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By L. M. Turner

Perlite is a unique mineral that upon heating expands to about twenty times its original volume. Mining is by open pit method. The processing cycle involves crushing, screening and sizing the ore. An on-site quality control facility at the Manville Products No Agua mine exerts a high degree of control over every phase of the operation from blasting to finished product.

Jan 1, 1985

By M. Christou

The LIFE-Environment Demonstration Project ?Treating Waste for Restoring Land Sustainability?(www.bangor.ac.uk/ies/TWIRLS/TWIRLS_home.htm), a project initiated by the University of Wales, Bangor, UK in which NAGREF is a partner, aims to demonstrate the effective use of industrial and municipal wastes for the remediation of post-industrial and degraded sites in urban and rural sites. Within the framework of this project, a schist quarry, which is located in a mountainous area near Athens and which has been exploited in the past for cement production, was chosen for bioremediation experiments in collaboration with the quarry owners, TITAN Cement Co. Three different areas within the quarry were selected representing 3 different topographies. These were a compacted, flat area with seasonal water logging (untreated control), a gently sloping, land formed area; and artificially created mounds of overburden rock material formed on the flat area. Compost produced from mixing municipal waste, green waste and digested sewage sludge at the recycling plant of the Association of Communities and Municipalities in the Attica Region (ACMAR), near Athens was used for nutrient amendment. Six replicates of three treatments were applied with varying compost application rates in order to examine the effect of the addition of organic matter in the establishment of suitable vegetation on the infertile schist material. Pine trees (Pinus halepensis Mill.), 4 per replicate, were pocket planted in a volume of 3 liters of schist or schist-compost mixture (1:2 and 2:1). Tree height, main stem diameter and branching were measured following planting and these measurements will be repeated annually to test hypotheses that compaction and water logging reduce Pine establishment by natural regeneration and that nutrient addition improves establishment of pine on schist waste. The availability of nutrients and variation in other soil physico-chemical parameters will also be studied in each treatment and related to plant growth. As a demonstration project, open days are planned on the site for the public and official bodies involved in municipal waste handling and other relevant areas. The aim of these will be to illustrate the effective re-use of waste for the sustainable restoration of post-industrial and degraded land.

Jan 1, 2006

By T. W. Beck

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dust escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dusthog- type bit to improve dust extraction during the critical initial phase of drilling. A twistedbody drill bit is also evaluated to determine the quantity of dust liberated in comparison with the dust-hog-type bit. Based on the results of our laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emission can also be substantially reduced. The use of a twistedbody bit has minimal improvement on dust capture compared with the commonly used dust-hog-type bit.

Jan 1, 2014

By K. L. Whitehead, R. A. Jankowski, N. I. Jayaraman

Most continuous miner sections utilizing flooded-bed scrubbers also use blowing face ventilation. Blowing ventilation, however, interferes with dust capture and minimizes scrubber effectiveness. To enhance the efficiency of the scrubber system and reduce dust concentrations, the Bureau of Mines tested various combinations of operating parameters. Experiments for system efficiency took place in a full- scale model mine at 3.05 m roof height. In general, higher values for scrubber and face airflows resulted in lower dust concentrations. In addition, optimum dust controls would include a face ventilation to scrubber airflow ratio of one. When the airflow ratio was either less than or greater than one, the dust levels in the return and at the operator locations increased. No single dust control technique was the most effective one at all locations due to mutual interaction among techniques.

Jan 1, 1992

By D. A. Swanson, G. Danziger, G. Savci, C. Barnes

Hydrologic assessments of existing and proposed waste rock stockpiles are typically required for application of operating and closure permits at mine sites. A hydrologic assessment should include an evaluation of climatic data and prediction of the net infiltration rate through the waste rock stockpile surface. In addition, hydrologic factors such as the time required to deplete available moisture storage in the stockpiles and the time required for potential seepage to migrate to the underlying aquifer should also be predicted.

Jan 1, 2000

By E. K. Albert

Computer oriented simulation techniques can be effective in the design and analysis of complex mining systems. In fact, a number of computer software products are available for mine systems simulation. While providing a useful tool for the investigation of mine planning problems, the availability of graphic output was limited or non-existent. Computer graphics is a natural extension of mine simulation methods and provides a more dramatic level of understanding and interface with an engineer. With today's high cost of venture development, the need for an easy to use but complete systems model which includes the major elements of mine planning with an interactive graphics interface has never been more apparent. In this paper, the underlying philosophy of design of an interactive interface to a complete surface mining simulation model is described. The basic structures of the surface mining system and the simulation model are discussed. The methods and algorithms used to implement the various subsystems are presented. Practical considerations of the design of displays and user interaction are illustrated, especially as they apply to the application of the package by a mining engineer. A simple example is provided to demonstrate the concepts embodied in the model and to show how a simulation is built from mine data.

Jan 1, 1984

By Howard Lum, Sergio Valles, John Bednarski, Gordon Enas, Jay Arabshahi

"Water drawn from the Sacramento-San Joaquin Delta provides water supply to 66 percent of California’s population and supports the state’s agriculture industry. The existing through-Delta water system is outdated and unreliable with environmental risk to some fish and wildlife species. The Bay-Delta Conservation Plan (BDCP) has been established to environmentally retrofit and modernize California’s water delivery system through the Delta by restoring habitats, constructing new diversion points in the north Delta and providing a means to transport water supplies under the Delta, rather than through sensitive natural channels.Under BDCP, the Delta Habitat Conservation and Conveyance Program (DHCCP) has developed several alternatives to convey water from the Sacramento River in the north to the existing pumping facilities in the south Delta through an isolated conveyance system. The new conveyance system would become an integral part of the State Water Project (SWP) and the federal Central Valley Project (CVP) by transporting water to the export pumping plants for each of these projects. The DHCCP is managed by the California Department of Water Resources (DWR), while state and federal water contractors provide technical support to the program.The initial conceptual study efforts on the overall program commenced in 2007 and examined various options for the proposed conveyance system. Several conveyance alternatives were analyzed at that time. The Conceptual Engineering Report published on Oct. 1, 2013 identified the modified pipeline/tunnel option (MPTO) as the preferred alternative to be included in the BDCP environmental documents. MPTO includes three river intakes and pump stations along the Sacramento River, various sizes of pipelines and tunnels, junction structures and two forebays that are capable of delivering up to 4 million gpm (9,000 cfs) from the Sacramento River to the SWP and CVP. The river intakes are located near Hood in Sacramento County approximately 64 km (40 miles) from Clifton Court Forebay (CCF) in Contra Costa County. This route would cross portions of Sacramento, San Joaquin and Contra Costa counties. Figure 1 depicts the configuration of the MPTO alternative."

Apr 1, 2016

By Carson Rife, Michael L. Clark

INTRODUCTION Zortman Mining Inc. is a wholly owned subsidiary of Pegasus Gold Corporation of Spokane, Washington. Pegasus has been producing gold and silver from the Zortman and Landusky mines since 1979. The Zortman and Landusky mines are two distinct open pit mines located approximately 6 kilometers apart in the Little Rockies Mining District of north central Montana. The two mines use large-tonnage, low- grade heap leaching techniques to efficiently process the gold and silver ore. PROJECT DESCRIPTION The Little Rockies rise abruptly 914 metres from the surrounding plains to about 1829 metres above sea level. The topography is quite steep, making efficient leach pad construction a major challenge. The climate is semi-arid with moderate summers and occasionally severe winters. Freezing temperatures usually arrive in late October or early November, influencing the effectiveness of leaching operations. GEOLOGY AND MINERALOGY The geology of the Little Rocky Mountains consists of steeply dipping sedimentary ridges forming an elliptical dome surrounding a core of intruding syenite porphyry. Within the syenite porphyry are well fractured and mineralized shear zones where the existing reserves and open pits are located. The ore is presently divided into oxidized, mixed, and sulfide. Only the oxides and mixed zones that are of ore grade are placed on the leach pads. The syenite porphyry host rock enables effective leaching of gold and silver to depths of 61 metres, having a major impact on leach pad construction costs. MINING All mining since 1979 has been by contractor. This enabled initial mining to commence without capital investment in equipment. Through competitive negotiations, Pegasus has been able to keep contract mining costs at levels very close to what would be experienced if Pegasus had purchased equipment initially. Contracts are negotiated yearly and are based on a unit price and haul distance for ore and waste. Haul distances have ranged from as little as 457 metres to as much as 3,050 metres. At present, Pegasus is developing a 27,000,000-tonne leach pad at the Landusky project that is adjacent to the minine area. This design feature will reduce the mining cost by 20 percent over the life of the mine. In 1987, over 5,900,000 tonnes of ore and 3,200,000 tonnes of waste will be mined at the Landusky project. Through 1986, 13,763,000 tonnes of ore have been mined at a waste-to-ore strip ratio of 0.60:l at the Zortman project, and 13,005,000 tonnes of ore at a waste-to-ore strip ratio of 0.79:l have been mined at the Landusky project. Current mining reserves are 32,769,000 tonnes of ore at a waste- to-ore strip ratio of 0.59:l. Through efficiencies of large-scale heap leaching, Pegasus has been able to lower the mining cutoff from 0.34 grams per tonne gold to 0.27 grams per tonne gold. This has reduced the mining cost per tonne of ore h percent through a reduction in strip ratio of 14 percent. Beginning in 1984, all pits were designed based on computer-generated "floating cone" pits. The geologic models were developed by Pegasus staff with a series of economic models evaluated. The resulting computer-generated pits were used as a guideline in designing the mine plans, including haul roads for final calculation of tons and grade. Input to the floating cone models consisted of mining cost, processing cost, cutoff grade (0.34 grams gold per tonne), recovery (67 percent) and gold price. Due to the gold being deposited primarily on the fractures of the syenite host rock, no crushing of ore is needed prior to leaching. This characteristic of the ore is a key in being able to profitably mine and process gold ore at an average grade of 0.69 grams of gold per tonne. Strict blasting control is also a key in success of the leaching operation. A system of splitting ore and waste in blast patterns has been devised to reduce dilution. Also, drill hole spacings are varied from 3m x 3m in breccia ore to 4m x 4m in syenite ore to 5m x 5m in waste. Drill holes

Jan 1, 1987

By J. E. Litz

The hydrometallurgy review did not arrive in time for publication in the May issue. 1992 was not a banner year for hydrometallurgical installations or new hydrometallurgical developments. Installation of copper solvent extraction/electrowinning circuits were under construction or began operation in Nevada (Yerrington ), Arizona (SilverBell), Chile (Copiapo and Escondida), Peru (Toquepala and Cuayone) and Australia (Girilambone). These installations will produce more than 100 kt/a (110,000 stpy) of cathode copper. Several new heap leach gold facilities using conventional technologies were announced or were put into operation. New technologies undergoing widespread testing include biological oxidation of low-grade ores in a heap leach mode and evaluation of new agglomerating agents.

Jan 1, 1993

In phosphate flotation, more than 90% of the finer fraction (-35, + 150 mesh) is recovered as opposed to 70% of the coarser material (-16, + 35 mesh). On the other hand, coarser fraction is higher in phosphate content than the finer feed. Consequently, improvement in the coarse recovery is highly desired. It was determined on bench scale that emulsification of the collector (fuel oil and fatty acid mixture) can lead to enhanced recovery of coarse particles. Flotation of phosphate with emulsified collector resulted in improved recovery and grade also on the plant scale.

Jan 1, 1992

By A. Gupta, F. Hrach, L. R. Mendoza, K. Flynn

ST Equipment & Technology LLC (STET) has developed a novel processing system based on tribo-electrostatic belt separation that provides the mineral processing industry a means to beneficiate fine materials with an energy-efficient and entirely dry technology. In contrast to other electrostatic separation processes that are typically limited to particles >75μm in size, the STET triboelectric belt separator is suited for separation of very fine (<1μm) to moderately coarse (500μm) particles, with very high throughput. The STET tribo-electrostatic technology has been used to process and commercially separate a wide range of industrial minerals and other dry granular powders. Here, bench-scale results are presented on the beneficiation of low-grade Fe ore fines using STET belt separation process. Bench-scale testing demonstrated the capability of the STET technology to simultaneously recover Fe and reject 2 from itabirite ore with a D50 of 60μm and ultrafine Fe ore tailings with a D50 of 20μm.The STET technology is presented as an alternative to beneficiate Fe ore fines that could not be successfully treated via traditional flowsheet circuits due to their granulometry and mineralogy. INTRODUCTION Iron ore is the fourth most common element in earth’s crust [1]. Iron is essential to steel manufacturing and therefore an essential material for global economic development [1-2]. Iron is also widely used in construction and the manufacturing of vehicles [3]. Most of iron ore resources are composed of metamorphosed banded iron formations (BIF) in which iron is commonly found in the form of oxides, hydroxides and to a lesser extent carbonates [4-5]. A particular type of iron formations with higher carbonate contents are dolomitic itabirites which are a product of the dolomitization and metamorphism of BIF deposits [6]. The largest iron ore deposits in the world can be found in Australia, China, Canada, Ukraine, India and Brazil [5]. The chemical composition of iron ores has an apparent wide range in chemical composition especially for Fe content and associated gangue minerals [1]. Major iron minerals associated with most of the iron ores are hematite, goethite, limonite and magnetite [1,5]. The main contaminants in iron ores are 2 and Al2O3 [1,5,7]. The typical silica and alumina bearing minerals present in iron ores are quartz, kaolinite, gibbsite, diaspore and corundum. Of these it is often observed that quartz is the mean silica bearing mineral and kaolinite and gibbsite are the two-main alumina bearing minerals [7]. Iron ore extraction is mainly performed through open pit mining operations, resulting in significant tailings generation [2]. The iron ore production system usually involves three stages: mining, processing and pelletizing activities. Of these, processing ensures that an adequate iron grade and chemistry is achieved prior to the pelletizing stage. Processing includes crushing, classification, milling and concentration aiming at increasing the iron content while reducing the amount of gangue minerals [1-2]. Each mineral deposit has its own unique characteristics with respect to iron and gangue bearing minerals, and therefore it requires a different concentration technique [7].

Jan 1, 2019

By P. R. Wotruba

The Fortitude gold-silver deposit is related to a "wallrock" copper porphyry system developed within Middle Pennsylvanian to Permian Antler Sequence rocks adjacent to a Middle-Tertiary altered granodiorite intrusive stock at Copper Canyon. Gold-silver ores of the Fortitude deposit occur with disseminated and massive sulfide replacement mineralization of skarn-like or calc-silicated limy horizons of the Antler Sequence contact meta-sedimentary rocks. A major, north-trending, steeply westward dipping normal fault was important as a conduit for hydrothermal fluids responsible for the metallization in the Fortitude area. Gold-silver mineralization is best developed near a marble front where retro-grade chloritization and destruction of prograde calc-silicate mineral phases is most prevalent. Fluid-inclusion studies performed on the Copper Canyon system indicate a wide variation in fluid chemistry during several hydrosilicate stages that ranged in temperature from 500°C to 220°C.

Jan 1, 1986

By V. Rajaram

The oil shales located in the Appalachian Basin cover an eight-state area of the eastern U. S., and are referred to as Devonian (black) shales. These shales have been exploited for their gas potential for several years. The Institute of Gas Technology (IGT) has conducted research since 1972 on the production of shale oil from the Devonian shales, and this resulted in the development of the HYTORT process. This process demonstrated that the yield from the Eastern oil shales can be greater than the value indicated by the Fischer assay method. IGT estimates that 423 billion barrels (67.3 x 109 m3) of oil could be recoverd by HYTORT processing of surface-minable eastern U. S. shales. Recently American Syncrude Corporation and Southern Pacific Petroleum N. L. have proposed oil shale projects in Kentucky. This paper will describe the surface mining and retorting techniques that have been studied for exploitation of the Devonian shales, and enumerate the problems that have to be overcome before commercial production can be realized from these shales.

Jan 1, 1983

By Allison L. Hornbaker

Millions of years ago, in late Cretaceous time before man existed on Earth, tremendous orogenic forces began to change the face of the western part of the North American Continent. Catastrophic events marked by huge uplifts of thousands of square miles in the Cordilleran Belt, some of which are barely discernible in the geologic record, were accompanied by long periods of batholithic intrusions and volcanic eruptions. These events produced the great Rocky Mountain systems, which were at the time even higher and more rugged than they are today. Such activity continued into Tertiary time, and during the Pliocene and Pleistocene periods millions of tons of volcanic ash were hurled skyward by explosive volcanic activity and carried by the westerly winds to the east where it settled out of the atmosphere and deposited over thousands of square miles of the high plains. Unusually heavy rains, probably caused in part by the volcanic activity itself, together with high winds, reworked and redeposited the freshly fallen ash into lakes and depressions of varying sizes and shapes. Subsequent deposits of sand, gravel and loess covered the deposits of volcanic ash, preserving them in the condition in which they are found today. In many places erosion has cut through the sand, gravel, loess, and volcanic ash so that in favorable localities on hillsides and gullies, exposures of volcanic ash can be seen interbedded with sand and gravel.

Jan 1, 1970

By Mark Godfrey, Wickus Slabbert, Debra Miller, Dave Dew

Sao Bento Mlnerai;;ao Mine (SBM), located 100 kms northwest of Belo Horlzante, Brazil, was commissioned In 1987t1l to produce 185 kg per month of gold from 240 tpd of refractory sulphide flotation concentrate. The concentrate Is processed by a Sherrill Gordon design pressure oxidation circuit followed by conventional CIL gold recovery process (Flgur .. J). The original plant design foresaw expansion to 480 tpd, and In this regard the acidic effluent neutralisation, CIL and carbon circuits were designed for future expansion to treat the higher tonnage. The pressure oxidation section was sized for 240 tpd with the Intention to double the Installed plant equipment to provide 480 tpd capacity when required. This decision was based In part on the novelty of pressure oxidation to treat refractory sulphide concentrates in 1984 when the process design was finalised. General Mining, Metals & Minerals (Pty) Ltd (GENMIN), has been actively Involved for the past 30 years in the development of bacterial process for the oxidation of refractory gold concentrates; the results of this development program have provided the registered process BIOx®. The successful Implementation of BIOx® technology for treatment of refractory gold concentrates at GENMIN's Fairview Mine In October 1986t2l, as well as the substantial experience accumulated in laboratory and pilot testing of some 40 other sulphide concentrates, Justified reconsideration of the oxidation process best suited to provide the Incremental sulphide oxidation capacity planned for SBM.

Jan 1, 1992

By J. M. Gambogi

Demand for titanium minerals and pigments was nearly unchanged in 1996 compared with 1995. However, through mine expansions and process optimization by the TiO, pigment industry, the available supply of titanium minerals and pigments increased moderately. At the end of 1996, exploration, development and expansion programs were ongoing in the mining sector. But expansion projects in the pigment sector were delayed pending increased demand.

Jan 1, 1997

By D. L. Boreck

With increasing land development, the potential of fatalities from abandoned mine shafts increases. To minimize potential liability, shaft closure should be a critical part of mined land reclamation. The Bureau of Mines is conducting research into using lightweight foam concrete in sealing abandoned coal mine shafts. A demonstration seal consisted of a 3m thick foam concrete plug to provide lateral stability inside the shaft. A high density concrete cap provided load-bearing capacity for a 100-year service life. The USBM has also completed research into changes in foam concrete when it is pumped or dropped from different heights. It is concluded from the research that foam concrete can undergo significant air loss with pumping or dropping. This foretells significant changes in the characteristics of the concrete as well as an increase in the weight and cost of the in-place concrete seal. When using foam concrete to seal abandoned mine shafts, care must be taken to minimize air loss during placement.

Jan 1, 1994

By L. J. E. Hofer, L. F. Zeiler, D. A. Giardino

The Jones Trickett Ratio (JTR) is generally used in investigations of fires and explosions for the determination of the composition of the fuel. This paper takes a close look at the JTR and finds it unreliable and ambiguous for the determination of fuel composition. A new index is presented, termed the (H/C) Index which uniquely determines the fuel composition. The (H/C) Index is simple to use requiring only the results of a single gas analysis of the combustion products. Experimental data testing the (H/C) Index for methane, propane, ethylene and coal dust are given, showing that the Index unambiguously determines the composition of the fuel. The (H/C) Index is also applied to the gas analysis data of several mine fires, illustrating how the Index changes with the progression of the mine fire.

Jan 1, 1993

By R. F. McFarlin, H. E. El-Shall

Since its inception, the Institute of Phosphate Research has examined every promising proposal in order to find an economical, practical and environmentally sound method of dewatering phosphatic clays. The in-house development of the FIPR/DIPR process (DIPR = Dewatering Instantaneously with Pulp Recycle) would appear to answer that quest. When small amounts of fibrous materials are mixed with clay slurries and flocculent, rapid dewatering occurs. Clay solids contents of 20 to 25% can be attained by simply rolling the clay mass down an inclined screen. Higher solids (>40%) are reached by physically pressing the cake; e.g., with a belt press. Because mechanical pressing devices are too expensive for phosphatic clay treatment, FIPR has developed the "sandwich" method of simultaneously dewatering the phosphatic clays and reclaiming the mine cut, as well as a second alternate, the "median strip" proposal. Economic projections of these bench-scale alternates suggest that the FIPR/DIPR process should be no more costly than present practice, when credit is given for the simultaneous reclamation accomplished.

Jan 1, 1993

By Alexander N. Winchell

"Location. The Cuyuna iron district extends from the region of Kimberly, near the Center of Aitkin County, Minnesota, south-westward through Deerwood, Ironton, and Brainerd, across Crow Wing and Todd counties, across the Mississippi River, and for an unknown distance farther southwest in the same direction. It is known that the Huronian rocks, in which the ores of the Cuyuna district are found, reappear near the western border f Minnesota, but no ores have been found in this region. The district has a length of more than sixty miles, but the more important portion as now known &apos;is confined to Crow Wing County in an area which is less than thirty miles in its longest dimension. The commercial headquarters for the district are in the city f Brainerd, on the Mississippi River.History. The discovery of iron ore in the Cuyuna district was accomplished with no aid from surface outcrops, but solely through the use of the dip needle. The mantle of glacial drift overlying the iron formation varies from twenty-five to 359 feet in thickness, and it was by means f the magnetic attraction of the iron bearing rocks that their presence was discovered with the dip needle by Cuyler Adams, about 1895. The general geologic map of Minnesota, published by the State Geological Survey in 1909, showed the extension of the Huronian rocks of the Mesabi district passing through this area. Two years later, Leith published a sketch showing the hypothetic extension of the iron bearing formation through the same area. The first drilling was done in 1903, near Deerwood, Minn., by Cuyler Adams, and exploration was continued to the present time in increasing amount. The Northern Pacific Railway extends throughout the length of the district and affords an easy outlet for the ores. The Soo Line Railway completed a spur into the district in 1910. Both roads carry the ore to the docks at Supe¬rior, Wis., the average haul being about ninety miles. Shipments began in 1911, the Kennedy mine being the first producer. By 1918, the number of shippers reached twenty-seven, with a total output of nearly two and one-half million tons for that year."

Jan 1, 1920