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By E. A. Devuyst, G. Robbins

A unique process for removing cyanide and base metal complexes from industrial waste streams was patented by G.J. Borberly et al. (1984). The process uses SO2 (liquid or gas, or solutions of sulfite salts, or from burning elemental sulfur), plus air that is dispersed in the effluent using a well agitated vessel. Acid produced in the oxidation reactions is neutralized with lime at a controlled pH generally in the range 7 to 10. The reaction requires the presence of soluble copper as a catalyst which can be supplemented by copper sulfate if necessary. The process can be applied to the detoxification of gold and silver mining waste streams, such as carbon-in-pulp (CIP) tailing pulps, barren solution bleeds, pond waters and heap leach rinse solutions and also to plating shops wastewaters. The SO.jAir process has substantial advantages over two of the main alternative methods of cyanide destruction, namely alkaline chlorination and hydrogen peroxide. Alkaline chlorination is highly penalized in terms of reagent consumption. Chlorine is a strong oxidant reacting with species other than cyanide present in the effluent such as thiocyanate and sulfides. Furthermore alkaline chlorination is an incomplete detoxification process. Iron cyanide is not removed and the potential for harmful by-products species exist. Consequently final effluents may be subject to additional treatment in order to comply with regulatory demands.

Jan 1, 1991

By E. A. Devuyst

A unique process for removing cyanide and base metal complexes from industrial waste streams was patented by Borberly et al. (1984). The process uses S0, (liquid or gas, or solutions of sulfite salts, or from burning elemental sulfur), plus air that is dispersed in the effluent using a well agitated vessel. Acid produced in the oxidation reactions is neutralized with lime at a controlled pH generally in the range 7 to 10. The reaction requires the presence of soluble copper as a catalyst that can be supplemented by copper sulfate if necessary. The process can be applied to the detoxification of gold and silver mining waste streams, such as carbon-in-pulp (CIP) tailing pulps, barren solution bleeds, pond waters and heap leach rinse solutions and also to plating shops waste waters. The S02/Air process has substantial advantages over two of the main alternative methods of cyanide destruction, namely alkaline chlorination and hydrogen peroxide. Alkaline chlorination is highly penalized in terms of reagent consumption. Chlorine is a strong oxidant reacting with species other than cyanide present in the effluent such as thiocyanate and sulfides. Furthermore, alkaline chlorination is an incomplete detoxification process. Iron cyanide is not removed and the potential for harmful byproducts species exist. Consequently, final effluents may be subject to additional treatment in order to comply with regulatory demands.

Jan 1, 1991

By Paul M. Keyser

Flotation columns continue to offer improved metallurgical and economic advantages over other flotation methods. Pilot testing at Ozark-Mahoning Co. in Rosiclare, IL led to installation of one 2.3-m-diam (7.5-ft-diam) column for zinc roughing and one 1.1-m-diam (3.5-ft-diam) column for zinc cleaning. This circuit replaced one stage of mechanical roughing-scavenging followed by two stages of cleaner flotation. General Column flotation continues to make inroads into applications traditionally dominated by mechanical flotation cells. For example, columns are becoming more visible as rougher flotation devices. At Royal Mountain King Mine in California, two 2.9-m-diam (9.5-ftdiam) columns are used for rougher flotation of carbon from a gold ore (Orlich et al., 1992). In addition, work performed at BRGM in France demonstrated the superiority of column flotation over mechanical flotation with respect to design of new plants (Morizot et al., 1991). The primary reasons for this acceptance of columns are a general improvement in design, scale-up and operation, as well as improvements in sparger design and performance. With these advances, the full benefits of column flotation can be realized. The benefits of properly designed, aerated and operated flotation columns include lower capital costs, reduced operating costs, fewer processing stages and improved metallurgical performance.

Jan 1, 1993

By John R. Marks

The first 0.7 m3 (1 cu yd) diesel load- haul-dump vehicle (LHD) arrived at the Homestake Gold Mine in Lead, SD in I969 to muck a ventilation drift. Others soon followed. Mechanization has subsequently changed stoping methods, manpower requirements, ventilation practice, the definition of minable reserves, and it has impacted safety and health. These have all had a direct bearing on the economics of producing gold ore from deep underground. Mechanized mining Before mechanization, production quotas at Homestake were met by several open cut-and-fill (OCF) mining methods. OCF mining relied on jackleg and wagon drilling, electric and compressed air slushing and cribbed raises brought up through the fill. Even square- set stoping was used until about eight years ago. The mine became 100% mechanized in 1988. The two current stoping methods are mechanized cut-and-fill (MCF) and vertical crater retreat (VCR). In 1992, MCF accounted for 54’S, VCR for 44% and development/uphole for 2% of the 1.4 Mt (1.55 million st) of underground ore produced. These methods are typically ramp- based and use diesel-powered LHDs, trucks, pneumatic drill jumbos and utility vehicles. Electric LHDs and rubber-tired compressed air muckers have also been used in VCR scrams. Pfarr (1991) and Mitchell (1980) provide good overviews of current production methods.

Jan 1, 1993

By Pierre M. Matheron

TRANSMANCHE-LINK is responsible for designing, developing and implementing the project for a fixed link under the English Channel, comprising two running tunnels of diameter 7.6 metres and a service tunnel of diameter 4.8 metres. The three tunnels will all be 50 km long, with 37 km bored through chalk marl at a depth of 40 metres under the sea bed. The tunnels will be driven from both sides of the channel from intermediate addits above the coastline on either side with a 55 m access shaft at Sangatte in France and two "descenderies" or inclined tunnels addits and a shaft at Shakespeare Cliff on the English side. A total of eleven tunnel boring machines will drive the 150 km of tunnels. The major part of the tunnel linings will be built of precast reinforced concrete segments, and two plants have been specially built to produce the necessary 725,000 segments. Seven million cubic metres will be evacuated on wagons along the tunnels and then lifted by belt conveyor on the English side, and by hydraulic mucking from the bottom on the French side. Preliminary work started early in 1987 with manufacture of the first boring machines, construction of five precasting plants, boring of the Sangatte shaft in preparation of the Shakespeare Cliff entrances. The principal project dates are :

Jan 1, 1987

By Vinton A. Garbesi

The construction involved in the Washington Metropolitan Area Transit Authority (WMATA), Contract No. lK0011 (K-1), encompassed some 2,621 meters of single track parallel tube rapid transit tunnels, 335 meters of cut-cover subway station and appurtenant ventilation structures at each end, and a fan shaft at approximately the mid point of the tunnels. The construction contract was awarded June 7, 1974 to a Joint Venture consisting of Intercounty Construction Corporation, Hyattsville, Maryland, and S $ M Constructors, Inc., Solon, Ohio. The former being responsible for performing the cut and cover construction, and the latter being charged with constructing the running tunnels and fan shaft at their mid point. (See Fig. 1) The problems of mining and supporting, the 183 meters of twin tunnels just east of Court House Square Station, by unique mixed face and soft ground mining methods is the main subject of this report, although a general review of the tunnels in their entirety, as well as the geology encountered in the excavations, is presented to give a better overall setting for the problems encountered. GEOLOGIC SETTING The tunnels for the K-1 contract are located in three general types of material; the first being fractured and metamorphosed ignious rock (quartz-hornblende-biotite gneiss), the transition zone between weathered and competent rock, and in ground consisting of the weathered

Jan 1, 1979

By R. J. Reuss

Mina Maria is a high-grade, underground copper mine located in the Cananea district of Sonora, Mexico. The ore body is a massive sulfide breccia located in mountainous terrain. A major highway and an electric transmission line pass directly over the near-surface ore body. The mine is operated by Minera Maria SA de CV, a joint venture company that is 51 % owned by Empresas Frisco SA de CV and 49% by Cominco Resources International Ltd. Empresas Frisco is the operating partner. Production began in October 1990. The mining method used is undercut and fill. A continuous miner and a single-boom, hydraulic jumbo mine the ore. Backfill is a weakly cemented sand-gravel mixture that is pneumatically placed. The ore is treated by conventional crushing, milling and flotation. The Maria deposit is located about 40 km (25 miles) south of the Sonora-Arizona border and 11km (7 miles) northwest the city of Cananea and the Cananea Mine. The mine portal, at an elevation of 1780m (5840 ft), is on the east side of an important drainage divide. The mill site is situated about 800 m (2625 ft) northwest of the mine on the northwest side of the drainage divide where the drainage is more favorable. Its elevation is 1860 m (6100 ft) (Fig. 1).

Jan 1, 1992

By Thomas C. Anderson, Terry Weiss

The Mount Gunnison No. 1 Mine of the West Elk Coal Company (wholly owned subsidiary of ARCO Coal) had secured contracts to provide low sulfur, high Btu steam coal to various utility companies. This called for the development of the B-Seam at the Mount Gunnison Mine located some 400 feet below the operating F-Seam workings being mined with conventional room and pillar techniques. The B-Seam, to meet production goals, will be mined by a new 600-foot longwall machine making a 13-foot high cut. American Mine Services was awarded a competitively bid contract to drive two 2000-foot, 13-foot by 16-foot slopes at -15 percent, sink a 16-foot diameter ventilation shaft 400 feet between the F- and B-Seams, install a 60-inch conveyor in one of the slopes, remove 7000 feet of existing conveyor and rehabilitate 7000 feet in two entries to accommodate the placement of the longwall machinery. The slope portals were located 7000 feet in by the surface portal. Unique to the project was the placement of work shops and other infrastructure 7000 feet underground with an entry height of 6 feet. The $7 million contract was completed in less than one year using a mix of permissible (Schedule 31) and standard (Schedule 24) LHD equipment, all pneumatic jumbos and shaft sinking gear.

Jan 1, 1993

By James S. Goff, Stephen J. Navin, Wesley W. Moulton

The White River Shale Oil Corporation (WRSOC) is developing a prototype oil shale facility on Federal Lease Tracts Ua and Ub located in northeastern Utah. This paper covers the successful driving of 1,525 m (5,000 ft) of dogleg downgrade decline with a 70-ton Paurat Roadheader mining machine and a conveyor muck-handling system. Ground support is with rock bolt and shotcrete; welded wire mesh is optional. The Upper Decline of 3.89 m by 8.69 m (12.75 ft by 28.5 ft) was mined through the Uinta Formation sandstones and shales in 210 days. The sandstones have a compressive strength in the 48 MPa (7,000 psi) range with a few bands of shale up to 137.8 MPa (20,000 psi). Green River Formation dolomitic marlstone with some sandstone lenses was mined in the Lower Decline 3.89 m by 5.64 m (12.75 ft by 18.5 ft) in 175 days. The Green River marlstones are tough massive formations ranging up to 206.8 MPa (30,000 psi). Roadheaders for use on steep slopes must be modified to accommodate the particular problems associated with mining downdip. The paper concentrates on the application of Roadheaders to steep slopes and the problems of mining tough materials such as marlstone. The paper also shows the advantage of using the method of excavation on long drives.

Jan 1, 1985

By Nick Barton, Harald Hansteen

The deformations resulting from excavation of very large openings are compared using two-dimensional F.E. continuum analyses and discontinuous physical models (20,000 discrete blocks). Both the joint orientations and the model horizontal stress levels were varied. Some models were dynamically loaded to simulate earthquakes (0.2-0.7 g). Model deformations were recorded using photogrammetry. The changes in deformation when increasing the simulated spans from 20 m to 50 m were of particular interest. High horizontal stress caused surface heave when joint orientations were favourable for arch stability. Joint orientations also determined whether the pillars between parallel openings were in a state of compression or tension. INTRODUCTION The engineering performance of large rock caverns has traditionally been learned from mining and hydro power projects, where the depth below surface is often many times greater than the span of the openings. Deformations measured in the walls and roofs of hydro power caverns generally range from about 5-50 mm, though there is a documented case where a wall moved in 126 mm (1), and another where the arch moved down 147 mm (2). The chief objectives of the present studies of large near-surface openings were threefold: (i) to provide deformation data to compare with monitored data from planned engineering projects involving large span near-surface excavations, e.g. underground sports complexes, civil defense shelters, nuclear power stations,

Jan 1, 1979

By W. Belobraidich

Kennecott's Ray mine is located about 145 km (90 miles) north of Tucson in the Mineral Creek mining district of central Arizona. Mining in the district started in the late 1800's. The Ray mine itself was first mined by under- ground methods in 1911 and was changed to an open-pit operation in 1952. Mineralization is complex and includes sulfide, silicate, and native copper mineralization, as well as minor amounts of molybdenite. Sulfide ore, mined at Ray, is shipped by rail to Kennecott's concentrator and smelter at Hayden, 32 km (20 miies) away. Silicate ore, mostly chrysocolla, is processed near the mine in a vat leaching-electro- winning plant. The mine consists of two sulfide areas: (1) the West pit and the Central pit (the original Pearl Handle pit) and (2) a silicate area on the northeast perimeter of the Central pit. The pit now is over 304 m (1000 ft) deep and approximately 3048 m (10,000 ft) long. Roads within the ultimate pit are limited to a grade of 10%, while those outside the pit are limited to 8%. The mining equipment consists of 40 Wabco 1094 (120-st) haulage trucks [ranging from 109 to 227 t (120 to 250 st)], 12 electric shovels [ranging from 6 to 23 m (7 to 25 yd)], and 3 11-m (12-yd) Dart production loaders.

Jan 1, 1979

By D. P. Gold

Major sources and reserves of Cb/Nb, Ta, REE, Y, Sc, Zr, Hf, Cu, apatite and vermiculite may be concentrated in primary and secondary minerals associated with different stages and depths of emplacement in carbonatite complexes and kindred alkalic intrusive rocks. Exploration targets include: apatite and pyrochlore (Nb) in the plutonic and hypabyssal core and ring-dikes: bastnaesite (REE), strontianite, barite and fluorite in hydrothermal veins and cone-sheets (subvolcanic setting): thortveitite (Sc,Y) and vermiculite in metasomatized aureoles (fenites): high grade eluvial deposits of apatite and pyrochlore, and secondary REE, Nb, Ti. and V-minerals in supergene and weathered zones.

Jan 1, 1991

By J. A. Organiscak

This paper describes the research con-ducted on bit wear and respirable dust generation conducted by the US Bureau of Mines (USBM) and West Virginia University (WVU), a member of the Generic Technology Center on Respirable Dust. The USBM investigated wear, energy and dust characteristics of various conical bit designs when cutting rock. WVU studied the functional relationships between wear, cutting force, energy, and dust of one conical bit type when cutting coal. The objective of the USBM study was to identify qualitative bit selection guidelines for cut-ting rock; WVU's research objective was to determine optimum bit replacement guidelines. These research studies both found that bit geometry (a function of bit design and wear) influences energy consumption and dust generation. Bit selection and replacement recommendations are given.

Jan 1, 1995

By Dipl. -Ing. Mertens

Gentlemen: I am pleased and regard it as a priviledge to give you a report on rapid roadheading with heading machines in the coal mining industry of Western Germany. Importance of Heading Operations in the West German Coal Mining Industry Every year about 770 km of headings are driven In the seams of the West German coal mines, most of them gate roads, the rest rise headings, to open new faces. In thick seams the heading operations are carried out entirely in the coal, in thin seams the country rock has to be ripped. The total length of 770 km corresponds to a rock volume of roughly 9.5 million m3; this figure underlines the importance of the heading operations in the coal mining industry of our country.

Jan 1, 1970

By E. Bonates

Dispatching systems have attracted considerable attention in the last years due to substantial gains in productivity achieved through their implementation. These systems will be extensively used in the future by mine operators as a means of optimizing productivity. This paper describes a computer simulation model designed to study the feasibility of continuously dispatching trucks in open-pit mines based on different operating procedures. The system developed is semi-automated and performs an active role by suggesting to the dispatcher the best assignment according to each specific circumstance. It is modeled based on an advance-clock increment to reduce computing time and allows the insertion of heuristic dispatching policies and equipment real-locations when breakdowns occur. Dispatching procedures taking into account long-term production objectives are considered in system development.

Jan 1, 1988

By S. Bhattacharyya

"Coal bearing rocks are low in strength and have geological discontinuities and moisture sensitivity. Roof and rib falls have been a major cause of fatalities in underground coal mines. Mine engineers design ground control plans for regulatory approvals. A number of tools are available from the National Institute for Occupational Safety and Health to design and assess these plans. Quite often there is not enough geotechnical input information available and databases are used. The Appalachian coalfields have extensive scientific studies to provide reliable regional inputs. Coal mines in the western United States and Canada have different geological and geotechnical conditions, and less available data. Use of inappropriate inputs in the tools like Analysis of Retreat Mining Pillar Stability, Analysis of Longwall Pillar Stability, and Analysis of Roof Bolt Systems may result in unsafe designs or over conservative designs. The tools are convenient but thorough understanding of the inputs, calibration with local test results, and operating experience are important for effective designs. The current paper contains examples of difficulties faced during mine planning using the above tools. INTRODUCTION Sedimentary rocks hosting coal are low in strength. Scientific studies have placed the uniaxial compressive strength (UCS), triaxial strength, tensile strength, and shear strength of sandstone, shale, siltstone, and claystone in lower range of strength among engineering materials (1). Coal bearing rocks are most often weakened by the presence of faults, folds, slickensides, bedding planes, fractures, and other geological discontinuities. The host rocks and coal are often moisture sensitive. The geological discontinuities allow water to enter the strata from surface and underground sources. This combination of low strength, structural weakness, and presence of water results in difficult ground control situations for the coal mines. Roof (2) and rib falls have been a major cause of fatalities in the U.S. coal mines. Modern underground coal mines necessitate wide entries to accommodate large production equipment. The gate roads, section entries, and the mains entries of a highly productive coal mine are as wide as twenty feet (6.1 m). The actual intersection width is nearly thirty feet (9.1 m). Adequate ground control is a key to maintain safe production in such mines. Mine engineers and their consultants routinely submit ground control plans to the regulatory authorities. While working out the necessary roof control system the mine engineers are required to demonstrate the adequacy of the proposed system. There are multiple ways to demonstrate this. Some engineers use traditional load calculation approach of roof bolts (3). Some engineers use numerical methods. Yet a large number of professionals resort to a suite of ground control design software offered by National Institute for Occupational Safety and Health (NIOSH) commonly referred to as “NIOSH Ground Control Toolbar.” These software tools are free and easy to download from NIOSH website. The software included in this package are: Analysis of Longwall Pillar Stability (ALPS), Analysis of Retreat Mining Pillar Stability (ARMPS), Coal Mine Roof Rating (CMRR), Analysis of Roof Bolt Systems (ARBS), Analysis of Horizontal Stress Effects in Mining (AHSM), Analysis of Multiple Seam Stability (AMSS), Analysis of Retreat Mining Pillar Stability - Highwall Mining (ARMPS-HWM). These tools are relatively simple to install and use in planning and designing coal mines and prospective coal mines. They accept a number of geotechnical inputs which are collected from either an existing mining operation or from exploratory boreholes. In the absence of necessary input parameters, the programs use default values which are drawn from databases of geotechnical properties built by NIOSH."

Jan 1, 2015

By R. G. Dalbke

An increasing number of water pollution control systems are certain to be installed by many industries in the future because of new federal, state, and local government regulations, and because of the rising general concern about the deterioration of our water resources. Extensive engineering, some of it based on methods not yet developed, will be required if these new systems are to provide optimum pollution control. Capital cost, operating cost, and present and future regulatory requirements will be primary factors to be considered by engineers. This paper outlines procedures and gives examples of advanced engineering practices that have achieved efficient pollution control systems in the steel and nonferrous industries.

Jan 1, 1968

By J. V. Thompson

The Powderhorn complex as a source of perovskite (calcium titanate) containing about 1.5% rare earths has been examined in several recent feasibility studies. Much promising exploration and process research has been done in recent years. This paper is presented with cautious optimism and with the acknowledgment that there may be some technical and economic areas yet to be explored. The Powderhorn carbonatite and alkalic stock in Gunnison County, Colorado, lies about 203 airlines km southwest of Denver at an elevation of 2450 to 2750 m (see Figures land 2). All of the mineable ore bodies are owned by Buttes Resources Company of Houston, Texas.

Jan 1, 1990

By K. Sharman

Quintette Coal Limited (managed and 50% owned by Denison Mines Limited) operates an open pit coal mine located in northeastern British Columbia, in the foothills of the Rocky Mountains. (See Fig. l). Mining commenced in 1982. The mine currently produces 4.75 million tonnes of medium volatile bituminous coal per year from three pits (Mesa, Wolverine and Shikano), using a truck/ shovel operation. (See Fig. 2). Conveyors and trucks transport run-of-mine coal to the heavy media/froth flotation process plan t, where it is cleaned and loaded into rail cars for delivery to the Ridley Island port at Prince Rupert, British Columbia. All coal is sold to the Japanese steel industry under a long term contract. The coal seams mined at Quintette are contained in the Lower Cretaceous Gates Formation. Mineable seam thicknesses vary from 0.6 m to 10 m. The regional structure of the area is typical of foreland fold and thrust belts, with open to tight folds and imbricate thrust faulting. The range of structural features found in the three pits, and their effect on mining, forms the subject of this paper.

Jan 1, 1991

By L. G. Austin

A simple finite difference algorithm has been used to compute a simulation model for unsteady-state ball milling. The model considers the mill to act as if it were three fully-mixed reactors in series (one-large/two- small), it incorporates the-Rogers-Austin mass transfer law relating mill hold-up to flow rate through the mill, and it allows for the reduction in breakage rates caused by over-filling of the mill at high flow rates. The computation is rapid and requires only small storage space. Examples are given of use of the model.

Jan 1, 1984