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By D. J. McCracken

During 1995, the estimated consumption of lithium minerals in the western world was 139 kt (153,000 st).This amounted to 18 kt (20,000 st) of lithium carbonate equivalent (LCE). Overall tonnage demand for lithium minerals increased by 10.8 kt (11,900 st) during 1995from 1994. From 1992 to 1995, overall tonnage demand has increased 62%, from 85.5 to 139 kt (94,240 st). There are four major producers of lithium minerals. Gwalia Consolidated in Western Australia is the largest producer of spodumene. It supplies high-grade spodumene concentrate, fine-spodumene concentrate, glass-grade spodumene and chemical-grade spodumene.Tantalum Mining (Tanco) of Manitoba, Canada, produces high-grade spodumene concentrate, fine-spodumene, concentrate and montebrasite. Bikita Minerals in Zimbabwe is the largest manufacturer of petalite. It supplies high-grade and container-glass petalite.

Jan 1, 1996

By T. Harrison

Surface coal mines in West Virginia are receiving stringent NPDES discharge limits for total recoverable selenium. With limits in the low parts-per-billion range, selection and implementation of proper sample collection and analytical methods are imperative for quality assurance and control and for consistency in results. Given the typical oxidized form of selenium in the water, the low limits and the large and variable flow rates from the watersheds, end-of-pipe treatment is difficult and cost-prohibitive to implement. Discharge locations in the remote and steep terrain exacerbate the problem. To evaluate options for end-of-pipe treatment at a Patriot Coal Corporation surface mining operation in West Virginia, CH2M HILL performed wastewater characterization for a range of key constituents and selenium species at three outfalls for selection and preliminary sizing of appropriate treatment processes. A preliminary evaluation of base and wet-weather flows was done to understand flow variability considerations for discharges. A conceptual evaluation of technologies to treat selenium to permitted levels was conducted in con-junction with order-of-magnitude life-cycle cost estimates.

Jan 1, 2010

By I. Y. Bausov, L. G. Stolarczyk, R. E. Pillmore, A. J. Hillard, J. T. Duncan

"Prevalence of lung disease in younger miners surprised industry regulators, congressional members, researchers and black lung clinic staff members. Mitigation researcher focused on low-coal mining in the Appalachian regions until Miners Colfax Medical Center (MCMC) Black Lung Clinic examinations discovered 25 of 72 Wyoming coal miners with lung disease. To reverse recent upward trend in lung disease, research programatic have been directed at reducing exposure to respirable “float” dust. This paper suggests broadening the scope of research to include boundary detection in efforts to improve outcomes. Beginning with a better understanding of biochemistry of anaerobic bacteria methylation processes precipitating sulfur and heavy metals into thin seam boundary layers. Expanding research and development objective to focused on minimization of bit-pick crushing cone volume and preventing mining thin boundary coal layers and out-of-seam dilution. Black lung clinical evaluations of miner will confirm outcomes directed towards reduced occupational disease and smoke stack emissions. INTRODUCTION Miner exposer to bit-tip crushing cone volume, fragmentation and auger movement generated respirable “float” dust and boiler emissions are related science-technology –engineering-mathematics (STEM) problems. Formidable but not intractable problems are driven by oxidation of upper flood plain elements in the periodic table and biochemical metabolic presses occurring in coal basin. Because of burial compaction, quartz and trace heavy metals (Fe2+, Mg2+) are concentrated in thin seam boundary layers. By not cutting through thin boundary coal layer and out-of-seam into hard quartz containing rock layers, miner lung disease and smoke stack emissions are minimized. Cutting bit-pick elastic wave hydrodynamic principle force vectors in the coal layer must be aligned to minimize respirable dust generation, constrained by fragmentation size. Dust abatement by water spray and machine design are effective; but for, failure to address cutting cone dust volume generation and its distribution along run-of-mine (ROM) transportation systems the boiler. Real-time precision thickness measurements by integrated cutting drum (icDrum) sensor, machine man-interdiction from a dust free control room, is a cost effective way to prevents respirable dust exposure. The recommended STEM research and demonstration initiative addresses issues raised by discoveries of increased rate of lung disease discovered in young miners and concerns over emissions from coal-fired electric generation stations (Global Warming). In-mine demonstrations must be validated by on-site MCMC mobile Black Lung Clinic data acquisition and analysis."

Jan 1, 2016

The role of ZnSO4 in activation of sphalerite (ZnS) and deactivation of lead-activated sphalerite has been investigated. Adsorption of metallic ions at the solid-solution interface, electrokinetic results for sphalerite under different chemical conditions, and thermodynamic calculations were used to elucidate the mechanisms involved. It is shown that flotation response of sphalerite in absence of activators is rather weak and that adsorption of ethyl xanthate on the mineral mainly electrostatic in nature. Zinc sulfate is found to activate the mineral but only in a narrow acidic pH range. This is attributed to the increase of zeta potential as well as the possible increase in amount of negatively charged bulk precipitated zinc xanthate. Lead ions activate sphalerite in a wide pH range and the lead activated mineral assumes a flotation behavior similar to that of galena (PbS). However, addition of ZnSO4 depresses the lead-activated sphalerite by replacing lead ions at the mineral/solution interface.

Jan 1, 1999

By M. Botz

Alacer Gold Corporation is constructing the Çöpler Gold Mine in eastern Turkey. Mining commenced in the fourth quarter of 2009 and gold production started in the fourth quarter of 2010. The mine is a 15,500 t/day oxide heap leach with three-stage crushing, agglomeration, carbon adsorption and electrowinning for final metal recovery. Leach solution copper levels are expected to be relatively low during the first two years of production, but will increase in later years due to higher copper content in the mined and processed ore. Over the mine life, approximately 40 Mt of ore will be placed on the leach pad, which will contain about 35,000 t of copper. Metallurgical testing indicates copper extraction will vary by ore type and, if controls are not implemented, may lead to copper levels exceeding 1,000 mg/L in pregnant solution. High copper levels in leach solution have the deleterious effect of increasing cyanide consumption and potentially overwhelming the ability of the carbon circuit to effectively adsorb the principal economic metals, which in this case are gold and silver. Using data obtained from laboratory leach column testwork, the heap leach facility was modeled using METSIM process simulation software to estimate the build-up of copper in leach solution over the life of the mine. Laboratory testwork was also performed to evaluate process conditions for treating a portion of pregnant leach solution via sulfide addition to precipitate saleable copper as copper sulfide (Cu2S).

Jan 1, 2011

By Donna L. Boreck

In an effort to increase recovery in thick and closely spaced coal seams, the Bureau of Hines, U.S. Department of the Interior, is studying the feasibility of introducing three mining methods-high-face longwall, multi-slice longwall, and longwall caving-in western coal operations. Geology plays a significant role in determining the success of such methods. Some of the factors that will affect development are as follows: (1) thickness and three-dimensional configuration of the seam, (2) cleats, joints, and fractures in the coal and roof rock, (3) roof composition and variability, and (4) coal quality and changes in quality within the seam. Through geologic mapping, the presence of many of these factors is predictable prior to development.

Jan 1, 1987

By Peter F. Howard

The lower Middle Cambrian phosphorite deposits of the Georgina Basin shown in Figure 1 were found in the period 1966-1968 by three companies, namely, International Minerals and Chemical Corporation, Continental Oil Corporation and Broken Hill South Limited. Of these deposits the significant ones are Duchess, Sherrin Creek, D Tree, Lady Annie, Lady Jane, and Wonarah which together aggregate several billion tons reserves of phosphate. Due to the economic factors of freight costs to the coast and softening of the world market price for rock phosphate, none of them is in production, nor is any in the development stage. This paper reviews the historical background to the discovery of these deposits and then deals principally with the discovery of non-outcropping phosphorites in the Barkly Tablelands of Northern Territory by the interpretation of gamma radiation logs of abandoned water bores.

Jan 1, 1971

By Joseph D. Drew

Oregon Resources Corp. (ORC) has developed and permitted a new mining operation that incorporates a process design that will allow the unique paleo-beach placer deposits of southwestern Oregon to be extracted efficiently and economically, creating the only domestically mined source of a unique foundry grade chromite and specialty de-veining sand for precision casting. The operation will also provide an additional domestic source of garnet and zircon. Engineering design has been guided by the variable geology and mineralogy of the paleo-beach placer deposits as well as the need for a dry tailing scheme that resolves a lack of water resources at the placer locations and at the same time eliminates the need for slurry settling ponds, typical of paleo-beach placer operations in North America.

Jan 1, 2010

By Xinghai Lei, Yuqi Shang, Guiming Li, Lu He

There are many factors affecting the stability of open-pit mine slopes, among which slopes with soft interlayers have become an important factor inducing deformation and instability due to their poor mechanical properties. In this paper, for the destabilization of a slope with soft interlayer under rainfall infiltration in an open-pit mine in Zhejiang Province of China during the rainy season, a sudden change of displacement at the monitoring point and the formation of a continuous plastic deformation of the slope are proposed as the criteria for slope destabilization through the establishment of a rainwater seepage-stress coupling model combined with the strength reduction method, and by using COMSOL Multiphysics finite element numerical simulation software to establish a three-dimensional numerical model based on the actual mining slope conditions. The safety principle is introduced through the strength reduction method to analyze the stability of the slope with soft interlayer under the coupling effect of seepage and stress. The safety coefficients of the slope with soft interlayer are calculated by using Numerical methods under the coupling effect of seepage and stress. The influence of rainfall intensity and duration on the stability or safety factor of the slope with soft interlayers was studied through analysis of stress, saturation, displacement, and pore pressure evolution. The mechanism of rainfall affecting slope stability was investigated, and the findings were validated using an engineering case study of a slope with a soft interlayer. The findings show that rainfall intensity is the main factor affecting slope stability in the open-pit mine slope with soft interlayer. The higher the rainfall intensity, the faster the shallow soil forms a saturation zone, whereas soft interlayers speed up the process and endanger slope stability. The slope prevention and control technology of the prestressed anchor cable (rod) framework was proposed based on the slope management construction conditions of the mine, and the effectiveness of the measure was verified through on-site industrial tests. The research findings provide a reference for preventing and controlling slope with soft interlayers in open-pit mines under similar conditions.

Feb 20, 2024

By Roger Malmström, H. Heden, Kjell Lidin

INTRODUCTION LKAB was formed at the turn of the century when the railways between the ore fields and harbors were built. The mines are situated north of the Arctic Circle in Sweden. Kiirunavaara is the largest mine, with a pro¬duction capacity of approximately 30 Mt/a. Malm¬berget has a capacity of about 12 Mt/ a. Both are under¬ground mines. Svappavaara, the only opencast mine currently in operation, has a capacity of about 4.5 Mt/a. The ore harbors are at Narvik for the Kiruna and Svappavaara mines and at Lulea for the Malmberget mine (see Fig. 1). Production in the form of finished products is shown in Fig. 2a, b, c, and d. Due to poor ore markets in re¬cent years, production and shipments have been cut back, but there was a positive swing in 1978. LKAB has been 96% state-owned since 1957. In addition to the iron mines in northern Sweden, LKAB has subsidiaries in central Sweden which produce sulfide ores, quartz sand, and uranium (Fig. 3). The mining methods employed are opencast bench stoping at Svappavaara and sublevel caving at Kiirunavaara and Malmberget. GEOLOGY The Kiirunavaara ore body is 4000 m long and av¬erages about 90 m wide, with variations in width from a few meters to around 150 m. The ore has been ex¬plored by deep drilling down to about 1000 m, but mag¬netic measurements indicate a depth of at least 1500 m. The Kiirunavaara ore is oriented in a north-northeasterly direction with a number of ores in the boundaries be¬tween the wall rock types. The ore in Kiirunavaara is mainly a fine-grained magnetite with a varying content of fine-grained apatite. The apatite content of the ore decreases with increasing depth. The other ores are all apatite-bearing and a couple are hematite ores (Fig. 4a, b). The ores are sedimentary, tilted, and tectonically de¬formed. They have a lateral dip of 0.87 to 1.2 rad (50 to 70°). The contacts between ore and wall rock are distinct and sharp, but both the hanging wall and the footwall are brecciated and impregnated with magnetite. The footwall of the Kiirunavaara ore consists of syenite porphyry with a low quartz content and rela¬tively good strength; the hanging wall consists of quartz porphyry. Both types are known as Kiruna porphyries. The ore at the boundary with the hanging wall is often rich in kaolin. There are a few veins of syenite porphyry running through the ore, which has a few major faults (Fig. 4c, d). There are two sharply delineated ore grades in Kiirunavaara: low phosphorus ore with less than 0.1 % phosphorus (about one-third of the ore) and high phos¬phorus ore with greater than 0.5% phosphorus. The iron content is 67% in the low phosphorus ore and 60% in the high phosphorus ore. These ore types are sold as different grades and so are kept separate during mining. MINING AT KIIRUNAVAARA The Kiirunavaara and Luossavaara ores were first mined using opencast bench stoping in 1902. When mining costs rose owing to higher waste removal, under¬ground methods were adopted. In the mid-1950s, the ores were still being mined on the surface at the same

Jan 1, 1982

By B. Arvidson

Computer-controlled machine sorting may, if properly applied, have a dramatic effect on overall economics of a mine operation. Radiometric and photometric sorters have been used for many years and new developments will be reported, such as a sorter for fine particles and a conductivity/magnetic sorter. Application examples with emphasis on precious metals will be given. Economics for some of the projects will be reviewed and discussed. Sorting underground is shown to be particularly attractive, but machine sorting would be profitable in most cases based on savings in transportation and milling/beneficiation costs only.

Jan 1, 1987

By Erich J. Jacob, Volker O. Meldner

INTRODUCTION Our company has made persistent efforts to utilize the very latest cost-saving technology in tunnel design and construction. However, we were relatively late in joining the clan of slurry shield tunnelers. The challenge came in 1973, when our company was low bidder on a major sewer tunnel in Hamburg, West Germany. The tunnel was to be driven under the harbor region through coarse and fine sands with up to 60 ft hydrostatic head of water. Outer diameter was 15 ft, and length was 2.9 miles. This contract appeared right to enter the new field of slurry face tunneling. We gathered a design-engineering team to develop the machine, called it "Hydroshield", and used it on the project. The good performance of the prototype machine encouraged us to improve and modify the equipment design. The very latest model is now in use on a subway tunnel in Antwerp, Belgium. This tunnel is 21 ft outer diameter and 2.4 miles in total length. In terms of excavated volume it is the world's largest slurry shield contract. While the drive is still in full swing, we are currently preparing for 3 further Hydroshield applications, with diameters ranging from 12 to 32 ft. This paper describes the Hydroshield's salient design features, operational characteristics, construction reliability and performance levels, as experienced in West Germany and Belgium.

Jan 1, 1979

By F. S. Knoll

Electrostatic separation is one of the most misunderstood physical processes used to beneficiate minerals. Nonetheless, millions of tons of titanium ores, iron ores and other minerals are processed every year economically, efficiently and safely. Over the past ten years major advances in electrostatic separation and its application have occurred. New processes include dewatering clay slurries, separating halite and sylvite, and shape separation of vermiculite and gangue minerals. Electrostatic separation techniques are based on one of two methods, electrophoresis or dieleccrophoresis -- processes involving charged and uncharged particles respectively. In some cases, the combination of these two techniques has proven quite useful. The purpose of this paper is to provide a basic understanding of the physical processes collectively called "electro- static separation" in order to enhance one's ability to define and consider new possibilities in mineral processing and other fields.

Jan 1, 1984

By A. W. Khair

This paper deals with the causes and mechanisms of pillar failure in a southern West Virginia coal mine. The conclusions are based on in-mine observations and analysis of mining methods, eyewitness account of the sequence of events, topographic and geologic conditions, and mechanical properties of mine roof, coal, and floor. The study indicated that massive pillar failure was caused by the collapse of the mine roof. The collapse of the mine roof was due to the combined effects of high lateral compressive stress and high extraction ratio causing excessive bending of the roof beyond its limit. It was assumed that the higher lateral compressive stress under such a shallow cover was probably due to the drastic change in the structural geology of the area and possible residual stresses. Eased on the analytical study it was concluded that the sudden release of elastic energy (shock) due to the rupture of the roof caused the squeezing of approximately eighty mine pillars.

Jan 1, 1983

By Raymond A. Bradbury

Martin County Coal Corporation's operations are located on Wolf Creek in Martin County in the eastern part of Kentucky. The mining complex was started in 1971 and has grown to a 2.273 Mt/a steam coal operation. All of the production goes to Duke Power Company's Belews Creek electric generating station in North Carolina. Production comes from four seams that are mined by deep and surface mining methods. Surface mining accounts for 55% of the production and the remainder comes from 2 underground mines. Continuous miners are used exclusively underground. The preparation plant was originally designed to take coal at the rate of 907 Mt/h but that has gradually been increased to 1134 Mt/h. Other cleaning equipment includes Daniels DMS vessels, Model 77 Deister tables, 355.4-mm R. & S. Hydro- cyclones, Krebs 254-m classifying cyclones, Daniels froth cells and in 1980, 3 Krebs 508-mm heavy media cyclones were added to recover some lost and misplaced material. CMI centrifugaldryers and a Hey1 & Patterson size 100 thermal dryer are also part of the coal preparation equipment.

Jan 1, 1981

By Shinzaburo Kato

In 1977 Kawasaki Steel Corporation (KSC) built No. 6 BF (Blast Furnace) with an inner volume of 4 500m3 as part of our program to produce 8.5 million tons of crude steel a year at Chiba Works. As the primary raw material to be used in No. 6 BF, we decided to use sintered ore, because we were confident in the obvious advantages of our technology developed by that time on sintering and BF operation using sintered ore. At Chiba Works, however, we had no space for the construction of a sinter plant, so we decided to build it abroad. Sintered ore is easily crushed and degradated. Producing sintered ore at a point far away from the blast furnace and transporting it across the ocean was the world's first attempt. To successfully realize it, we conducted a series of fundamental surveys and studies with special stress on the real aspects of degradation of sintered ore caused by long-distance transportation and handling and the ways and means to prevent the degradation. As a result, we decided to build a plant on the Mindanao of the Philippines.

Jan 1, 1982

By B. K. Parekh

Sludge obtained during production of magnesium (Mg) metal from electrolyzing of molten MgCl2 contains entrapped magnesium particles. The sludge material containing the magnesium particles is a friable, continuous matrix of frozen salt mixture which may also contain some oxides and impurities. A dry process was developed for recovery of magnesium metal from the sludge, utilizing minerals beneficiation unit operations. The steps included selective comminution, screening, attritioning and tabling. Recovery of the high grade (+90 percent) metal was in the 70 percent range. The process is being commercially used in the U.S. The novel process was also successfully applied to a magnesium-alloy for recovery of metal from the sludges.

Jan 1, 1995

By Stanislatv Pawlowski

New, large sulphur deposits were discovered in Poland in 1953, the result of investigations by the National Geological Institute. All deposits occur in a widespread Miocene evaporite unit in the Carpathian foredeep. The gypsum underlying impermeable Sarmatian clays was altered to limestone and native sulphur where penetrated by hydrocarbons and bacteria. All deposits occur in Miocene structural uplifts. The early determination of the genesis of the sulphur deposits and their occurrence in elevated blocks led to an exploration program that successfully located new deposits.

Jan 1, 1978

By K. Perry, B. Lusk, Q. Huang, R. Honaker

"Rock dust is applied in underground coal mines to prevent the propagation of coal dust explosions. The application is conducted either dry or wet. Both methods have advantages and disadvantages however the formation of caked rock dust particles is cited as a significant concern for wet applications. A study was conducted to evaluate the effect of modifying the rock dust particle surfaces to repel water and each other by the addition of oleic acid (OA) and sodium oleate (NaOL). At a NaOL dosage of 2 lbs/ton, a contact angle of 112o was measured indicating strong surface hydrophobicity and ability to repel water. FTIR studies indicated a chemisorption mechanism which is necessary for long term stability of the surface modification. The dispersion rate of the modified rock dust samples was elevated by the application of both OA and NaOL thereby indicating a significant reduction or elimination of the detrimental effect of caking. Tests in an explosion chamber showed a 79% reduction in the dust explosion potential relative to untreated rock test applied by the wet technique. INTRODUCTION Mine explosions have been a long-time threat to underground coal miners attracting significant attention to the accumulations of combustible dusts and gasses. In the presence of sufficient oxygen and heat, the accumulations of combustible dust and gass can lead to large-scale underground coal mine explosions [Harris et al., 2010]. To alleviate the problem, rock dust such as limestone can serve both as a thermal inhibitor and a heat sink to inert the coal dust explosibility thereby prohibiting the occurrence of dust explosions [Richmond et al., 1975; Amyotte et al., 1995; Dastidar et al., 1997; Man et al., 2009]. The dispersibility of the rock dust is an important characteristic that determines the degree of explosion prevention [Greenwald et al., 1938; Mozumdar et al., 1974; Amyotte et al., 1995]. Unfortunately, the environmental conditions of an underground mine has the potential to cause caking of the rock dust which reduces the dispersive characteristics needed. The dispersive property of rock dust can be enhanced by modification of the particle surface properties by the application of chemical additives [Greenwald et al., 1938; Mozumdar et al., 1974; Spence, 2004; Vogt, 2011; Doidge et al. 2014]. The major mechanism for rock dust caking is the adsorption of water which forms liquid bridges at the particle-particle contact points where saturated solutions of soluble powder ingredients are present. Changes in temperature or relative humidity result in solvent (water) evaporation and the formation of dry bridges [Rumpf, 1958; Specht, 2006]. One method to prevent caking is creating hydrophobic rock dust to repel water from the solid surface thereby preventing the formation of liquid and solid bridges."

Jan 1, 2015

By John C. Nichols

The Ouachita, Ozark-St. Francis, and Mark Twain National Forests are located within the Ozark and the Ouachita Mountains regions of southern Missouri, central and northern Arkansas, and eastern Oklahoma- an area generally referred to as the Ozark-Ouachita or Interior Highlands. These national forests share many similarities in geography, biotic resources, and areas of shared public, market, and user interests. The three national forests have joined together to evaluate the natural resources within the Highlands and to study the impacts of the forests on local and regional economies and on the people who use these national forests and their resources. Other federal, state, and local government agencies and universities have joined with the Forest Service in this project, broadening the assessment area beyond the national forest boundaries to include 107 counties in Arkansas, Missouri, and Oklahoma. The diverse, resource-related data for the as- sessment area address social, economic, terrestrial, and aquatic issues and conditions throughout the Highlands. The assessment report currently is being developed by the Forest Service and will include an accoMpanying CD-ROM. The Ozark-Ouachita Highlands assessment has provided a forum for minerals- and geology-related resources, industries, social significance, and potential to be profiled and discussed along with other critical assessment resources. The state geological agencies in Arkansas, Missouri, and Oklahoma were active contributors to this effort. Their reports and other key data bases developed and used for the minerals sections of the published assessment report will be available either as a supplemental CD-ROM or on the Internet. Updated information on the progress of the assessment report can be found at the Ouachita National Forest Website, at <http://www.fs.fed.us/oonf/ouachita.htm>. This will also include a matrix displaying the minerals in the assessment area, their occurrence by assessment-area counties, and a potential ranking, as well as information on interesting geologic features. The state and federal reports, resources, and data bases, have helped answer key questions concerning mineral resources and related issues in the Highlands:

Jan 1, 1999