Search Documents

By Neil Schofield

"The estimation of recoverable ore reserves for feasibility in precious metal deposits such as Pine Creek must account not only f or the extreme variability of the ore grade but also for the complexity of the geology. Compatible models f or both must be adopted. Further, very selective mining demands reserve estimates be based on small selection units whose individual grades cannot be estimated reliably from the exploration drilling data.Multigaussian kriging is one method based on a multivariate normal model for estimating recoverable reserves under such conditions. In this paper, a non-mathematical description of the multigaussian model is presented together with its application to the Pine Creek Gold Deposit. The results, when compared to the first year of production, are encouraging for the model but not without surprises.Together, Part 1 and Part 2 of this study combine a detailed and geologically conditioned variogram analysis with an appropriate estimation method for a highly variable low-grade gold deposit. This and other studies of gold deposits familiar to the author show convincingly both that while the appropriate geostatistical skills and techniques are necessary to tackle the question of reserves, equally important but often discounted is the need for an appropriate and compatible geological model. IntroductionThe Pine Creek gold mineralization is associated with saddle reefs, and quartz and quartz- sulphide veining within the Enterprise Anti cline. The anticlinal structure is complex and, prior to mining, the mineralization was considered to be mainly strata controlled. Grades vary up to 160 grams in l .5rn core samples with coefficients of variation in excess of three.The estimation of the recoverable reserves for such a depo sit must account for both the geological complexity and the extreme variability of the gold grade.Part 1 of this work presented the geological model for the deposit and summary statistics 0 f the gold data. A detailed structural and variogram analysis considered both gold grades and the normal score (or gaussian transform) of these gold grades for different composite sizes."

Jan 1, 1988

By G. H. Montgomery

THE PROPERTY of Aunor Gold Mines, Limited, consists of eleven claims, located in Deloro township, approximately three miles southeast of the town of Timmins. Production began in 1940 and currently the mine is operating at a rate of 485 tons per day. GEOLOGY AND MINE DEVELOPMENT The ore zone at Aunor occurs in altered lavas bounded on either side by soft talc-chlorite schist, locally known as 'soapstone'. The zone has a strike of N.80°E, dips 60° North, and varies in width from 0 to 250 feet. Within this zone the main orebody has a westerly plunge, away from the No. 1 shaft area (Figure 1). The mine is developed by a vertical three-compartment shaft from surface to the 3,082-foot horizon. Working levels are spaced at 125- foot intervals from the 625-foot to the 1,625-foot horizon, from which to tl1e 2,125-foot level the interval is 250 feet.

Jan 1, 1957

By W M. Gilchrist

This paper gives an estimation of the future requirements of the western world in relation to energy re-sources. It then goes on to outline the role that atomic power -with its basic raw material, uranium -will play in supplying these energy requirements. Canada's position in this picture is covered, and some interesting forecasts are made. Introduction I T is possible that the following remarks will appear to have more to do with power than uranium. However, to fully comprehend what is in store for the Canadian uranium mining industry, we must be able to estimate the potential requirement, and, to do this satisfactorily, a thorough understanding of the circumstances that will give rise to that demand is necessary. The growing need for electrical energy will play by far the major role, as large tonnages of uranium will be required for its generation. The nuclear weapon has, up to the present, comprised the major market for uranium.

Jan 1, 1964

By D. Bouchard, M. Forté, A. Charette

A transparent replica of a casting die was built to achieve a better understanding of the filling mechanisms of aluminum in high pressure die casting. Water and tomato paste were respectively used as analogues for the Newtonian liquid aluminum and the non-Newtonian semi-solid aluminum. The transparent die was installed on an industrial casting press and filling was filmed with a high-speed camera. Differences between the Newtonian and non-Newtonian fluids are presented and discussed.

Jan 1, 2006

By J. M. Wetherill

"This paper presents the results of an investigation into the level of radon, as against the natural background, at the Vicary Creek coal mine in Alberta. The concentrations of radon and daughter products detected in the mine were considered to be insignificantly higher than the concentrations of naturally occurring radon and thus do not constitute a health hazard to the miners.INTRODUCTIONTHE HIGH INCIDENCE OF LUNG CANCER among miners exposed to radon was established some thirty years ago. The presence of this gas in mines is primarily associated with pitchblende extraction operations, al-though coal contains detectab`e quantities of U30s. A previous study bas shown that coal from southwestern Alberta (Exshaw and Banff) contains lower than average concentrations of this element (1).As part of a general investigation into the occupational health environment of coal miners in Alberta, field measurements were made to establish the level of radon and to investigate the natural background radiation in the Vicary Creek coal mine, located some 16 miles north of Coleman, Alberta, on the easternmost slopes of the Rocky Mountains."

Jan 1, 1968

By D. Ibarra, J. Jacob, A. G. Guezennec, P. d’Hugues, A. Archane

The lack of adequate gas mass transfer is a rate limiting step in many bacterial leaching processes. Oxygen often becomes a limiting factor because of its low solubility compared to the high demand induced by sulfide oxidation. One way of increasing the solubility of oxygen in water or in media solution is by increasing the driving force, i.e. raising the oxygen partial pressure in the gas stream supplied to the leach pulp. The use of oxygen is a well-known practice in high-temperature bioleaching reactors (above 70°C) whereas air is usually preferred in medium and low-temperature operations in order to avoid too high dissolved oxygen concentrations which could impact negatively the bacterial activity. The purpose of this study was to investigate the use of oxygen-enriched gas in bioleaching reactors at 40°C in order to improve the gas transfer in the system when operating at high solid load (20% and more). Bioleaching experiments were performed on a sulfide-rich tailing waste (pyrite 60%, copper 0.8%, cobalt 0.06 %, gold 1 g/t) using the “BRGM-KCC” bacterial consortia. The reactor used for the tests was designed on the basis of a new bioleaching reactor concept developed by Air Liquide, Milton Roy Mixing and the BRGM which uses floating agitators to inject gases and to mix and to suspend solids in the bioleaching solution. Two types of tests were carried out: with air injection and with oxygen enriched gas mix injection. The aim of this work was to confirm the capacity of bacteria to grow and to dissolve pyrite in this type of bioreactors in oxygenrich atmosphere, and to compare sulfides dissolution rates during both types of bioleaching tests. The results obtained show that the use of oxygen enriched gas mix does not decrease bioleaching performances compared to air injection. High metal extraction yields were achieved (above 80%). No deleterious effect due to oxygen use was observed on the bacteria despite the high level of dissolved oxygen reached in oxygen tests (up to 14 mg.L-1).

Jan 1, 2016

By M. Mirzazadeh

Air cooled crackable and conventional forged steel specimens were tested under reversed push-pull conditions to examine the effect of shot-peening on their high cycle fatigue behaviour (-106 cycles). The steels were tested in the normalized as well as shot-peened conditions. The results showed that shot-peening smooth specimens had little effect on the fatigue limit of the air cooled forged steels and the detrimental effect of the rougher peened surface was not apparent. Microhardness profiles indicated that the shot peening produced a gradient of compressive residual stresses that was greater than that of the loading stresses, suppressing the anticipated beneficial effect on fatigue life. Crack initiation was more likely to occur below the surface. The results indicate that the surface roughness was not a significant factor in controlling the fatigue lives, since they were essentially the same for the non shot-peened and shot-peened steels.

Jan 1, 2010

By T. Alan O'Hara

"Annual mining revenue can be computed by formulae relating metal prices, smelting schedules, concentrate grade and recovery to known ore grade and an assessment of core samples. Operating costs at different daily tonnages are related to orebody shape, mining method, milling process and general plant services. Capital costs are related to sizing of mining equipment, mine development, plant-site topography, climate and accessibility, plant services and personnel housing. IntroductionA crude guide to the average 1978 cost of mine projects is shown in Figure 1, but the costs of many mine projects have differed widely from the graphed average costs of $800,000 T0.6 for underground mine/mill projects and $400,000 T 0.6 for low-grade open-pit mine/mill projects.High mine project costs and high operating costs are characteristic of open-pit mines with high stripping ratios, underground mines with thin orebodies, mills with complex metallurgy, and projects located in isolated regions with severe climate, mountainous topography, and lacking access to existing roads, towns and electric power. When none of these adverse conditions prevailed, the mine project cost was typically much less than the graphed average cost. Virtually all the conditions likely to cause high capital and operating costs are known from knowledge of the local topography, climate or accessibility, or can be assessed by tests on core samples, as soon as the orebody has been outlined by drilling .A more accurate estimate of over-all project capital cost and operating cost can be made from a summation of items of cost after judging the effect of specific local conditions on each item of capital and operating cost. This paper offers guides in judging the effect of local conditions on the sizing and 1978 cost of specific items of capital cost and operating cost and operating cost of mine projects. When the specific items of capital cost and operating cost are totaled and measured against expected net revenue and taxes over the life of the mine using the net-present-value or discount-cash-flow methods, the result should show whether the mine project development is clearly feasible, doubtfully feasible or clearly uneconomic. If the development of the mine project is clearly feasible, or probably feasible, a detailed feasibility study by experienced consulting engineers should be commissioned before any financial commitments are made; but if project development appears to be uneconomic, the time and cost of a detailed feasibility study is not warranted."

Jan 1, 1980

By H. C. Cooke

This paper will discuss two comparatively unrelated subjects; first, a general review of the advances made at the more important properties in the last year; and second, a statement of the conditions controlling the deposition of the copper ores in the Rouyn area, as determined by last summer's field work. FIRST PART Development has been very rapid since I stood before the Institute one year ago to discuss this same subject. Then, there were many properties on which gold had been discovered, any of which might develop into a mine. Further work has eliminated the most of them as possible mines, or at least has shown that before they can attain that status further discoveries must be made on them. Then, all gold veins held forth much the same promise; now the indications are that one particular type of gold vein is of greater prospective value than others. Then, all eyes were turned toward gold as the metal of prime economic importance; now copper has taken the centre of the stage, and gold is distinctly in the background.

Jan 1, 1926

By Donald MacFadgen

Since 1950, a total of 164 miles of levels and rooms have been roof-bolted in the collieries of the Dominion Coal Company. Roof bolting is an efficient and economic method of sup-port where heavy timber sets or steel booms are necessary for temporary roof support, or where conventional methods of support interfere with the passage of mechanical mining equipment. This paper discusses present roof bolting practices and special bolting applications. THE practice of roof bolting in be collieries of the Dominion Coal Company dates from 1950, when preliminary studies and experiments were carried out in a mechanized room and pillar section of Dominion No. 20 Colliery. These studies were made in close liaison with members of the United States Bureau of Mines who were conducting similar studies. Following the successful application of roof bolting in No. 20 Colliery, this method of roof support was introduced into other collieries

Jan 1, 1963

By C. D. Anderson, C. G. Anderson, P. R. Taylor

"Rare Earths have become critical for our energy and materials driven society. While primary production must ramp up to fill growing demands, the recycle of these strategic elements must also be initiated. This paper will outline the potentials of and metallurgical technologies employed for Rare Earths recycle from various secondary sources.INTRODUCTIONWhen investigating the recovery of rare earths from secondary sources it is necessary to understand the nature of the sources to be processed. As of 2009, the USGS reports the distribution of rare earths by end use, in decreasing order, was: chemical catalysts 22%, metallurgical applications and alloys 21%, petroleum refining catalysts 14%, automotive catalytic converters 13%, glass polishing and ceramics 9%, rare earth phosphors for computer monitors, lighting, televisions 8%, permanent magnets 7%, electronics 3%, and others 3% (USGS, 2011). Additionally, it is reported that the amount of recycling was quite small and consisted primarily of rare earth magnet scrap, although with the sharp increase in the price of rare earths, and the potential shortage in supply, focus in this area is continually growing. Thus, the opportunities, whether realistic or not, are extremely vast in the recycling of rare earth containing materials. The following subsections will present methods proposed for the recycling of rare earths based on the feed material type.RECYCLING OF RARE EARTH MAGNETSCurrently, investigations are ongoing in the area of recycling production scrap and end-of-life materials in the rare earth magnet industry. The following techniques illustrate potential methods for the recovery of rare earths from secondary RE magnet sources.Recycling of Rare Earth Magnet Sludge by Selective ChlorinationDuring the production of neodymium magnets, a by-product of production is the so called “magnetic sludge”. This by-product contains high amounts of neodymium, thus a process for the recovery of Nd has been proposed. In this process the Nd present is selectively chlorinated/distilled by the addition FeCl2 via the following reactions."

Jan 1, 2012

By H. Sahay

"DISCLAIMER NOTICEThe views and conclusions contained in this presentation are those of the author and should not be interpreted as necessarily representing the official policies or recommendations of the Department of Mines and Energy, Government of Newfoundland and Labrador. ABSTRACTThis paper describes the main testing procedures that should be carried out to evaluate the capacity and capability of the service brakes on the large-size diesel-electric trucks now in common use at open-pit mining operations. Brake testing programs in general are described, and then consideration is given to different techniques of service brake testing, brake performance evaluation, braking energy and typical performance characteristics.IntroductionThe first diesel-electric truck with a capacity of about 85 tons was introduced in 1963 by Unit Rig and Equipment Company of Tulsa in cooperation with General Electric Company, who successfully developed and supplied the most important component- motorized wheels. Since then, its popularity and numbers have continued to grow, and now more than 3700 such units are in operation in mines around the world. In Canada alone, their number is more than 700, including about 150 in the Province of Newfoundland and Labrador. Similarly, their size has also grown from that initial capacity of 85 tons to 350 tons.Although the introduction of the electric trucks proved to be invariably economical, their indiscriminate use was not without severe consequences. Many runaways and even fatalities occurred when the dynamic retarder failed while the truck was travelling loaded down severe grades. The service brakes in such cases proved incapable of stopping runaway trucks, mainly due to their limited capability and the fading caused by excessive heat produced during the act of braking itself. This eventually led the various governments, the open-pit operators and the manufacturers to seriously question the braking capability as well as function of both service brakes and dynamic retarders. Extensive testing"

Jan 1, 1980

By T. Patching

"THE FOLLOWING notes on coal mining in the Edmonton city area are based, in the main, on scattered reports and accounts as little coal mining has been done in this area for about 20 years and few people are left who were involved in what was at one time an important industry of northern Alberta. Although coal mining is not likely to be permitted in the city area itself in the future, a record of this work is warranted to indicate the ·conditions and problems that may be encountered if underground mining again is proposed in the district in the same geological formations and in similar strata. Coal mining in the Edmonton area developed with the influx of settlers in the latter part of the nineteenth century and the first part of the present century. Probably local coal was used by the Fort's blacksmith as early as 1841, and the early settlers probably were 'gopherholing' into the outcrops along the river banks by the 1870s. The first report of commercial coal mining was in 1880 when a contract was let by the Hudson's Bay Company for the provision of 300 tons. As the population in the city and northern parts of the province grew, many new mines were opened along the river and in the district, and coal was even shipped by barge to points in Saskatchewan(1 ,2) By 1909 the Department of Public Works reported that 'Edmonton stands as the second largest domestic coal producing centre in the province'. It continued to hold this position until 1942. From about 1912 to 1951 annual production from mines in the city and surrounding district ranged between 0.38 and 0.65 million tons, depending on weather, wars and strikes. Production began to decline in 1951 because of the increasing availability and consumption of natural gas which was piped into the city and then provided to other towns and rural areas in the northern part of the province. Taylor noted that between 1880 and March 1970, when the last mine within the city area closed, the total of mines and prospects within the Edmonton city area rose to 153. Most of them were small; not more than 20 produced more than a quarter of a million tonnes during their entire life, and only three produced a million tonnes or more. As described by Taylor ""within the city district workings extend discontinuously from the apex of a narrow triangle near Groat Bridge to the base of the triangle in the Clover Bar area"". The larger mines were in this latter area. Approximate locations of the old mine workings in the city are shown in Taylor's atlas. A number of other coal mines were worked in the Rabbit Hill, Big Island, St. Albert, Namao, Cardiff and Morinville districts around the city."

Jan 1, 1985

By O. Babak, J. G. Manchuk

ABSTRACT A significant factor in evaluating bitumen recovery from an oil sands mine is the particle size distribution (PSD). Increased understanding of mined ore quality and improvement in predictions of recovery can be achieved through PSD modeling. This paper addresses PSD modeling using geostatistics. PSDs may be described using many discrete particle sizes, making this a challenge. The approach parameterizes PSDs with a few statistics. A lookup table is used to reconstruct the PSDs based on models of the statistics. The workflow is applied to Total E&P Canada’s Joslyn Lease and yields good results that reproduce input statistics without introducing artifacts.

Jan 1, 2013

By A. K. Debnath

The water resource is key to survival of the mankind and this resource is now becoming critical in many parts of globe including India. As per an assessment of Central Ground Water Board (CGWB) of India, a huge shortfall of about 58 billion m3 of water is anticipated by the year 2050. In order to counter this shortfall, there is thrust from Government of India to adopt water conservation measures. National Environment Policy, 2006 of Government of India also stresses upon the need to take up water conservation measures for water security of the country. The coal mines in India provide an excellent opportunity to take up water conservations measures therein. The mine water is not acidic unlike western countries and it conforms to the prescribed regulatory standards. This nature?s gift is utilized in Coal India Limited by allowing mine voids to get filled with mine water. The net recharge potential of the opencast mining area is found to be about 5% in comparison to 2% in non-mining area offering good prospects for ground water recharge. The seasonal rainwater is also diverted into mine voids left at the end of mining operations which act as huge reservoirs/ pit lakes for storage of the water. They also serve as surface water bodies for recharging of water table in the surrounding areas. The area and space left from where coal has been extracted completely in underground mines and will not be entered by any man or machinery after the extraction, called goaf, are also potential source of water conservation. These additional water resources created are being utilized for meeting the industrial, domestic, irrigation and other requirements of the projects and local communities eliminating the need to tap other fresh water resources including ground water. Presently, 75% of the water demand of the coal mining project is being met from the water stored in the mine pits. In future, CIL is likely to create about 3.3 billion m3 of water resource, on an average, in its opencast mines alone. In the mine closure plan of opencast mines, the last cut is proposed to be developed into water body for recharge of ground water and creating additional water resources. A clean potential source of potable water is thus developed after mine closure. This will ensure water security of the country.

Aug 1, 2013

By V. I. Lakshmanan, I. G. McColl

"Heap leaching of gold ores in permafrost conditions is feasible provided certain criteria are met. These criteria include relatively short heap leach residence time and the availability of waste heat.This paper describes the conceptual design of such a system for a mining operation in the North West Territories of Canada. The design includes the concept of continuous countercurrent leaching in enclosed ore heaps.Indicative capital and operating costs are given.INTRODUCTIONIn April 1984, Acres Davy McKee Engineering Inc. (ADM Eng.) in association with Ontario Research Foundation (ORF), was invited to carry out a preliminary design, cost estimate and financial analysis to assess the viability of gold heap leaching in a permafrost region in North West Territories, Canada.An orebody was being explored which could, by nature of its mineralogy, be upgraded substantially by crushing and screening in the size range of 1/4 in. to 3/4 in. It was proposed to process the screen undersize through an existing gold mill on site and to treat the oversize material in a heap leach facility to be constructed adjacent to the existing mill.Despite the formidable challenges imposed by isolation, permafrost and harsh winter conditions, the heap leach project was considered worthy of examination because of the relatively high grade of the heap leach material (> 0.1 oz/ton), very short leach times (in the range of 1 to 4 days) and the availability of substantial quantities of waste heat from the diesel generating station on site.Design challenges included the necessity to maintain the permafrost in frozen condition, to prevent freezing of ore and leach solution, to limit size of construction materials to that which could be carried in a Hercules freight plane and to contain water usage at an absolute minimum level."

Jan 1, 1987

By Samuel O. Akande

"Gold occurs as native metal, in electrum, and in a telluride mineral in quartz carbonate veinlets of three vein systems at the Ross Mine, northern Ontario. The 14 Vein System is made up predominantly of concordant veinlets within layered ankeritic dolomite stratabound by, and conformable with, andesite tuff Individual veinlets contain pyrite, sphalerite, galena, chalcopyrite, tennantite, pearceite, proustite, native gold and electrum in a matrix of quartz, dolomite, ankerite and calcite. The 2B Vein System is made up of both concordant and discordant veinlets within andesite tuffs. The veinlets contain pyrite, chalcopyrite, sphalerite, bornite, tennantite and free gold in quartz, calcite and dolomite. The 18 Vein System is comprised of stockwork veinlets in and around intrusive syenite which has both sharp and gradational contacts with enclosing andesite tuff The veinlets contain pyrite, chalcopyrite, bornite, chalcocite, native gold and calaverite. Sulphide and silicate minerals in veinlets and wall rocks are stable assemblages for the regional metamorphism of greenschist rank. ,The 14 Vein System is interpreted as a metalliferous siliceous carbonate chemical sediment, the components of which were leached from the underlying volcanic rocks by convecting sea water and subsequently deposited on the sea floor between the extrusion of flows and pyroclastic rocks. Subsequent regional metamorphism and intrusions remobilized and redistributed the syngenetic stratabound material into dilatant fractures in adjacent tuff, as in the 2B and the 18 vein systems."

Jan 1, 1982

By DON E. MacDONALD

Marl in Alberta is confined to highly specific geological, hydrogeologica/ and climatic settings. Tufa is fa irly abundant in those areas of western Alberta where bedrock is of the Paskapoo Formation. Marl and tufa originate when the following conditions are met: presence of a carbonate source in drift or nearsurface bedrock; leaching of the carbonate by percolating groundwater; transportation of calcium and bicarbonate ions in a permeable aquifer; discharge at the surface as springs, seeps or lakes; re-precipitation of calcium carbonate. Alberta has seven categories of marl and tufa deposits, based upon over-all depositional environment and calcium carbonate

Jan 1, 1984

By O. Lundhede

Today, systems and machinery usually are designed to meet only one specific customer?s requirements. One reason for this is that underground automation and smart functions are often developed tightly together with a customer. This is natural, since risk and cost can be shared between the customer and the supplier. Nevertheless, when the automation product develops and the market increase this will cause problems: The highly specialized products will not fulfill the next customer?s demands. In order to cope with this problem, Atlas Copco works towards a common platform. Instead of designing solutions for specific customers, we will lift the abstraction and focus on standardized modules. These modules, or function blocks, can then be combined in a large variety of configurations. The benefits of combining modules into products are, for example: increased flexibility when options are available for many machines; easier commissioning and maintenance since less different spare parts and tools are needed; and easier operation since the user interfaces have a similar look and feel. This paper will present the ongoing work towards standardized modules. We will discuss how our Rig Control System (RCS) allows for modular design at Atlas Copco. RCS has number of standardized modules that are used in different surface and underground mining and tunneling equipment. These modules are also used for optional products such as, drilling, radio-remote control, and telematics systems.

Aug 1, 2013

By R. F. Robertson

"Adsorption isotherms of hexyl mercaptan vapour on synthetic sphalerite, zinc sulphide and zinc oxide were de-termined with a gravimetric McBain-Baker micro balance incorporated in the B.E.T. apparatus. Isotherms are given for hexyl mercaptan on synthetic sphalerite at 25°C, 0.5°C and 50°C; on zinc sulphide at 25°C and 1.5°C; and on zinc oxide at 25°C. All these isotherms are sigmoidal, with a definite change in slope at or close to the mono-layer. The amount of mercaptan adsorbed below the monolayer increases almost linearly with relative pressure to P/P0 = 0.8.Above this value, the amount adsorbed increases very rapidly with relative pressure. Hysteresis loops appear in the isotherms for all adsorption-desorption cycles. These loops are completely reversible. It is not possible to desorb the mercaptan monolayer from any of the adsorbents, even at elevated temperatures."

Jan 1, 1966