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By I. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of Papua, Indonesia. This district consists of both underground and surface operations. The East Ertsberg Skarn System (EESS) is one of the major orebodies in this district. Subsurface caving of the EESS has been carried out in a systematic series of mining lifts dating back almost 30 years. Present production is from the third lift (Deep Ore Zone), which is scheduled to peak at 80,000 mtpd during 2009, with this rate sustained through 2015. The orebody is proven below the existing caving level, with the next vertical block called the Deep Mill Level Zone (DMLZ). This paper presents an overview of the DMLZ Mine based on recent feasibility level study. The mine is being designed for a peak production rate of 29.2 million mtpy, with 1,803 total ore draw points spread over a panel caving footprint of about 1.3km by 375m. The present reserves for this mine total 501 million tonnes. Located 1,400-1,800m below the original surface, the DMLZ will be one of the deepest caving operations in the world. Production is scheduled to commence in 2015. Discussion is provided on most design aspects including; caving methodology and layouts, geotechnical predictions and risks, ore handling systems, ventilation design and associated infrastructure, high-lift pumping system, cost estimation and expenditure scheduling.

Jan 1, 2010

By J. L. Boyd

The mining and processing of basic metals relies on water as a medium for transport. Metallurgical ores are ground, concentrated, leached and refined in an aqueous medium. Water is used for temperature control during processing and in air pollution abatement during smelting. All of these process steps result in liquid wastes. Many of the aqueous wastes from ore processing areas become the raw product for a second stage and water recycling may begin. The point at which water recycling or reuse has been initiated in the past, rather than water discharge, was where water conservation was manditory due to a shortage, where process conditions would allow or benefit from reuse, and where economic considerations demanded reuse. The Fontana, California plant of Kaiser Steel Corporation is an example of an integrated steel plant that was forced to practice water conservation and reuse due to its location in an arid environment.1 Only a small amount of water required to maintain the water reuse system in balance with respect to dissolved solids and product quality is discharged. The Butte, Montana copper ore processing plant of The Anaconda Company obtains 66% of the water required for production by recycling, after clarification and chemical treatment, 30 MGD of wastewater from its tailings ponds. This operation is estimated to save the company about $1200/day over a once through water system.2 Here plant location and economics favored water reuse.

Jan 1, 1975

By F. C. Townsend

Centrifugal modeling was used to evaluate reclamation schemes of; (a) flocculants, (b) sand/clay mixes, (c) flocculants/sand addition and (d) capping with sand or sand/clay mix. Results suggest the hierarchy of effectiveness is: (d) capping, (b) s/c mixes, (c) flocculants/sand addition and (a) flocculants. Comparisions between currently used large strain consolidation computer programs reveal no difference between piecewise linear or finite strain calculations. Correlations between numerical and centrifugal model predictions reveal excellent agreement on magnitudes; however, rate predictions require improvement in laboratory input data and centrifugal scaling relationships.

Jan 1, 1987

By H. R. Coles

Test work conducted in the 6.4 and 10.52 m Aerofall Mills at the Iron Ore Company of Canada Carol Project showed that the conventionally used ?deflector?-type liners which form the basic principle of Aerofall Mill grinding did not necessarily provide the best grinding performance. A new design, using low profile liners incorporating radial ribs of a proper height, actually improved the mill throughput in the order of 9 to 20% without sacrificing grinding efficiency. In addition, the new design reduced liner weight and scrap losses, which resulted in a reduction of liner consumption by 25%. It provided better protection to the mill shell and reduced the overall maintenance cost for the mill

Jan 1, 1980

By Jinrong (Patrick) Zhang

Improvement of conventional flotation efficiency, separation of carbonates from apatite, recovery of phosphate values from phosphatic clay and other ways of utilizing the clay, disposal of clay slurries and subsequent reclamation of the settling areas, and conservation of resources and energy remain major challenges in the beneficiation area for the phosphate industry. These problems have been actively investigated by the industry, government agencies, and research organizations for decades with modest success. However, some recent research activities have generated promising results and possible new technologies. The dominant position of the Crago process in phosphate beneficiation is being challenged by some of the single stage processing schemes. Heavy media separation enables one producer to process a portion of high carbonate ores. Separation of dolomite from apatite by reverse flotation of carbonates with phosphate depressants showed potential for industrial application. Consolidation of phosphatic clays in mine cuts using a modified "sandwich" process is being tested. Beneficiation in the acidulation plant or grinding at the mines may be considered in the future.

Jan 1, 1993

By P. Roghanchi

The difficulties associated with performing direct tensile strength test lead to development of indirect test methods, which are simple, less expensive, and less time consuming. Splitting tensile strength test (Brazilian test) is performed by applying two opposite concentrated compression load across the diameter of a disk specimen until the failure occurs along the loaded diameter. Theoretically, the load is applied over a small width as a line load, however, by increasing the load, the contact width between the loading jaw and the specimen increases as the specimen deforms. The main aim of this study is to investigate the stress distribution in (1) regular Brazilian specimen in traditional tests with loading jaws and (2) flattened Brazilian specimen with flat platens. A series of the splitting tensile strength tests and uniaxial compression strength tests are performed on three rock types: rhyolite, basalt, and limestone. Further, Numerical modeling studies are performed to investigate the effect of the contact between jaw and Brazilian specimen on stress distribution in the disc specimen based on the results from the experimentation. Finally, the stress distribution in the traditional Brazilian test specimen and the flattened end Brazilian test specimen were compared.

Feb 23, 2014

By G. Hoffmeyer, I. Ream

"Several copper projects exclusively utilizing in-situ recovery methods are currently under development in Arizona. Favorable conditions for In-Situ Copper Recovery (ISCR) include a saturated orebody, fracture hosted mineralization, hydraulic conductivity sufficient to effectively inject and recover solutions using wells, and a relatively flat background hydraulic gradient. Safe operation of an ISCR project requires that the operator have the ability to induce and maintain localized hydraulic gradients, thereby controlling the movement of injected and recovered solutions. Benefits of ISCR include reduced initial capital, and a greatly reduced environmental footprint. THE ISCR METHOD EXPLAINED The method chosen to extract a mineral from a deposit is driven by characteristics such as its size, grade and depth of burial. Large lower grade deposits that require significant excavation to access using surface methods are potential candidates for in-situ recovery. ISCR may also be ideal for smaller deposits due to the lower initial capital. However, regardless of the size of the deposit, certain hydrogeologic conditions must be present for ISCR to be successful. In-situ recovery methods do not require excavations of rock from the surface or underground, resulting in a dramatic reduction in surface disturbance when compared to conventional mining. With the ISCR method, what is visible above ground is the processing plant, well heads, piping, process solution impoundments and evaporation ponds. There are no waste rock piles, tailings impoundments, leach pads, or impacts associated with blasting and hauling. Other benefits include reduced initial capital, reduced dust and noise, and lower water use. Early testing of the in-situ copper recovery method by Occidental on the Van Dyke deposit east of Phoenix and by Kennecott at Safford Arizona in the 1970s produced encouraging results, but the permitting regime for a large-scale operation was not yet in place. Additional testing and commercial application of in-situ copper recovery techniques have expanded since the 1980s, most commonly in conjunction with open pit or underground mining operations. For example, several operations in Arizona (San Manuel, Miami East and Tohono) have used in-situ techniques to extract additional copper following conventional mining from parts of the deposits adjacent to open pits or underground workings. Where the rock has been broken up by conventional methods, the method is called “in-place” leaching. The US government has also been involved in assessing in-situ techniques. For example, joint research was conducted by the US Bureau of Mines and industry on the Santa Cruz deposit in Arizona; and both federal and state agencies have been involved to establish the comprehensive permitting regime that exists today. Currently there are several projects in Arizona being evaluated as stand-alone ISCR operations."

Jan 1, 2016

By Robert D. Thomson

Land use is the single most important element affecting the quality of our physical environment. .The minerals industry is a user of land and by its very nature, directly affects the landscape. Mining is a very visible activity. Producers of sand and gravel, crushed stone, clay, cement and lime operate right at the interface of the public. These production sites must be located near population centers. People are more travel oriented than years ago and through use of the expanded interstate highway system visit remote and little-visited areas. They visit communities on their vacations, places they enjoy on weekends and places they drive past on business trips. Although not residents of these localities, they have a strong interest in changes that occur in the landscape. As a result, the public has a greater concern today about mining and its use of land. From 1930 through 1971, the minerals industry used 3.65 million acres, or 0.16 percent of the land mass in the United States (4)2/. Of the total 3.65 million acres utilized, about 59 percent was accounted for by the area of excavation, 20 percent by disposal of overburden and other mine wastes from surface mining, 13 percent by disposal of mill or processing wastes, and 5 percent by disposal of underground mine wastes; the remaining 3 percent was subsided or disturbed as a result of underground workings. Nonmetallic minerals and fossil fuels each accounted for 43 percent of surface land used during 1930-71; the metal mining industry utilized the remaining 14 percent.

Jan 1, 1976

By G. E. S. Valadao

Filtration is an important solid liquid separation technology employed widely in the mineral processing industries. The effectiveness of the filtration operation can be influenced by numerous variables, related to the particulate phase, the slurry rheology and the equipment. The classical approach for analysis is based on Darcy's law. Knowledge of the cake pore microstructure and its correlation to macroscopic cake properties is required to model the filtration operation from a fundamental point of view. Since cake formation seems to occur randomly, a 3D Monte Carlo method was used to simulate cake formation. The configuration for simulation was a space with width of 500 µm, length of 500 µm and height of 4000 µm. Size distributions of five different industrial products whose particle size distributions follow the Rosin Rammler distribution function were used. The particle shape was assumed to be spherical. The simulated cake structures were described in terms of volume porosity (volume of pore space per unit volume of cake) and surface porosity (area of pore space per unit area of a cross section). The results indicate: I) it is possible to simulate 3D packing, which mimics cake structure, using the Monte Carlo method, 2) segregation phenomena occurs during simulated cake formation, 3) the values of calculated porosity for simulated samples B, C, D, and E were lower than those determined for corresponding industrial products Br, Cr, Dr, and Er, and 4) some structures of simulated samples seem to correlate with laboratory leaf test data obtained for different products from plant operations.

Jan 1, 1999

Within the research project "Mine Development" funded by the "Austrian Fonds zur Forderung der wissenschaftlichen Forschung (FWF) " (funds for scientific research) between 1991 and 1993 150 underground hardrock mines in Europe, Northern America, Australia and Japan have been visited to analyze their general design and layout. The main aim of the project was to develop strategies for accessing new underground hardrock mines and to establish a mine planning database. The investigation included mines in high developed countries only, with a comparable labor cost situation. This paper presents the results of one part of the project, which deals with investigations into the influence of different parameters on the design of the primary access for a mine.

Jan 1, 1995

By G. Vik, P. Chryssanthakis, S. C. Bandis, L. Haruik, N. Barton, M. Christianson, A. Makurat

The large jointed chalk reservoir situated at 3 km depth in the North sea's Ekofisk field is undergoing major compaction after nearly 15 year of oil and gas production. Approximately 150 km 3 of the overlying sediments, mostly shales, are involved in the subsidence. A maximum central subsidence of nearly 3 meters, and a maximum present rate of 45 cm per year has set in motion numerous studies of the phenomenon. Non-linear finite element (FEM) and non- linear distict element (DEM) analyses of the compaction and large scale subsidence were performed. Consistent differences between the continuum and discontinuum analyses were noted. In the latter, slip on hypothetical bedding planes and sub- vertical or vertical faults was allowed, which possibly gives a more realistic simulation of the real processes of subsidence in such a large body of rock. Laboratory studies of the reservoir joints included roughness measurement, JRC and JCS characterization, direct shear tests while saturated in heated Ekofisk oil, and coupled closure-shear-flow tests with heated oil followed by heated sea water. Discontinuum modelling using Cundall's UDEC was performed on representative jointed assemblies (two sets of steeply dipping conjugate joints) to investigate the effect of a major reduction of pore pressure within the deformable matrix and along each joint. It was found that the large shrinkage deformation of the matrix allowed joint shearing to occur despite the constraint of uniaxial strain. Relative mass bulking due to small but widely distributed joint shear possibly explains the observed maintenance of excellent productivity despite large vertical strains in the reservoir.

Jan 1, 1986

By Susan T. Bagley, Linda D. Gratz, Kirby J. Baumgard

The extensive use of heavy-duty diesel engines in underground mines has raised concerns about the potential adverse health effects to miners exposed to diesel particulate matter (DPM) which contains mutagenic and carcinogenic organic compounds. The purpose of this study was to compare the levels of DPM, biological activity, and polynuclear aromatic hydrocarbons (PAH) attributable to diesel engines in underground coal mines and similar data collected in engine laboratory facilities to assess whether laboratory data could be used to predict in-mine levels of diesel emissions. Mean in-mine DPM and SOF concentrations varied from 0.90 to 1.9 mg/m3 and 0.08 to 0.40 mg/m3, respectively. DPM-associated mutagenicity (mean) levels at two of the mines varied from 400 to 970 revertants/m3. Concentations of three PAH differed by up to four-fold between two of the mines, largely reflecting differences in DPM and SOF levels. The laboratory raw exhaust data were divided by 100 to obtain expected or predicted values for in-mine concentrations. The predicted DPM, SOF, mutagenicity, and PAH values based on laboratory samples were not significantly different from many of the in-mine values. Using a potential in-mine dilution ratio range of 20 to 200:1, virtually all in-mine data fell within the predicted range. Therefore, an estimate of in-mine concentrations can be determined by evaluating laboratory data. This will allow for extrapolations from laboratory tests with particulate emission control devices to assess potential health-related benefits due to their in-mine use.

Jan 1, 1991

By B. Mishra, Q. Shi, Y. Zhao, G. Zhao

Shale is anisotropic due to the presence of bedding planes. The anisotropic strength of shale has been extensively studied. However, little attention has been paid to the size effect on shale strength considering the anisotropy. This research uses the discrete element method to study the size effect on the strength of shale under the uniaxial stress state. It is assumed that the anisotropy is caused by bedding planes, while the size effect is caused by randomly distributed flaws. The numerical model of shale comprises three components: shale matrix modeled by bonded particles (2) bedding planes modeled by smooth joints (3) flaws modeled by discrete fractures. The developed model is scaled to different sizes and tested in the uniaxial compression and the direct tension tests. The test result show that the uniaxial compressive strength decreases as the specimen size increases when the loading direction is perpendicular or parallel to bedding planes. The uniaxial compressive strength is determined by the flaws while the bedding planes only play a limited role. However, the size effect on the direct tensile strength depends on the direction of bedding planes. When the loading is perpendicular to bedding planes, the size effect is not prominent. The direct tensile strength is determined by the bedding planes while the flaws have little effect. When the loading direction is parallel to bedding planes, the direct tensile strength decreases when the specimen size increases. The direct tensile strength is determined by the flaws while the bedding planes have little effect.

Mar 2, 2022

As we are all well aware, the demand for coal is increasing very rapidly. This makes the coal industry one of great opportunity for both the miner and the-supplier. Up until the middle 1960's, the price of coal had been one of the most stable of all commodities for the proceeding fifty years. In somewhat oversimplified terms this was because the inflationary tendencies had been offset by improved mine techniques and more efficient, more productive, and more reliable equipment; but, in the last seven years the price of coal has doubled. It is not the intent of this paper to discuss the many reasons for this price increase, but to show how the cost of hauling coal can be sharply decreased with a new truck concept. Not long ago a mining executive stated that all haulage trucks now available are basically the same. They look the same; they cost about the same; they have the same engine, power train, and tires; and, they have about the same operating cost. Truck size has increased which has reduced the number of drivers, but the purchase price and maintenance and repair costs have increased proportionally. Pits must be widened and loading shovels enlarged, out, all this has not reduced the cost of moving coal. Another executive said that he saw no advantage in buying new trucks because his people now know how to maintain and operate the ones they presently have. They have all the right spare parts along with a good maintenance program. Most replaceable parts of the trucks now in operation have been replaced and improved at least once and the trucks are now running better than when they were new. Besides, the trucks are no pretty well written off.

Jan 1, 1972

By A. D. Davis

The Bear Butte Creek watershed, in the northern Black Hills of South Dakota, shows the effects of past mining activities in the form of dissolved metals and arsenic in stream water. Bear Butte Creek, during normal flow periods, loses all of its discharge to sinkholes that recharge the Madison Limestone aquifer. This work focused on the geochemical transport and fate of arsenic and on understanding ground-water flow conditions in the Madison aquifer through development of a three-dimensional ground-water flow model that was coupled to a geographic information system (GIS). Stream sampling and discharge measurements helped determine sinkhole losses and loading rates. Column laboratory tests provided data on arsenic adsorption and the mixing of stream water with aquifer water, which also was simulated with the geochemical models, pHREEQE and NETPATH. The models and GIS can be updated with new information and will be useful in managing the water quality of the Madison aquifer.

Jan 1, 1997

By Richard L. Sanford

The generalized rail haulage simulator described in this paper is an outgrowth of the need to expand a previously developed single level simulator to permit analysis of production problems where intermediate car storage is used. Many of the ideas of the former single level simulator, which is an integral part of an Underground Generalized Materials Handling Simulator (UGMHS), have been used in model development. In addition, experience gained in applying the earlier model to a variety of operating conditions has been heavily relied on. The generalized rail haulage simulation model can operate as an independent system and, as such, can be used to analyze rail haulage systems using production distributions as data input. In addition, this model is designed to replace the present rail haulage sub-assembly in the UGMHS model and the linking procedure has been integrated into the model. The flow of coal from production sections in UGMHS, for example, fill the mine cars and a condition of no empty cars at a loading station will shut down in by production systems.

Jan 1, 1974

By J. A. Haggman

In a country richly endowed in mineral wealth, Climax Arimco Mining Corporation's (CAMC) Dinkidi porphyry Au?Cu deposit in Nueva Vizcaya province, Philippines, represents the most significant mineral discovery in the country in recent times. The deposit is located within a belt of young intrusive and volcanic rocks in the Sierra Madre mountain chain of north Luzon a region previously unassociated with porphyry-style mineralization. Since 1989, drilling of the Dinkidi deposit has outlined a resource of 124 million tonnes of 1.0 g/t gold and 0.41 % copper. Regional exploration throughout CAMC's 37,000 hectare FTAA has identified a further sixteen potential porphyry-related deposits. A new mining law was passed in March 1995 but prior to that CAMC had the first Financial and Technical Assistance Agreement (FTAA) granted by the Philippine government allowing 100% foreign ownership of mining projects.

Jan 1, 1997

By R. R. Klimpel

This paper discusses the effect of water chemistry, reagent type, and other environmental factors on the performance of sulfide mineral size reduction and froth flotation processes. Two specific problems will be discussed: 1) the importance of appropriately utilizing the electrochemical window that is created in the grinding process to enhance sulfide mineral recovery by froth flotation; and 2) the impact of steel grinding media versus autogenous grinding on the efficiency of sulfide mineral flotation with varying thiol collectors and water sources.

Jan 1, 1996

By C. F. Meyer

The recirculation of mine air in an underground colliery, has always been regarded as a hazardous practice in South African collieries. The Mines and Works Act and Regulations states that fresh air, flowing Into an underground section, must flow out directly into the return airways after being utilized once in the section. One of the largest producing underground collieries in South Africa, Initiated a project on controlled recirculation with the permission of the South African Government Mining Engineer. The project involves the recirculation of 65 m3/s of air inside a ventilation district which serves a total of six production areas. The aim of the project was to increase the airflow to the sections without altering the existing ventilation system. Tracer gas studies were carried out to determine the actual distribution of the recirculated air to the individual areas. The results showed that an effective 54,18 m3/s of the recirculated 65 m3/s reaches the sections. This gives an air utilization figure of 83,4 per cent. Dust surveys were also carried out as part of the project to determine the effect of the recirculation of the return air on airborne dust levels. The results showed that the dust levels remained constant in the main intake and return airways and that no hazardous situation was being created. The project proved to be successful and showed that controlled recirculation can be executed and used as a solution for the supply of air to sections without endangering any lives.

Jan 1, 1993

If the communication/tracking system of an underground mine is severely damaged in a large mine accident or explosion, a surface based seismic system could be the only available tool for locating any trapped miners. This paper documents a field test of a seismic system at a room-and-pillar coal mine in Eastern Kentucky. Testing was performed at 6 different depths (450, 575, 750, 1175, 1525 and 1700 ft) above the mine. For each location underground, the miners pounded a ?set? of 5 ?repetitions? on the roof with each repetition being about one second apart. Over the 3 day field test, 63 sets of underground miners? pounding were detected by the seismic system at depths up to 1175 ft and at horizontal offsets up to 890 ft. Also during the testing, the observed signal strength generated by pounding with a crib blocks was seen to average 180% stronger than the observed signal strength generated by pounding with a sledgehammer. Ultimately, this field test was very successful and definitively demonstrated the ability of the seismic system to detect potential trapped miners? pounding up to a depth of 1175 ft.

Feb 23, 2014