic massive sulphide deposits of the Noranda Camp cur throughout the Noranda Shield Volcano but are concentrated and along the margins of the Noranda Cauldron. The deposits are realized along synvolcanic faults that also accommodated subsince and controlled the location of eruptive centres. Deposits within e 3 000 m thick Mine Sequence formed during a period of active volcanism and subsidence coinciding with the onset of two cauldron subsidence cycles. The Noranda Cauldron was a restricted site of 10malously high heat flow and structural permeability that favoured e development of a high-temperature hydrothermal system. Metals may have been derived from leaching of aquifer rocks by convecting a water or directly from a shallow underlying magma chamber, now presented by the Plavrian Pluton, that was at its highest position !thin the crust during cauldron subsidence. The deposits formed rough a combination of sulphide precipitation from exhaled fluid td replacement at and below the seafloor in a manner analogous to ose on the modern seafloor.RESUMESi les dépôts de sulfures massifs volcano gènes du camp minier de ~uyn-Noranda sont présents dans les différentes parties du volcanluclier de Noranda, ils se trouvent concentres toutefois, en plus ·and nombre, sur le pourtour de la caldeira (cauldron) de Noranda. ~s dépôts sont localises le long des failles synvolcaniques qui ont cilite la subsidence et contrôle la position des centres d’éruption.~dépôts situes dans la séquence des mines (3 000 m d’épaisseur) sont formes durant un épisode d' activité volcanique et de subsiden qui coïncide avec l' amorce de deux cycles d' affaissement de la rldera (cauldron) de Noranda. Celle-ci Jut le site exclusif d’unflux : chaleur anormalement élevé et d’une perméabilité d’origine cucturale qui ont favorise le développement d’un système hydrothermal a haute température. Les métaux proviennent soit directement d’une chambre magmatique situee afaible profondeur, so it d’un lessivage des roches de l’aquifère par l’eau de mer circulant par convection. Cette chambre magmatique, représentée maintenant par le pluton de Flavrian, se trouvait à son niveau le plus élevé dans la croute au moment de l’affaissement de la caldeira (cauldron). Les dépôts se sont constitués par un mecanisme combinant remplacement et précipitation de sulfures à partir des fluides exhalatifs, au niveau ou au-dessous du plancher océanique, de la même manière que se forment de nos jours, les dépôts de sulfures massifs au fond des océans."

Jan 1, 1990

By S. N. Kalyakin, D. S. Flett, M. A. Mulagaleeva, N. V. Gudkova, S. S. Serdyuk, V. I. Kuzmin, Institute of Chemistry and Chemical Technology SB RAS, O. A. Logutenko, V. N. Kuzmina, V. G. Lomayev

"The Chuktukon niobium-rare earth elements ore deposit is located in Siberia (Russia). Weathered carbonatite crusts are the basis of the ore deposit. The deposit itself is 3.5 km in length, about 800 to 1400 m in width and up to 200–300 m in thickness. The ores are composed of iron-manganese oxides (hydrogoethite, hematite, psilomelane, pyrolusite) and contain 3–7% of rare-earth phosphates (florencite, monazite) and 0.5–1% of niobium oxide (pyrochlore). The ore is completely finely dispersed and consists of oxide particles formed of compact, dense aggregates which makes ore dressing as well as leaching of the rare and radioactive elements very difficult. Several options for processing of these ores have been considered: 1) reduction of the iron oxides to magnetite followed by beneficiation with magnetic separation to produce a rare metal concentrate; 2) processing of the rare earth elements (REE) containing minerals by direct alkaline-acid treatment; 3) processing of the ores using nitric acid leaching in an autoclave.INTRODUCTIONThe Chuktukon niobium-rare earth metal ore deposit is located in Siberia, in the Krasnoyarsk region, 110 km from the Boguchan hydroelectric power station which has recently been commissioned. This mineral raw materials is capable of providing impetus for the modernization of the Russian rare metal industry because of its qualitative and quantitative characteristics. The deposit is located in a region of promising industrial development and is a part of the territoriy where the Russian Federation’s Program “Complex Development of the Lower Angara Region” is currenly being realized. The main program directions are creation and development of industrial activities in sectors such as power, metallurgy, oil and gas, gold, rare-metals, and timber. The program will aid the development of the niobium and rare-metal resources of the Lower Angara and neighbouring regions as well as increase the national production of REE and therefore import substitution (Lapin, 1997; Lomaev & Kuzmin, 2003; Lomaev & Serdyuk, 2011; Serdyuk, Lomaev, & Kontorovich, 2000)."

Jan 1, 2016

By Yanping Xiao, Ton van Sandwijk, Gus Van Weert, Larry McHugh, Thomas Zabev

"All attempts to remove significant amounts of arsenic from enargite via neutral or reductive pyro routes have required operating temperatures between 600 and 700 º C, too high to propose an equipment development program. Operating at reduced pressures, or using hydrogen or elemental sulphur as a sweeping gas did not help to lower these temperatures. Admixing iron powder gave excellent results, but still required 700 º C. By fortuity, in recent experiments to produce tennantite from an enargite mineral sample, it was observed that enargite was completely converted to bornite, chalcopyrite with minor residual tennantite within an hour at 400-450 ºC. This is believed to be due to the presence of pyrite in the mineral sample treated. All earlier decomposition work appears to have been done on predominantly enargite (i.e. low pyrite) samples, or at high operating temperatures, ignoring possible reactions at lower temperature. The decomposition of enargite into iron substituted tennantite plus some bornite under evolution of liquid elemental sulphur, followed by further decomposition of this tennantite into bornite and volatile arsenic sulphides, appears experimentally feasible at these low temperatures and mimics described ore genesis pathways at > 250 ºC in saline solutions. We suggest two pathways to describe the observed experimental results:20 Cu3AsS4 + 12 FeS2 ???5 Cu10Fe2As4S13 + 2 Cu5FeS4 + 31 S(l)31 S(l) ???31 S(g) (evaporation)5 Cu10Fe2As4S13 ???10 Cu5FeS4 + 10 AsS(g) + 5 As2S3(g)"

Jan 1, 2014

By R. S. Douglas

Introduction During the past few years, a number of changes in the mine operations at Copper Mountain have taken place. The modernization and mechanization were necessitated and given impetus by wartime and other conditions, which were: (1) The urgent need for copper for wartime purposes. (2) The scarcity of skilled labour for underground work. (3) The increase in labour and supplies cost. (4) The necessity of finding ways and means of increasing the output per man-shift, because of the scarcity of skilled labour and the rising cost of labour. (5) The desire to increase safety measures, reduce the silicosis hazard, and aid mine ventilation. (6) The desire to improve the general working conditions in the mine for all workmen. (7) The desire to reduce the amount of dilution in the ore stream by a more selective yet highly productive method of mining. To this end, mining with diamond drills, and transferring broken ore with slusher hoists, appeared to be the answer to the problem. After considerable discussion and estimation of costs for comparison with those of the operation as carried on at that time, the proposed methods were tried out and, in practice, gave very gratifying results. Reference at this point is made to the paper written by C. H. Brehaut, W. N. Taylor, H. A. Shannon, and R. S. Douglas, which was published in the September, 1945, issue of Mining Technology, by the American Institute of Mining and Metallurgical Engineers, Inc., and subsequently in commercial mining journals. Since that time some improvements have been made in undercutting an orebody - the first through experiment and practice, the second through making use of the earth&apos;s barodynamic or gravitational forces. It is the purpose of this paper to describe and discuss these later developments.

Jan 1, 1947