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By Abbas H. Mirza

Arsenic and selenium are found in low quantities together with other metals in several nonferrous metallurgical process streams such as scrubber blowdown solution, acid plant wastewater, gas cleaning plant water, etc. Normally, the other metals in these streams are present as cations and can be precipitated by conventional lime treatment and sulfide polishing. However, arsenic and selenium are invariably present as anions, AsO33-and AsO43 in the case of arsenic and SeO32 and SeO42 for selenium. Conventional lime treatment removes most of the arsenic, but it does not remove selenium. The present paper reviews the processes and technologies developed to date on the removal of arsenic and selenium from metallurgical process streams.

Jan 1, 1996

By F. Chachula, A. Molinaro

"Sulphide mineral flotation operations continuously strive for a balance between mineralogy, mineral liberation, circuit conditions and reagent solutions to maximize the production rate and recovery of payable metals. The Taseko Gibraltar copper – molybdenum mill operations underwent an extensive project focusing on the fundamentals to identify the effects of process conditions and mineral liberation to improve the bulk circuit copper – molybdenum recovery efficiencies in the bulk flotation circuits. This discussion will provide process data that demonstrates; 1) fundamental relationship between mineral liberation to recovery and grade, 2) flotation circuit condition testing and optimization, 3) reagent combinations resulting in efficient/economical mineral recovery, and 4) the development of a xanthate free reagent solution. The data presented and discussed will also touch on flotation parameters including pH, retention time, kinetics and the effect on bulk circuit recovery performance.INTRODUCTION Taseko's is the owner (75%) and operator of the Gibraltar copper-molybdenum mine, located in south-central British Columbia, the second largest open pit copper mine in Canada and the largest employer in the Cariboo region. Taseko restarted Gibraltar in 2004. From 2006 until 2012, the company invested ~$700 million to expand and modernize the operation which was originally scheduled for demolition when the company acquired it in 1999. In the spring of 2011, construction commenced for Gibraltar Development Plan 3 (GDP3). GDP3 included the construction of a standalone 30,000 ton per day concentrator, built adjacent to the existing 55,000 ton per day facility. The new design capacity of Gibraltar was designed to be 85,000 tons per day. An integral part of the project was a new molybdenum recovery facility. In addition to the new concentrator, the mining fleet was upgraded with a new mining shovel, production drill and ten haul trucks (Taseko, May 2015). In May of 2015, the Company completed an updated mine plan for Gibraltar featuring a 50% decrease in strip ratio. This new mine plan was a result of a detailed, six-month engineering study and forms the basis of an updated NI 43-101 compliant reserve (Taseko Announces Improved Economics At Its Gibraltar Copper Mine, 2015). The new mine plan took into account lower milling costs as a result of the modernized processing facilities (Taseko, May 2015)."

Jan 1, 2018

By T. L. Heisler

The Cigar Lake project, located in northern Saskatchewan (Figure 1), is one of the world?s largest high grade uranium deposits, with reserves of 150 million kilograms of uranium in a deposit averaging 430 metres below the surface. The Cigar Lake project is being developed by Cigar Lake Mining Corporation (CLMC) which is owned by Cameco Corporation (48.75%), Cogema Canada (36.375%). Idemitsu Uranium Exploration Canada Ltd. (12.875%) and Korea Electric Power (2%). Mining the Cigar Lake orebody is presenting a very real challenge due to the high grade and the ground conditions in and around the orebody. Presently, an underground test of various mining methods is underway.

Jan 1, 1992

By J. W. Walkiewicz

Studies were conducted by the Bureau of Mines to develop a method for fabricating Sm-Co permanent magnets. This method consisted of arc-melting, crushing and grinding the alloy, alining and pressing the powder, and sintering the green compacts. Results indicated that the optimum composition was 36.7±0.3 weight-percent Sm and 63.3±0.3 weight-percent Co. This composition was obtained by blending together Sm2C07 and SmCo5. The maximum values exper¬imentally obtained were MHC = 27.4 kOe, BHc = 7,510 Oe, Br = 7,810 G, and (BH)max = 15.1 MGOe. The optimum sintering temperatures and grinding times for maximum MHc and (BH)max were determined. Lowering the grinding temperature from 0° C to -60° C resulted in a significant increase of magnetic properties.

Jan 1, 1973

By Gary Kahn

The knowledge of how and when your explosives go off can help you make intelligent decisions regarding future application of explosives thus removing some of the black magic associated with blasting. The net result will be intelligently set-up shots with timing, explosive charges, and placement more accurately done. Lower operational costs can be achieved when the correct combinations are applied.

Jan 1, 1989

By Y. Champoux, N. Atalla, R. Oddo, C. Lesage

"Percussion drills are the source of the most serious noise problems in mining activities, due to their extremely high noise levels(114-122 dB(A)) and widespread use(Bartholomae and Stein, 1988). Percussion drills will continue to be widely used to drill small diameter holes in hard rock because no other method seems to be economically avail-able to replace them (Boillat et al., 1993).Many studies (Danière, 1991; Hawkes etal., 1977a; Jensen and Visnapuu, 1972;Leblond et al., 1976; Milette, 1989) were con-ducted to determine the major noise sources of percussion drills. The exhaust air of pneumatic drills, the hammer, the bit in contact with the rock and the drill rod have been identified as the major noise sources. A muffer can be used to reduce the exhaust noise and the hammer can be enclosed. The bit noise is considered to be of concern only at the beginning of holes. When all the available methods are used to reduce the noise of a percussion drill, the drill rod vibrations become the dominant noise source (Hawkes and Burks, 1979). However, the noise levels generated by this source remain high and future efforts should concentrate on reducing its radiation.Works by Hawkes and Burks (1979) and Hawkes et al. (1977b) for the U.S. Bureau of Mines provide the most complete description on the noise and vibration of percussion drill rods.The longitudinal and bending waves are the two most important types of elastic waves generated in drill rods. Among these, only the longitudinal waves contribute to the drilling rate. The bending waves are caused by non-centralized impacts, drill rod curvature and non-uniform bit/rock interface. Drill rod noise is generated by Poisson’s ratio expansions and contractions of the rod as the longitudinal waves travel up and down it and by transverse rod motions induced by bending waves. The radiation efficiency is much higher for bending waves than for longitudinal waves. Most of the impact energy is transformed into longitudinal waves, as expected for axial impacts. The evaluation of the relative contribution of longitudinal and bending waves to noise generation poses a very difficult problem for experimental, analytical and numerical approaches. It is, however, an important issue because the relative contribution of these two waves will guide future noise reduction efforts. It seems that very little can be done to reduce the noise radiation of the axial waves without affecting the drilling rate. The main difficulty that analytical and numerical approach-es face, in the evaluation of the relative contribution of the two waves, is that there is no adequate theory for predicting the bending vibrations from the factors that cause them. The experimental approach has, thus, been limited to test fixtures that do not adequately represent the boundary conditions, as well as by measurements obtained under real operating conditions from which it is difficult to establish the relative contribution of the two types of waves. For example, Hawkes and Burks (1979) and Hawkes et al. (1977b) used a test fixture with free-free boundary conditions and made no clear link with measurement under real operating conditions. Rather, they have based their discussion on a simple model. Many authors assume that fexural waves are the main noise source on drill rods. However, measurements have been somewhat contradictory and researchers are still unable to state with certainty that this is indeed the case (Lednik et al., 1988)."

Jan 1, 1997

By Spencer S. Shannon

This chapter is concerned with the uses, geology, exploration, evaluation, preparation for markets, and future of 90thorium and 39yttrium, along with 14 rare-earth elements. The rare-earth metals or lanthanides were divided into three categories by Berzelius. The cerium subgroup is comprised of 57lanthanum, 58cerium, 59praseodymium, 60neodymium, and 62samarium. 61Promethium does not occur naturally. The terbium subgroup includes 63europium, 64gadolinium, and 65terbium. The remaining lanthanides are placed in the yttrium subgroup. Strictly speaking, yttrium is not a rare earth. Because the properties of yttrium resemble those of heavy rare earths, its name has been used as a designating adjective. The yttrium subgroup includes 66dysprosium, 67holmium, 68erbium, 69thulium, 70ytterbium, and 67lutetium. Rare-earth elements, especially those of the same subgroup, tend to occur together rather than in discrete minerals.

Jan 1, 1975

By J Channell, G Phillips

"The Chesney deposit, located 4 km south-east of Cobar consists of three copper-gold rich shoots that lie within a larger, copper dominant lode. A fourth gold rich shoot is located adjacent to the main deposit. The deposit exhibits a strong structural control on mineralisation, as brittle deformation during subvertical extension provided the requisite structural traps to precipitate sulfides from solution. It is postulated that the Great Chesney Fault acted as a fluid conduit, conveying fluids to the site of orebody formation. The continual supply of fluids resulted in cyclic brittle deformation when the fluid pressure exceeded the lithostatic pressure and the tensile strength of the Great Cobar Slate.Evidence supports the hypothesis that ore deposit formation was controlled by: a supply of mineralised fluids transported along the Great Chesney Faulta suitable location for the mineralised fluids to accumulate, accommodated by vertical extension and dilation in certain locationsthe creation of suitable structural traps to capture the sulfides. These traps formed as a result of fault-valve behaviour. Understanding the controls on mineralisation enables prediction of the location of other deposits with similar emplacement history, or extensions of current deposits.CITATION:Channell, J and Phillips, G, 2014. Understanding mineralisation controls – a case study of the Chesney deposit, in Proceedings Ninth International Mining Geology Conference 2014 , pp 301–312 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By Christopher Andreae

Years before iron and steel works were established at Sydney, several thriving although short-lived iron works operated in Nova Scotia. These furnaces reflected the general nineteenth-century North American experience with iron works. At the beginning of the century, small furnaces struggled to supply local needs. Charcoal was the principal fuel and water powered most furnace equipment. By the end of the century, a few huge primary iron and steel works dominated production for Nova Scotia and the rest of Canada. Two sites achieved prominence in the nineteenthcentury Nova Scotia iron industry: Londonderry and Ferrona (Fig. 1). Londonderry, the larger and longerlasting of the two sites, is today a small village on the south flank of the Cobequid Mountains, about 30 km west of Truro. Prior to the establishment of an iron works in 1849, no community existed. At the peak of operation in the 1880s, however, over 2600 people were located there. The second site, Ferrona, today is a mere crossroads on the map, about 10 km south of New Glasgow. Following the construction of a blast furnace there in 1892, a small village grew up around the furnace. But once the furnace was blown out in 1904, the population gradually drifted away.

Jan 1, 1999

By J. Burlin Johnson

In small-scale blasting experiments conducted in the Bureau of Mines laboratory, small charges were used to produce craters in blocks of concrete mortar. The results are compared with larger scale experiments of other research workers, and the comparison demonstrates the similarity of the results obtained and indicates that small-scale blasting should be a useful tool for predicting large-scale blasting effects. INTRODUCTION The purpose at this investigation was to conduct blasting experiments in mortar in the laboratory and then, by comparing the results with those from larger scale field blasts in rock to determine to what extent, if any, the laboratory results resemble those in the field. The work described herein was the initial phase of a project aimed at evaluating small-scale blasting as a tool for use in improving blasting techniques. It is evident from the stand-point of control and cost that small-scale blasting would be valuable in the study of rock fragmentation by blasting in mines and quarries, if the extrapolation is valid.

Jan 1, 1962

By Henry Ferguson

THIS paper is a preliminary statement, intended to present the more important results of the recent studies of the ore deposits of the Alleghany district in advance of the publication of the complete report, now in preparation. The Alleghany district (Fig. 1) has been a producer of gold since the early days of California gold mining. As in other California gold camps, placers yielded the bulk of the earlier production, but during the last 30 years lode deposits have been the only important source of output. The district differs from other California gold-quartz districts in that nearly all the production is from small shoots of high-grade ore. The mining camps of Alleghany and Forest are on the western flank of the Sierra Nevada range about 20 miles west of the crest. The gently sloping lava-covered plateau which controls the upland topography has been trenched by deep canyons of the westward flowing streams, which are cut to depths of as much as 2000 ft. below the crests of the ridges. The district is about 18 miles from Nevada City but the automobile road which connects the two places is 31 miles long. The senior writer first visited the district in 1913 and published a short description of the lode deposits.1 The increasing importance of the district made further study desirable. A detailed topographic map was therefore made by W. B. Upton, Jr., of the U. S. Geological Survey, in the spring of 1924, and the senior writer spent parts of the field seasons of 1924 and 1925 in the district. For the second field season the Geological Survey was fortunate in securing the services of R. W. Gannett, who had already done geologic work in the district for several of the mining companies. Owing to the death of Mr. Gannett in October, 1925, just before the close of his field work, the work of preparation of the entire report fell to Mr. Ferguson. He takes this opportunity of acknowledging how deeply he is indebted to Mr. Gannett for his excellent work in the field, and his realization of how greatly the completion of the report on the district has suffered from lack of Mr. Gannett's assistance in the office. In October, 1.928, after the completion of the first draft of the manuscript, Mr. Ferguson made a short visit to the district.

Jan 1, 1929

By Jorge Armstrong, Sean Warren, JOSEF BOURGEOIS

The application of statistical analysis software programs has proven useful for the investigation of rockfall runout distance along a designed slope. Rockfall modeling programs are continually being upgraded with more sophisticated analysis tools, such as the use of the rigid body versus lump mass models. Engineers at mine sites utilizing the software may have varied experience related to these models, their associated input parameters, and how to interpret the generated results. To address this concern, researchers at the Spokane Mining Research Division (SMRD) of the US National Institute for Occupational Safety and Health (NIOSH) investigated the influence of slope height, slope angle, slope material, and rock size for both rigid body and lump mass models in a 2-D statistical analysis program. Based on a literature search and industry input, specific ranges common to that of an open pit mining environment were chosen for each of the input parameters to determine 90% rock runout distance as well as their sensitivity to change. Data collected from this numerical analysis and simulation will be compared to empirical rockfall data gathered through the duration of the Highwall Safety project conducted by NIOSH from 2022–2026.

Jun 18, 2023

By Verya Nasri, Agustin Rey

Once completed, the Montreal Réseau Express Métropolitain (REM) will be the fourth largest automated transportation system in the world. The REM represents construction costs of approximately 7.0 billion Canadian dollars. The project consists of 67 km of twin tracks over four branches connected to downtown Montreal. The project includes 26 stations with 3 underground stations in downtown Montreal. One of the underground stations was built using the NATM method with thin permanent shotcrete initial and final liners separated by a sprayed on waterproofing membrane. The 2 other underground stations were built with the cut and cover approach including one using permanent secant pile wall with permanent walers and struts as the support of excavation and the final perimeter wall of the station. The project also includes the rehabilitation and enlargement of the Mont Royal Tunnel. This 100-year-old double track tunnel is about 5 km long. The REM also consists of 3.6 km new TBM tunnel connecting downtown to the Montreal International Airport through saturated soft ground and karstic rock. By the time of RETC, the construction of REM underground structures will be completed. This paper presents the design and construction aspects of the underground structures of this mega project.

Jun 13, 2023

By Oscar Damiani

El presente texto señala la distribución general de las brechas encontradas en el depósito de Toquepala, especialmente la distribución de la brecha de colapso, a través de ciertas orientaciones. Esta distribución incompatible con el origen diatrémico propuesto anteriormente, sugiere la posibilidad de establecer preliminarmente que el depósito ha sido originado por el fenómeno conocido como «magmatic stopping» emplazado en un área de debilitamiento ocasionado por la intersección de varias fallas pre - existentes, generando de este modo el «breccia pipe».

Sep 1, 1968

By Frank Ruskey

This report describes a computer program devised by the Bureau of Mines to model coal-mining situations where one or more panels encounter oil or gas wells. The program seeks in several hundred trials to evade the wells if possible or to minimize their influence by shifting or skewing the mine plan and/or adjusting the centerline dimensions of the entryways. Upon completion of computations, the program sorts the hundreds of models which have been tested, and lists the 10 best with their associated parameters. It also draws a mine plan of the best configuration, showing the entryways and crosscuts along with the "lost" coal remaining in the barrier pillars surrounding the various wells.

Jan 1, 1972

By C. Matthews, A. Vo

"Australia is one of the world’s leading exporters of bulk commodities and the extensive use of sampling equipment is key to the successful management of each mining operation. At the process plant, without a full understanding of the feed, product and tails, it is impossible to fully optimise the performance of the plant, such that the metallurgical balance is often open to error. At the port, a statistically correct, bias free and compliant sampling system is crucial to ensuring exported minerals are reflective of their true value and to avoid penalties. Over the last decade, as a result of the iron ore boom, there has been high demand for reliable, representative and standard compliant solids sample systems in Australia. This paper reviews several solids sampling applications at Australian mine sites, the challenges and experience gained and how the implementation of reliable representative sampling systems has provided better understanding of plant process performance, improved plant control and overall benefits to the operations.INTRODUCTION Mining is the primary contributor to the Australian economy with Australia ranking in the top 4 in economic resources for 21 primary industrial minerals in 2016 (Britt, et al., 2017). Australia is one of the world leaders in the export of the majority of its commodities including gold, copper and iron ore (Britt, et al., 2017). Therefore, a suitable and standard compliant sampling system is essential for evaluating plant performance and content verification. At the mine and at the port, the larger iron ore miners in Australia have developed stockpile models to predict the grade of their ore down to individual blocks of the stockpile. This allows the miner to create the right blend of material for sale to their customers and ensures they are not underselling their product or at risk of penalties for impurities or low grade. As an example, the average difference between the benchmark 62% Fe and low grade 58% Fe fines at the time of this report averaged US $30/tonne according to the Metal Bulletin Iron Ore Index. At a shipload of 180kt this would be a variation of US $5.4M. Whilst this is an extreme example, it highlights the economic importance of producing the correct grade product and a recognised representative sample of said product."

Jan 1, 2019

By L. J. Cunningham

Introduction The property of Rouyn Merger Gold Mines, Limited, is in Rouyn and Joannès townships, Western Quebec, seven miles east of the town of Rouyn. Traversing it is the east-west trending Cadillac-Bouzan fault. Diamond drilling in 1944 and 1945 along a shear zone south of the fault indicated an ore deposit lying at the contact between sedimentary and volcanic rocks and dipping approximately 60° to the northwest. In the summer of 1945 it was decided to sink a shaft to investigate the indicated ore zone. In the immediate vicinity of the deposit, bed-rock is overlain by clay beds, in some places as much as 70 feet thick. Consequently, possible shaft sites were limited to those locations where overburden would not be excessive. The most favourable site was about 125 feet to the south of the ore zone as projected vertically from bed-rock to the surface. Accordingly, it was decided to sink the shaft at this point, with an inclination of 60° N. W., paralleling the dip of the ore zone.

Jan 1, 1948

By A. Romero

"Most underground mines require heating or cooling systems to meet health and safety standards in the working areas. In regions where daily or seasonal fluctuations of environmental conditions exist, these systems tend to be over-sized and operate at low average load factors, which increase both investment and operating costs. One possible approach to reduce the temperature variations of the fresh air supplied to the mine, and so reducing the investment in large heating or cooling systems, is to use rock as a thermal regenerator or thermal storage system. Packed rock beds act as thermal inertial units, damping the atmospheric temperature oscillations to provide a more constant fresh air temperature. However, although regenerators exist in some mines, and packed bed rocks have been studied in detail in solar thermal power applications, there is a lack of tools to design new and sufficiently large storage systems of this kind. This work fills the existing gap by presenting a methodology to design and evaluate the impact on the ventilation systems of these regenerators. The method is validated using existing rock bed systems found in the literature and illustrates possible designs for small and large size regenerators in both hot and cold climates.1 INTRODUCTION “ It is quite amazing how often answers to extremely complicated problems can be obtained in this way, by using greatly simplified models of the real situation for the purpose of calculation.” Whiller, A. in private communication to J. S. Stachulak (1989). Motivation Most underground mines located in regions with extreme climatic conditions require the thermal pre-treatment of the fresh ventilation airflows, whether for heating or cooling. Heating commonly is needed in sites with sub-zero temperatures and is usually effected by direct or indirect burning of natural gas or propane. Alternatively, cooling is required in areas with hot temperatures, or in mines with high underground thermal loads where the fresh air at ambient temperature cannot provide enough refrigeration. Thus, when the ambient air conditions cannot provide by itself enough thermal power to ensure safe underground working conditions, a heating or cooling plant is required, which involves a considerable equipment and operation cost."

Jan 1, 2019

By Roy F. Abernethy

This publication by the Federal Bureau of Mines contains the free-swelling indexes for 2,812 samples of coal received from January 26, 1948, to July 15, 1957, and the Hardgrove grindability indexes for 2,339 samples of coal received from June 23, 1947, to July 15, 1957. These data consist of the origin of the sample, bed name, and analysis. Summaries show the high, low, and average values for each bed. The free-swelling index is a relative measure of the caking properties of a coal when burned on a grate, and the Hardgrove grindability index is used to estimate the relative ease of grinding coals. Development and standardization of these test procedures were at a much later date than those for the more familiar tests, such as proximate and ultimate analyses and calorific value determinations. The newer tests are valuable in supplying supplemental information, particularly for assisting in evaluating coals used in certain types of combustion processes.4/ Data from such tests are important to designers of burning equipment, operating engineers, and purchasing agents. Data from these newer tests are scarce and scattered through a number of publications. Special projects were started to determine the free-swelling and grindability indexes, in addition to the regular analyses on the tipple samples collected by Bureau engineers. Since the start of these special projects, all the coal fields of commercial importance have been adequately covered in the sampling program.

Jan 1, 1961

By G. ALBORNOZ, S. Utili, A. AGOSTI, C. VALDERRAMA, R. PELL, N. Morales

The steepness of the slopes of an open pit mine has a substantial influence on the financial return of the mine. The paper proposes a novel design methodology where overall steeper pitwalls are employed without compromising the safety of the mine. In current design practice pitwall profiles are often planar in crosssection and the profile in between ramps especially tend to be planar and defined by a constant inter-ramp angle. Sometimes rock layers exhibiting different strengths require the inclination of the profile to vary with depth, but the inclination across each layer is usually constant. Here instead, a new geotechnical software, OptimalSlope, is employed to determine optimal pitwall profiles of depth varying inclination. OptimalSlope seeks the solution of a mathematical optimization problem where the overall steepness of the pitwall, from crest to toe, is maximized for an assigned lithology, geotechnical properties and Factor of Safety (FoS). Bench geometries (bench height, face inclination, minimum berm width) are imposed in the optimization as constraints which bind the maximum local inclination of the sought optimal profile together with any other constraints such as geological discontinuities that may influence slope failure. The obtained optimal profiles are always steeper than their planar counterparts (i.e. the planar profiles exhibiting the same FoS) up to 8 degrees depending on rock type and severity of constraints on local inclinations. The design of a copper mine is first carried out employing planar pitwalls, secondly adopting the optimal pitwall profiles determined by OptimalSlope. The adoption of optimal slope profiles leads to a 34% higher net present value and reductions of carbon footprint and energy consumption of 0.17 Mt CO2 eq and 82.5 million MJ respectively due to a 15% reduction of rockwaste volume.

Mar 2, 2022