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By E. G. Bazeley

The paper reviews the scope, timing and financial impact of this significant project, which involves the supply and transportation of nearly 4 million tons per year of bituminous coal and lignite from sources in British Columbia. Alberta and Saskatchewan to Ontario Hydro's generating stations. The critical factors involved in the selection and utilization of these coals are discussed in relation to the three types of coal to be utilized initially. The paper then deals with each of the significant project elements to be undertaken by the various companies involved in the mining and movement of the coal, beginning with production at the mine through rail shipment to Thunder Bay, train-to-ship terminalling, shipment by lake vessel from there to the generating station, and finally blending the bituminous coal with United States coal prior to combustion. The review discusses the key features of the facilities involved in each case and the status and timing of the project elements , which are phased for the start of coal shipment by mid-1978. The paper concludes with some observations on the capability of the project to handle increased tonnage s and the challenges facing the movement in terms of quality , quantity and cost.

Jan 1, 1978

By Ruirui Wei, Yanhui Liu, Fangqing Yin, Meilong Hu

In China, Basic Oxygen Furnace (BOF) slag is traditionally used as an aggregate for civil engineering, for road engineering and fertilizer. In order to make full use of BOF slag, the experiments of BOF slag with high temperature roasting has been carried out and the phase transformation is studied. The BOF slag from Chongqing Iron & Steel is roasted in the electric muffle furnace at three different temperature. The influences of the high temperature roasting on change the phase composition of BOF slag was characterized by XRD. The results revealed that SFCA was produced at the high temperature in air atmosphere and melting temperature of slag was lowered. Therefore, if the BOF slag which treated by roasting was utilized in the sintering process, it is advantageous to improve the sintering strength and the formation of the liquid phase and reduce fuel consumption in the sintering production process.

Jan 1, 2015

By R. J. Leary

The natural gas-air burner described in this report was designed and constructed to meet the thermal requirements of a convective process for heating steel scrap. This process involved downward combustion of natural gas with air, blending the combustion products with diluent air, and then passing this tempered stream of gases downward through a porous bed of steel scrap contained in the furnace chamber. The scrap would be heated to a temperature limited by the adiabatic flame temperature of the gas stream in a period that depended on the rate at which heat was supplied per unit of bed cross section. The temperature of the gas stream would be limited to that beyond which an objectionable degree of oxidation would occur; for carbon steel this limit had been found to vary from 1,900° to 2,100° F. with the superficial velocity of the gas stream. The productivity of the process was dependent on the rate of heat input per unit of furnace cross section; for the 3-foot-diameter experimental furnace an input of 680,000 B.t.u. per hour was desired. The burner described was designed to meet these conditions of temperature and heat input. It provided for three streams of entering gases: (1) A primary air-fuel mixture too rich to be combustible, that is, above the upper flammable limit; (2) secondary air for combustion of the primary mixture; and (3) tertiary air, principally for cooling the combustion products to the temperatures desired for process operation. Downward combustion of the primary and secondary streams occurred in a flame stabilized on an annular port, while tertiary air flowed in an annular path surrounding the port and also through an axial channel whose wall formed the inner ring of the annular port. This burner performed beyond the designed heat-input rates while producing stable flames, which were adjusted readily to the temperatures desired. Gas-stream temperatures were easily controlled to within 15° F. of the desired value by simple manual adjustment of the flow valves.

Jan 1, 1959

By Tony Suckling

The commercially available finite element program Plaxis has a key benefit over other finite element analysis programs in that it has a relatively simple user interface to input and output data. This benefit though may also be it?s weakness in that anyone, regardless of their grounding in geotechnical engineering, may use the program and produce results for design. It is essential, as for all engineering design, that the models are checked by competent engineers. This paper describes the key recurring problems found by the authors when checking Plaxis models, such as the generation of the initial in-situ ground stresses and the modelling of groundwater. Interestingly, the authors have not encountered similar problems when checking finite element models produced using other programs and conclude that this may be due to the higher calibre of modeller needed to use these other programs. The geotechnical industry is in a situation at the moment where senior managers who may not have been trained in finite element modelling are relying on less experienced staff who have had some training in modelling, either at university or post graduation. The quality of this training is variable and all organisations running easy to use programs need to be aware of the potential risks and dangers. Management procedures and engineering checks that are essential to validate the results of these models are described, assuming that those in charge are not experienced modellers themselves. The model checking process by competent persons is absolutely essential and it is hoped that this paper will help those organisations that do not have such procedures as part of their own internal Quality Assurance or design validation system. The procedures described are valid for all finite element programs.

Jan 1, 2010

By Peter N. Gabby

A mineral purvey of 40,000 acres of the 42,213-acre Little Humboldt River Wilderness Study Area was conducted by the U.S. Bureau of Mines in 1985 at the request of the U.S. Bureau of Land Management. There are no identified mineral resources but anomalous gold, silver, mercury, and arsenic concentrations were found. The study area is located in Elko County, NV, in the Owyhee Upland geomorphic subprovince. It is underlain by mid- to late-Miocene-age rhyolite, basalt, tuff, vitric ash, and tuffaceous siltstone. On the south side and partly within the study area, a mining company recently (January 1986) located 125 contiguous claims over an area of hydrothermally-altered volcanic rocks that have anomalous surface concentrations of gold, mercury, arsenic, and silver. Anomalous gold-silver concentrations in altered rocks were encountered at several other widely scattered localities in the study area. These elevated metal concentrations and associated hydrothermal alteration indicate gold resources may be present in the study area. A 20-ft-thick bed of diatomaceous earth, which contains 60 to 85 percent diatoms, crops out 0.3 mi north of the study area. Elsewhere, three samples of altered volcanic tuff taken within the study area contain from 46 to 70 percent zeolite (clinoptilolite). The diatomaceous earth and zeolite sampled are not of sufficient quality to compete with materials presently being marketed. There has been no mineral production from the study area, but a caved adit, about 25 ft long, and six prospect pits were found.

Jan 1, 1987

By Albert L. Toenges

COAL mining technique progressed slowly until the advent of mechanized mining. The cutting machine was a forward step, but had only a limited effect upon improving the percentage of coal recovery. Previously, the physical fitness of the loaders and the total output of the miners fixed mine production. The miner was an independent contractor and supervision over his working place was superficial. Rising costs and the inroads of substitute fuels demanded increased output per man to lower the unit production cost. Therefore, the amount of coal loaded mechanically in underground bituminous mines has risen from 0.3 per-cent in 1923 to 7.4 in 1929, to 20.2 in 1937, and to 48.9 percent in 1943. When loading devices were introduced it became necessary to adapt them to existing systems of mining, or to alter the mining system to fit the machine. An increased amount of supervision was required as output depended upon proper operation of the machine rather than on the physical fitness of the individual.

Jan 1, 1946

Coeur d'Alene Mines is a precious metals producer which is dedi- cated to growth through it's exploration and acquisitions efforts. We foster and support these activities by providing our staff with long-term financial support, the encouragement to proceed with their projects and ideas, and a firm belief that we will be successful. Coeur's corporate headquarters are located in beautiful, historic Coeur d'Alene, Idaho. Our main mining operations are Rochester, locate near Lovelock, Nevada, Coeur Mine,located near Wallace, Idaho, and Thunder Mountain, located in central Idaho. Our Ken- sington Gold project is located about 45 miles north of Juneau in southeast Alaska. We have exploration offices located in Reno, Nevada, and Santiago, Chile. At this time, Coeurd'Alene Mines produces precious metals from mines located in the United States. Our Rochester open-pit opera- tion, which is 100 per cent owned and operated, is located in Nevada. Presently, this operation produces 5.5 to 6 million ounces of silver per year and 60-70,000 ounces of gold. We move 65,000 to 70,000 tons of rock per day of which about 23,000 tons is ore. The ore is crushed, stacked on permanent heaps and leached. The recovery is by Merrill-Crowe. Although the average grade is rela- tively low, 1.4 ounces per ton silver and 0.012 ounces per ton Au, the operation is very low cost. Our cost of production is less than $4.00 per silver equivalent ounce. Rochester is anunusual operation in that the crushed rock stacks without much compaction and the ores are easily leached. The final height on our heaps will be about 220', and overall recovery will be about 55 per cent of the silver and about 85 per cent of the gold. Reserves at Rochester are expanding and are now adequate for at least fifteen years of opera- Tion.

Jan 1, 1991

By R. E., Head

THE use of lime in flotation has become so general in recent years that its functions are familiar to plant operators. The conditions and phenomena described in this paper are of interest because they are directly associated with the use of lime as a reagent and the resulting formation of lime scale worth nearly $1 per pound for its gold content. It is not known to what extent lime scale is common in flotation plants where lime is used, but as several occurrences have been re- ported, its existence is not limited to one particular plant. In November, 1927, the author's attention was drawn to a lime scale that formed on the sides of Callow flotation cells in the Walker Mining Co. mill at Spring Gar- den, Cal. The scale was described as an accumulation of hard material that built up on the sides of both the rougher and cleaner cells and in some instances attained a thickness of 2 in. The lime scale builds up in the cleaner cell at the rate of about 1/10 in. per month, or slightly more than ?12 in. during six months' operation. The rate of growth in the rougher cells is slower, and about 3/s in. of scale forms in six months. Analyses' of typical lime scale samples are as follows:

Jan 1, 1928

By Harry Vivian

This paper deals principally with the retreating method of mining as applied in the Calumet & Hecla Consolidated Copper Co.'s deep Conglomerate mine, pointing cut some of the difficulties encountered in deep mining and describing the particular methods used at Calumet to carry on a large-scale operation at great depth with a minimum hazard factor. The circular is one of a series dealing with mining methods and costs which is being prepared for and published by the United States Bureau of Mines. ACKNOWLEDGMENTS Acknowledgment is due to those officials and operating heads of the Calumet & Hecla Cc. whose years of familiarity with the conditions developing at the Conglomerate mine as great depth was attained have enabled them to contribute valuable information to the subject of deep-mining problems.

Jan 1, 1931

By T Belligoi

Diamond cores and drill chips provide the only direct physical evidence for ore containing rocks. Early characterisation of cores and drill chips is important as it provides critical information for downstream processing. Traditional characterisation techniques include visual logging by a geologist or analytic and spectroscopic methods but they are time consuming and can miss some important textural or geomechanical features.The goal of this work is to evaluate the application of image analysis to iron ore cores and drill chips and to suggest improvements to existing core-scanning and chip monitoring systems. Two samples of massive ore differing by their mineralogy and texture, as well as two different batches of drill chips, have been imaged and analysed. Results are compared in function of the imaging system and the classification algorithms.As a conclusion, despite the necessity for more testing and improvements in calibration and lighting, it is obvious that image analysis technologies can bring a lot of useful information in the perspective of a geometallurgical mapping of the deposit.

Jul 11, 2011

By Stephen Mansfield, Saran Sankar

The Sentinel open pit copper mine, operated by First Quantum Minerals Ltd, is located in the North West province of Zambia. The Sentinel orebody is a sediment-hosted, structurally modified deposit in which mineralisation is contained in the phyllite formation, which occurs as a series of layered, continuous sheets having a northerly 20 to 30⁰ dip. The persistent nature of the geological structure can lead to the generation of large slabs when joints are relatively close together or very large blocks when joints are more widely spaced. With standard blasting methodologies, the challenging fragmentation most commonly occurs in the stemming zone and blast interfaces, reducing excavation rates and increasing the risk of crusher bridging events and reduced throughput. A generalised approach to increase powder factor would increase in drill and blast costs and would not be sufficient to target the specific cause of the challenging fragmentation. Implementing differential blast energy based on post blast requirements for different material type, such as ore and waste, and rock mass characteristics is not new in the mining industry. High-energy blasts for ore aim to produce finer materials, enhancing downstream processes such as crushing and grinding, while reducing power consumption and increasing throughput. Conversely, waste rock often requires less energy in order to deliver optimised fragmentation for loading and hauling efficiency. Identifying and applying optimum blast energy to specific material type and geological domains will not only ensure smoother and efficient operations throughout downstream processes, but will have a direct impact on overall profitability of the entire operation. This paper will describe the methods used to model and implement differential blasting across a range of material types in order to deliver the required blast outcomes for ore and waste and the impact on downstream processes and drill and blast unit cost.

Jan 21, 2025

By Mike Dry

Conventionally, lithium-bearing brines are processed via solar evaporation, chemical purification, and either electrolysis to lithium hydroxide or precipitation of lithium carbonate. Lithium-ion battery technology and electric vehicles are forecast to greatly increase the demand for lithium, but not all lithium-bearing brines are amenable to the conventional extraction process and new approaches are being developed. The chemistry associated with conventional lithium extraction is outlined and two new approaches are discussed.

By S. D. Hill

To help insure the continued viability of the minerals and materials sector of the U.S. economy, the Bureau of Mines is conducting research and disseminating technology that will result in more efficient minerals extraction. As part of this effort, a process is being investigated that involves an aqueous chlorine-oxygen leaching procedure to treat complex sulfide concentrates to produce ZnCl2. Subsequent fused-salt electrolysis of the ZnCI2 produces high-purity zinc metal. Previous reports described preliminary, small-scale research on the chlorine-oxygen leaching system and fused-salt electrolysis of ZnCl2. This report discusses the details of design, construction, and longterm, continuous operation of both monopolar and bipolar fused-salt cells. The effects of temperature, electrode gap, current density, electrolyte composition, and electrode configuration on current efficiency and energy consumption were determined for a ZnCl2-KC1-NaCl electrolyte system. Zinc metal was produced at the rate of about 50 lb/day in a monopolar cell which was operated continuously for 60 days with current efficiencies from 85.8 to 98.6 pct and an average power consumption of 2.1 kwhr/lb. Bipolar cells with several different electrode configurations were operated for 90 days. A current efficiency of about 70 pct and power consumption of about 1.7 kwhr/lb of zinc were achieved using a three-electrode-pair, bipolar assembly with a chlorine gas lift pump to circulate electrolyte.

Jan 1, 1981

By M. Turner-Jones, N. Steenekamp

"The Lonmin Base Metal Refinery treats converter matte from the Lonmin Smelter to produce nickel sulphate crystals, copper cathode as well as a concentrate containing the platinum group (PGM) metals. The original process employed a Sherritt design and utilizes atmospheric and pressure leaches for the dissolution of base metals. This paper describes the original flow sheet and the improvements made to enhance PGM recoveries, product quality and to increase capacity. Changes include the introduction of flash recycle cooling on the autoclave, batch leaches to improve the quality of the PGM concentrate and the implementation of solid-liquid separation with centrifuges. INTRODUCTIONThe Lonmin Base Metal Refinery (BMR) is about 100 km north-west of Johannesburg and treats converter matte from the Lonmin Smelter to produce nickel sulphate crystals, copper cathode and a concentrate containing the PGMs. The plant was commissioned in 1985 based on a Sherritt design to treat 12 tonnes converter matte per day. The original flow sheet consists of a milling circuit, an atmospheric leach and a pressure leach to produce a PGM concentrate which is despatched by helicopter to the Lonmin Platinum refinery in Brakpan, about 40 km east of Johannesburg. The liquor from the atmospheric leach is treated by crystallization to produce a nickel sulphate hexa-hydrate crystal. The leach liquor from the pressure leach is treated by a selenium removal step followed by electro-winning to produce copper cathode. The spent solution from the copper electro-winning is recycled to both the atmospheric and pressure leach steps to provide sulphuric acid for the leaching reactions.Modifications were made to the original circuit to increase the plant capacity, to improve the PGM recoveries and to improve the quality of the PGM concentrate. Capacity increases included all the unit operations, new mill, new first stage, additional autoclaves, additional nickel sulphate crystallizers, new copper electro-winning and new batch leach reactors for upgrading the PGM concentrate. The current circuit is described in this paper and not the detailed history of each plant change."

Jan 1, 2012

By S. J. Pearce

The need for a simple, very sensitive, and accurate method for the determination of benzene in blood and urine vas evident throughout a recent study of chronic benzene (C6H6) poisoning conducted cooperatively by the United States Bureau of Mines, The Barrett Company, and the producers of benzene. A combustion method which will be described in a later publication, and a previously described/ adaptation of Smyth's method were developed and used during that investigation. The adaptation of Smyth's method gave satisfactory results when dealing with exposure conditions that produced chronic poisoning in a comparatively few days, but it was time-consuming; and lacked the accuracy necessary for a study of the absorption, distribution, and fate of benzene in the body during exposure to threshold concentrations of benzene vapor in air. The combustion procedure was satisfactory from the standpoint of sensitivity but was cumbersome, intricate, time-consuming, and required the use of special and somewhat expensive Physical and chemical apparatus. Following the termination of this study of chronic poisoning, possibilities ides for developing better methods occurred, and these have been investigated by the Bureau of Mines with the aid of Relief Works Division personnel microcolorimetric method for the determination of benzene in air has been described recently.6/ The present report deals rich the adaptation of this new colorimetric method to the determination

Jan 1, 1936

By O. K. Mahabadi, A. Lisjak, B. S. A. Tatone, N. Vlachopoulos

"Numerical simulations are widely adopted in the design of several types of rock structures, including tunnels, caverns, rock cuts, and open pit and underground mines. In recent years, analyses based on the hybrid finite-discrete element method (FDEM) have been shown to provide a realistic representation of rock mass deformation and fracturing processes. To date, the FDEM approach has successfully yielded qualitative and quantitative results for several practical rock engineering applications, yet it has lacked the ability to consider the implementation of rock-reinforcement measures. Since rock reinforcement is often used in civil and mining applications to improve the strength and deformational behaviour of a rock mass, the ability to incorporate such features into FDEM analyses is essential to extend its applicability to a broader range of problems. The work presented in this paper represents an important first step towards developing a simulation tool that can be used for practical rock engineering applications, including the design of underground excavations and rock slopes.INTRODUCTIONRock support and reinforcement measures are often employed in civil and mining rock engineering projects in order to maintain or improve the strength and deformational behaviour of rock masses. The preferred type of reinforcement or support elements along with the preferred layout and timing of installation depend on the in-situ ground conditions, the nature of the rock mass and excavation method. Over the last two decades, numerical modelling has been increasingly used to design and attempt to optimize rock reinforcement and support systems. As such, most rock engineering-specific modelling software now offers various approaches for modelling different rock reinforcement and support elements."

Jan 1, 2015

A tough Conservation Act has been in force in Pennsylvania since January, 1964. Known as the Bituminous Coal Open Pit Mining Conservation Act, it is now under study by other coal producing states, and seems likely to serve as the blueprint for similar legislation elsewhere. It provides for the conservation and improvement of areas of land affected by open pit mining to decrease soil erosion, prevent pollution of rivers and streams, prevent combustion of unmined coal and generally improve the use and enjoyment of such lands. The cost of backfilling may go to as much as 40[c] or more per recovered ton and is cutting deeply into already reduced profit margins brought on by rising labor and equipment costs, static coal prices and less accessible coal. As a result, operators will be forced to seek greater efficiency.

Jan 7, 1965

By Bingliang Gao, Junli Xu, Michal Korenko, Jinzhao Guan, Liangxing Li, Zhongning Shi, Zhaowen Wang, Aimin Liu

Al-Si alloy, a precursor of solar grade silicon, was prepared by direct electrolysis in cryolite molten salt at 950 oC using high purity silica as material, liquid aluminum as the cathode and high purity graphite as the anode. The electrochemical behavior of Si(IV) ion was investigated using cyclic voltammetry method. The electrolysis products were characterized by XRD, SEM/EDS and ICP. The results indicate that the reduction process of Si(IV) on tungsten electrode is a two-step process and there is about 0.6 V gap between the two steps. The contents of boron and phosphorus in the aluminum-silicon alloy are 3 ppmw and 8 ppmw, which will make the directional solidification purification effectively and reduce the cost of preparation solar grade silicon from metallurgical grade silicon.

Jan 1, 2015

By Robert H. Raring

Viewed abstractly, a mill may be defined as a mineral processing facility located somewhere between the mine and the tailings storage area, Just how mining operations and the demands of tailings storage affect mill design is, the subject of this paper. At the outset, it will be readily acknowledged that no two installations can, or ever will be the same. At one extreme is the bucket line dredge where the distance between the ?mine? and the tailings area is measured in terms of tens of feet. At the other extreme, the large open pit copper mines are frequently spread across twenty, miles or so of countryside with the ore moving to the mill, as exemplified by the operations at Bingham Canyon, Ray, or Ruth - the "upstream" counterparts of Garfield, Hayden and McGill. In each of these cases, mill location was largely determined by requirements for tailings storage and/or water supply.

Jan 1, 1961

By Lloyd A. Morley

This report abstracts project work performed under USBM Grant GO155003 during the period 4 November 1975 to 3 November 1976. The research was funded, as a continuance of previous support from USBM Grants GO133077 and G0155003, to gain further knowledge in mine electrical system safety. Five reports have been separately produced, all under the grant title, "Coal Mine Electrical System Evaluation," and are as follows: 1. Volume I - Continuous Monitoring, 2. Volume II - Transient Analysis, 3. Volume III - Shielded Cables, 4. Volume IV - Computer Modeling, and 5. Volume V - Battery and Battery-charging Safety. Abstracts of these comprise the balance of this document with one exception. The task ?d-c offsett currents," does not fall under the scope of the other report volumes and, further, the material to be presented does not justify a separate report. Hence, this subject concludes the Executive Summary.

Jan 1, 1977