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By William D. Macdonald

The Upper Devonian Kettle Point black shale of southern Ontario is poorly exposed. Structural maps pre-pared from the data of numerous wells show that the upper surface of the formation has low regular relief, and that the lower surface reflects domes in the Middle Devonian and also local subsidence of the Devonian rocks due to solution of salt in the Silurian Salina Formation. The appearance of minor amounts. of marcasite, pyrite, and calcite, m that order, as interpreted from the evidence of concretions from the type locality at Kettle Point is thought to have been influenced by a rise m the pH within anaerobic sediments preceding compaction.

Jan 1, 1960

The Challenges in Mining _Large expensive assets that are not being utilised as well as they should _?Silo? operations plan, schedule and execute in isolation?poor visibility across the Value Chain _Disruptions or unforeseen events have serious upstream and downstream impacts _Exacerbated by multiple information systems, mostly spreadsheets _Strategic simulation (supply and demand) is often poorly Handled

Nov 1, 2011

By C. D. M. Chisholm

IN discussing stope filling, or backfilling, at the Sullivan mine, at Kimberley, B.C., a brief description of the problem will first be presented. The Sullivan orebody is a replacement in quartzite, with the ore con-forming, for the most part, with the bedding. The dip of the vein, apart from local irregularities, averages about 15 degrees near the outcrop in the southwest section of the mine, and steepens to almost 40 degrees at the northeast end of the mine. The thickness varies from a few feet to over 200 feet at the widest sections. The mineable length along the strike has averaged about 4,000 feet between the 4,600 and 3,900 levels-the section under discussion in this paper. To date, 28,000,000 tons of ore have been mined by the room-and-pillar method. Prior to 1930, all ground opened up had been supported by ore pillars, left during mining operations. From that time, the recovery of the ore from these pillars has been given serious consideration. Backfilling, as being carried on today, is the result of this study and is being done for two reasons: (1) to allow extraction of the ore pillars, and (2) to minimize subsidence of the hanging-wall rock, except where forced caving is found desirable. PRELIMINARY DEVELOPMENTS LEADING TO BACKFILLING When the Sullivan orebody was first opened up, early in the century, there appeared to be low-grade sections of the vein sufficient in extent to serve as permanent support for the roof. However, as mining extended into sections of the vein that showed continuous ore over greater areas, wooden cribs, filled with waste and low-grade ore, were erected. In some stopes, these cribs were as large as 40 ft. by 100 ft. in plan and from 50 ft. to 60 ft. in height, but it was soon realized that this method of support was inadequate. As mining progressed, it was found necessary to leave ore pillars, which eventually became the sole system of support. At first, these pillars were left at irregular intervals, but later they were laid out at definite locations on the mine plans, and these locations were adhered to as closely as mining would permit.

Jan 1, 1941

By R L. Cheesman

An extensive Precambrian iron-formation lies about 2,000 ft. beneath post-Precambrian rocks in the Fort a Ia Corne Forest Reserve, south of Choiceland, Saskatchewan. The geology, deduced from limited drill results and from some geophysical observations, indicates that the deposit is a characteristic magnetite iron-formation, not uncommon in the exposed Precambrian of Saskatchewan, but also shows certain interesting features of faulting and pre-Paleozoic weathering which have given rise to a pre-served detrital deposit of hematite. The body is of ore grade and of sizeable proportions. T HIS paper is presented in order to set forth the interesting geological features of a Precambrian iron deposit located beneath the cover rocks of the Great Plains region and to comment upon the methods of discovery and interpretation of the nature of the body. The Choiceland iron deposit is located in the Fort a Ia Corne Provincial Forest Reserve, some 15 miles south of the town of Choiceland, Saskatchewan. Choiceland is

Jan 1, 1964

By A. P. Fletcher, K. Croteau

The intent of this paper is to cover some aspects of preventive maintenance methods which have come into wider usage in recent years as a means of increasing operating efficiencies. Particular emphasis is placed on lubrication and related servicing.

Jan 1, 1967

By Maciej Wrobel, Joerg Hammerschmidt, Dana Nurgaliyeva, Alexandros Charitos, Jochen Guentner

"Smelting of copper concentrates in the flash smelter generates a flue dust stream that contains a substantial amount of copper and accumulates more than half of the arsenic input to the smelter. In view of its high copper content flue dust recirculation to the flash smelter is common practice. Globally traded copper concentrates are affected by ever increasing arsenic contents and cause an increasing circulating arsenic load in flash smelter operation. Control of the arsenic level in the smelter slag becomes a challenge. This interaction of arsenic loaded copper feedstock, need for flue dust recirculation and slag quality control call for possibilities to reduce the arsenic load of the recirculated flue dust stream.The technology of partial roasting is known from pre-treatment of copper concentrates before smelting, and gold concentrates before cyanide leaching, to remove the harmful element arsenic. The partial roasting technology can be adapted for use in the purification of the flue dust. A major challenge for flue dust treatment is its extremely fine particle size compared to usual concentrates. For this reason Outotec developed a new process, which allows handling of such fine flue dust. This process solution provides an efficient possibility to reduce the arsenic burden in copper smelter operations.The suggested process aims at reducing the arsenic load to the smelter by treating the flue dust prior to recirculation to the smelter. The presented results are based on test work in the Outotec R&D-centre in Frankfurt. It is possible to remove 80-85% of the contained arsenic and to collect it in an arsenic trioxide residue with a concentration above 90%. The final off gas contains SO2 from decomposition of sulphates that are contained in the flue dust. The off gas stream is relatively small. We assume that it is possible to combine the off gas stream with other smelter process gas streams and to treat it in an existing sulphuric acid plant. Coal is used as fuel and as reductant to reduce pentavalent arsenate to trivalent arsenite. Arsenite can be kept in gas form at temperatures above 450°C. This permits separation of a calcine stream with arsenic levels of 0.2 – 0.3%, which is recirculated to the furnace.Outotec has a wide range of roasting testing facilities from lab-scale to pilot-scale. Outotec has both capability to modify and adapt technology to specific ore or concentrate requirements, but also the necessary infrastructure in its research centers in Frankfurt and Pori to do appropriate validation tests in lab and pilot scale size plants."

Jan 1, 2016

By A. W. Jacob

THE shatter cut, or burn cut as it is often called, is one in which the centre of the round is almost reamed out by drilling holes so close together that the blasting of a few holes shatters the rock embraced by all of them. The idea of shattering the centre of a face by shooting holes drilled parallel to one another is not new. Some miners have used this method for years past, when drilling quartz or a face near timber. But, they followed the age-old practice of first blasting the cut, then the square-up. It was not thought possible to shoot both together. In the case of machine men, the two largest contributors to silicosis are dust from drilling and dust from blasting. It follows, then, that material reduction of exposure to either constitutes an important step in lessening the incidence o silicosis. It was? the hope of being able to do away with the necessity of the men having to return early to a face, through dust concentrations of 60,000 to 80,000 particles per cubic centimeter, that aroused interest "in the shatter cut at McIntyre. Efforts to this end were successful. Now, with this kind of cut, all holes of a round are shot simultaneously.

Jan 1, 1942

By Nosa O. Egiebor, Kafui Nyavor

"The effectiveness of sulphuric acid, nitric acid, and hydrogen peroxide pressure oxidation on the cyanide extractability of gold from a double-refractory concentrate is presented. Whileover90% of the sulphide content could be oxidized by either of the two acid pretreatments, only 65% was achieved by the peroxide oxidation. Carbon oxidation by both acid and peroxide pressure oxidation were less than 15%. Although the peroxide pressure oxidation pretreatment resulted in much lower sulphur and carbon oxidation, it gave pretreated residues with decreased levels of preg-robbing activities and higher gold recoveries during subsequent cyanidation, thus indicating some deactivation ofthe preg-robbing carbon during pretreatment with hydrogen peroxide. The refractoriness due to carbon preg-robbing activity was found to contribute more to the refractory behaviour of the concentrate than the occlusion of gold particles by the sulphide mineralization.IntroductionGold ores and concentrates are classified as refractory when a significant portion of the gold content cannot be extracted efficiently by conventional cyanidation, even after fme grinding (Weir and Berezowsky, 1984); (Demopoulos and Papangelakis, 1987). The refractory behaviour of precious metal ores and concentrates is generally attributed to two main factors: The presence of carbonaceous materials which could cause preg-robbing activity during cyanidation (Zaitseva et al., 1973); (Nice, 1971); Scheiner et al., 1971); (Eisele et al., 1983), or occlude gold-bearing minerals (Wells and Mullens, 1973); (Gasparrini, 1983); (Chen and Reddby, 1990), and the occurrence of sulphide minerals which can occlude gold, thus reducing the access of lixiviants (Schwartz, 1944); (Weir et al., 1986); (papangelakis and Demopoulos, 1990); (Michaelis, 1989); (Schweigart, 1965). When the refractoriness is due to a combination of these two factors, the ore or concentrate can be referred to as being ""double-refractory"". Because of the rarity of gold ores exhibiting this double-refractory phenomenon, only a few studies have been carried out on their suitability for pretreatment by existing techniques."

Jan 1, 1992

By E. Yan, M. Mankosa, E. Wasmund

"Rougher flotation in sulfide ore applications is typically performed using conventional flotation machines. The trend over the last 100 years has been for these cells to become larger in volume with cells reaching sizes of 600 m3 and in some cases even larger. The associated foundation loadings, transport and installation requirements along with building size have also increased. In an economic environment where projects must be executed with dwindling capital supply, bigger is not always better. More recently, industry is being challenged to identify new technology that allows for improved flowsheets and financial returns through efficiency gains. To meet this challenge, a novel high-intensity two-stage flotation system known as the StackCell™ was tested to potentially achieve installation volume and required retention time gains when compared to conventional flotation circuits. The results from on-site pilot scale work conducted on typical copper concentrator rougher flotation feed showed retention time gains on the order of 6 to 9 times when compared with conventional flotation equipment. This finding has the potential of reducing capital demands for rougher flotation circuit designs when incorporating the StackCell. The results from test work will be discussed in this paper showing comparative test data generated with a Denver bench batch test, pilot StackCell and large conventional cells, all receiving the same feed.INTRODUCTION Over the last few years, a number of flotation devices have been described as two-stage or multi-stage flotation units. The idea behind multi-stage flotation devices is that flotation performance can be improved by utilizing cells with multiple specialized units in series, but not all units of the same type, as is practiced in trains of multiple tank cells or columns. Instead, each unit is specially designed to provide the optimized fluid environment for each stage of the sequential flotation process. This idea has been proposed based on a study of the fundamentals of the flotation process, and the realization that the process consists of discrete sequential processes, that are each optimized with dissimilar process conditions (Finch et al, 1995), (Zhou, 1996). Instead of executing each step simultaneously in a homogeneous fluid environment, where the conditions would be a compromise between particle collection and froth recovery, the multi-stage flotation unit operates in a set of segregated process environments, each with a set of conditions optimized for that step."

Jan 1, 2018

By J. Font

The RAF or copper fire refining process at the Caletones smelter of CodelcoChile consists of several pyrorefining stages that successively lowers the levels of S, Fe, Pb, As, Sb, Te, Se and to some extent 0 in the copper melt, allowing the production of high quality fire-refined copper of 99.93 % purity (RAF copper). This chemical feature of the RAF copper is only achieved by quite long processing times, and a considerable consumption of fluxes and fuels in the RAF vessels. The main goal of this study was to improve the RAF process performance by thermodynamic considerations and industrial scale tests, i.e., an in situ approach for the process as featured by intensive sampling, characterization and subsequent modifications. Thus, both theoretical and industrial data were derived, and based on kinetic and thermodynamic evaluations, a higher operational standard was achieved for the RAF process. These new operational practices allowed enhancing the overall economic of the RAF process, by reducing the time and operational costs, and consequently increasing the availability of the vessels.

Jan 1, 2007

By J. T. McGrath, R C. A Thruston

The structural changes which take place in polycrystalline copper under the action of alternating cycles of torsion stress were studied, using the optical microscope and the X-ray dif-fraction camera, and an attempt was made to correlate them with changes in the shape of the cyclic stress-strain curve. It was found that the period of work-hardening was less than one per cent of the fatigue life, and that persistent surface marking, which are assumed to be incipient or actual microcracks, occur upon completion of work-hardening. X-ray diffraction patterns revealed considerable grain distortion at the completion of work-hardening in specimens cycled at a high strain amplitude. This distortion became progressively less as the strain amplitude de-creased. Mechanisms for the completion of work-hardening and the formation of microcracks are discussed.

Jan 1, 1962

By Binbin Luo, Northeastern University, Chuanyao Sun, Jie Liu, Yimin Zhu, Yanjun Li

"A series of new type collectors a-bromo-saturated fatty acids, CH3(CH2)5CHBrCOOH (a-BHA), CH3(CH2)7CHBrCOOH (a-BDA), CH3(CH2)9CHBrCOOH (a-BLA), CH3(CH2)11CHBrCOOH (a-BMA) were synthesized from saturated fatty acids and bromine by solvent-free method (Hell-Volhard-Zelinski reaction) in laboratory. The micro-flotation tests of quartz mineral were conducted at a relatively low temperature of 15 °C. The adsorption mechanism of such collectors on quartz mineral surface were established by zeta potential measurements, in conjunction with the results of quartz micro-flotation tests. The flotation results showed that the collecting ability is in the order of a-BMA > a-BLA > a-BDA > a-BHA for the flotation of quartz mineral, which also demonstrating that the a-bromo-saturated fatty acids (a-BFAs) are new selective collectors for reverse flotation to remove quartz mineral from iron ores at a relatively low temperature.INTRODUCTIONThe requirement of higher pulp temperature to maintain the activity of fatty acid anionic collectors which have been widely applied in technological process of iron ores reverse flotation lead to a great deal of energy consumption.The purpose of this paper is to synthesize a new modified collector with carbon chains from eight to fourteen atoms, with strong electronegativity bromine atom introduced into a-carbon position to improve the activity and solubility of the reagent so that it can be adopted at a comparatively low pulp temperature. The collecting performances of these new collectors on quartz surface were studied, and the structure - properties were discussed in light of zeta potential measurements and quantum chemistry calculations."

Jan 1, 2016

By J. H. Fulton

Summary Considerable test work has been done with the detachable type of carbide bit. In general, these bits improved drilling operations, but at a bit cost .greater than was compensated for by the reduction in man-hours of labour. Too few bits continued in service for the possible drilling life of the carbide inserts, and technical improvements or lowered first cost, preferably .both, are indicated ?in order that the bits can be generally acceptable as an economical drilling tool. In ?preliminary test work, the drill rods .with ?one insert of the chisel-bit type appear to be more trouble-free, to have a longer life, and to give a somewhat lower bit cost per foot drilled, than other types. INTRODUCTION The object of this paper is to outline briefly the 'methods used and the results obtained in test work with tungsten carbide bits used in combination with the smaller bore, lighter weight rock drills. As various articles have appeared in the past few years giving the historical background ?and early development of carbide ?bits, this information will not be repeated. Table I lists the equipment used in the test work. The stopers weigh about 95 pounds and the jackhammers with airleg from 97 to 110pounds. The smaller rock drills are stated to deliver about 2,200 blows per minute at 1 to 30 rotation and to require 85 to 95 cubic feet of air at around 100 pounds pressure.

Jan 1, 1950

By R. R. Irrinki

Abstract -The Key Anacon deposit consists of four sulfide zones called, from south to north : Key Anacon No. 1, Key Anacon No. 2, Key Anacon No. 3, and Key Anacon Copper Zone. Massive sulfides of zones 1, 2, and 3 are underlain by rocks correlated with the Nepisiguit Falls Formation and are overlain by matie volcanic rocks correlative with the Boucher Brook Formation. In contrast to zones 1, 2, and 3, narrow northwesterly-trend.ing, copper-rich fracture zones occur within the Patrick Brook Formation. Sulfides in zone 2 occur as three mineralogical associations, namely: pyrite-chalcopyrite, pyrite-sphalerite-galerta, and pyrrhotite-sphalerite-galerta. The distribution of lithologies and en-echelon patterns of the three sulfide lenses of Key Anacon No. 2 zone are the result of F1 and F2 folding. Zone 2 is the most promising economically, with proven reserves of 1.11 million tonnes grading 0.2207o Cu, 3.47% Pb, 8.41% Zn, and 96 g/t Ag; the zone is open below a depth of 427 m.

Jan 1, 1992

By T. T. Ni

FOR MORE THAN 200 years, the Kochiu district of Yunnan province has been, and it still is, the hub of China's tin industry. The district produces annually from 80 to 90 per cent of that country's out-put of tin, which averages about 9,300 tons a year and places China fifth among the tin producing nations of the world. The tin ore reserves of the country are estimated (1) at 1,873,370 metric tons, of which 1,500,000 tons are in the Kochiu district. The mill of the Yunnan Consolidated Tin Corporation, described in this paper, is the only one of its kind in China. MINING AND SMELTING There are only two tin mines in the Kochiu district operating with modern equipment -the Hsin-Chang and the Lao-Chang, both owned by the Yunnan Consolidated Tin Corporation, a government company. The Hsin-Chang mine has four working levels with cross-cuts 6 ft. by 6 ft. and is equipped with steel mine cars and trucks to haul the ore. The ore is hoisted to surface in a three-compartment shaft and transferred to the mill by a 4-kilometer aerial tram. The Lao-Chang mine has two circular shafts 656 feet apart, each equipped with two cages. Haulage-ways 1,600 meters and 1,000 meters long, respectively, have been driven to the southwest from these shafts and are connected by three cross-cuts.

Jan 1, 1951

By C. Doyle, D. M. Hoffman, C. Díaz, J. Hrepic, W. J. Koshut, R. H. Hanewald

"Recently, lining life of the INMETCO submerged arc furnace has been dramatically extended from an average of eleven months in the 1980s to a current record of 34 months. This paper summarizes test work and operating results describing the development and establishment of slag parameters that reduce corrosion of the magnesite-chrome refractory lining.The desired slag parameters are now maintained by utilizing waste streams as slag additives. This paper also discusses the successful evaluation of a rebonded-fused-grain magnesite- chrome refractory as a lower cost, more thermo-mechanically forgiving alternative to a fused-cast magnesite-chrome refractory that had been the refractory of choice in previous years at INMETCO.IntroductionSince 1978, INMETCO, a wholly owned subsidiary of INCO Limited, has been well known for recycling by-products from the production of stainless steel, namely, EAF bag- house dust, mill scale and grinding swarf. INMETCO operates the only smelter in North America dedicated to the recovery of nickel, chromium, and iron from hazardous and nonhazardous waste. The process was developed in the research laboratories of INCO. In recent years, the process has been successfully modified to accept a wider variety of other specialty steel waste streams including: spent pickling solutions, pickling and waste water treatment filter cakes, acid scale, carbon brick, spent bag-house bags, torch cutter dust, spent dolomitic and chromium-bearing refractories, and rechargeable nickel-cadmium batteries."

Jan 1, 1997

By J. Ramirez-Castro, J. A. Finch

"Galena is the finest component of the product of a closed-circuit grind treating a lead-zinc ore, largely due to preferential recycling of this high-density mineral by the cyclone. For example, at the Pine Point Mines concentrator, for ~ 55% -200 mesh over-all, the galena will be close to 95% -200 mesh. This sliming of the lead can limit recovery, selectivity and dewatering. A proposed circuit modification to reduce the sliming is to incorporate a unit cell. A simulator was constructed to study the No. 3 grinding circuit at Pine Point modified by a unit cell on ball mill discharge (BMD).The simulator used a cumulative size basis rate-of-breakage with plug flow ball mill model, the parameters being obtained by laboratory grinding tests. Flotation and the cyclone models used a cumulative recovery/size matrix. The behaviour of each mineral, galena, sphalerite, pyrite and calcite/dolomite, was simulated. Simulation was adapted to a programmable calculator. A close fit to the existing circuit performance at two tonnages and mineral mixes was established.The simulator showed that the modified circuit could significantly coarsen the Pb grind, from 95% to —50% -200 mesh, depending on recovery, without substantially altering the size of the other minerals. The other principal findings were: compared to laboratory flotation tests on existing circuit BMD, the unit cell concentrate (CONC) will be coarser and markedly lower in grade; relatively low unit cell stage recoveries are desirable, because the cyclone scavenges the tail to give a circuit recovery which is higher than the unit cell stage recovery; unit cell stage recovery should not exceed the cyclone stage recovery, as the latter is the maximum circuit recovery; low unit cell stage recovery helps offset the disadvantage of the high flow at BMD; other high-density minerals will also be scavenged into the CONC, as illustrated by pyrite, making CONC quality difficult to maintain; density control of BMD flotation does not greatly alter feed density to the cyclone or ball mill.Possible plant metallurgy is forecast for a CONC diverted to final lead concentrate."

Jan 1, 1980

By A. S. Robb

SAMPLING of an ore-body is one of the fundamentals in its exploration, development, and exploitation. It is carried out to determine the gold value per ton of an ore-shoot and the probable gold output of the refinery. Sampling also places any broken ground in one of two classes, ore or waste. The value and importance of correct sampling has been shown repeatedly in the past. On the other hand, instances could be given where those in charge of mines have not believed in sampling, and the result has been the same in every case-disaster. This has in all probability been due to assuming that good-looking, well-mineralized rock was ore. Sampling in some form might have averted this misfortune. In this essay, only the method of sampling and the estimation of ore reserves is treated. All titles, figures, and values are fictitious. None of the illustrations can be directly applied to any portion of the Hollinger mine, except Figures 1 and 2, which are included with the special permission of the Canadian Mining Journal. METHODS OF SAMPLING Hollinger Consolidated Gold Mines, Limited, has, from the very beginning of operations, carried out an extensive system of sampling, and the results of this sampling have completely governed the whole mining programme. The Hollinger discovery was made in 1909 and prospecting and exploration of 'the surface began at once. Four men were given jobs as samplers and they sampled thoroughly all the outcrops and all bed-rock which could be exposed to view by removing the overburden. When shaft sinking began, samples were taken at two-foot intervals. In 1912, an underground gang of six samplers was organized, and the number was increased at a rate of about two men per year as the size and extent of the workings grew. No permanent record of sampling was kept until 1919, in which year an average of 11.6 men took 28,458 samples, cutting 113,894 feet of sample. From that time until the end of 1934, the average number of samplers varied, but the total number of samples cut, and the total footage sampled, increased.

Jan 1, 1937

By P. F. Venus

In December 1977, a large pillar was removed by blasthole mining methods at lnco's Creighton No. 3 mine. Although the 2,363.000-ton blast was not a size record for a single underground blast at Inco, it did represent a significant departure from conventional blasthole mining. In terms of the application of nominal 6-inch-diameter boreholes underground, coupled with bulk slurry explosives, the magnitude of the blast is considered a first and very important development. The application of large-diameter boreholes in underground operations was first tried successfully in 1973. Since that time over 13/4 million feet have been drilled in this adaptation of an open-pit technique to underground operations. The blast, which required 708 holes, totalling 131,500 feet of drilling, was loaded in a six-week period, using special slurry handling techniques developed jointly by Inco and CIL. Inco operating and engineering personnel consider this application of large boreholes and slurry explosives for blasthole mining a very important milestone in modern mining technology.

Jan 1, 1978

By G. A. Gross

"The Soviet Union has enormous reserves of iron ore in many different kinds of deposits that are widely distributed in this vast land area. The present iron ore industry is based mainly on deposits in Precambrian cherty iron-formation at Krivoy Rog, Kursk and Murmansk. Extensive reserves of both naturally enriched hematite ore and magnetite iron-formation in these areas alone could sup-ply all the domestic ore required for several hundred years.Many contact metasomatic magnetite deposits discovery in recent years in the eastern Ural Mountain belt and east of the Kusnetsov basin in Siberia are being developed, with ore reserves measured in billions of tons. Oolitic limonite-chamosite-siderite ores of Cretaceous and younger age at Kerch on the Black Sea and around the east and southern perimeter of the West Siberian basin constitute some of the largest concentrations of iron in the world. These sedimentary ores are low grade, of poor quality and difficult to beneficiate. Banded jasper magnetite and hematite iron-formation in volcanic rocks of Devonian age in Kazakhstan and along the Mongolian border are of special geoloica1 significance.Iron deposits in the Krivoy Rog and Kursk areas were examined and a large number of geologists discussed their work on deposits in many other parts of the Soviet Union during the writer's seven-week study tour of mines and research institutes in Moscow, Leningrad, Novosibirsk in Siberia and Kiev in the Ukraine. The descriptive geology of iron deposits of useable ore and of marginal material has been well documented in the course of systematic work and a large number of scientists are studying fundamental problems on the origin and treatment of iron ore."

Jan 1, 1967