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By M. Morrongiello

The Kalgoorlie Consolidated Gold Mines Fimiston Open Pit is mining through a dense network of disused level workings and stopes of varied sizes and orientations. This study investigated the interaction between underground workings and the pit slope stability, in particular for the ultimate pit depth of over 600 metres. Parametric analyses were conducted on the structural and rock mass properties in order to provide realistic input. Several cases in both 2D and pseudo 3D using UDEC were modeled and analyzed to investigate the performance of the rock mass at various mining stages. The concept of equivalent property factor was also introduced to model the 3D behavior using 2D models. Based on the modelling results, the possible failure mechanisms and deformation of the pit walls were assessed. Factors of safety have been derived for the pit slope at different mining stages using the strength reduction technique. The modelling results agree well with pit performance monitoring results to date. The concept and results presented in this paper could be a useful reference for operations with similar circumstances and stress regimes.

Jan 1, 2005

By R. T. Hukki

The paper describes a two-stage industrial hydraulic classification system including hydrocyclones for primary classification and newly developed cone classifiers for secondary classification. Performance data based on large scale grinding and classification tests are presented.

Jan 1, 1981

By S. N. McIntosh

Column bioleaching was evaluated by the U.S. Bureau of Mines as a means of recovering manganese from a low-grade ore from the Three Kids deposit in Southern Nevada. Manganese was solubilized from the ore using indigenous heterotrophic microorganisms. Diluted molasses medium was provided as nutrient for the microorganisms. The medium was recirculated through the ore bed until the sugars were spent. Two methods were evaluated to recover manganese from the sugar depleted bioleaching solution: (1) adsorption with a weak cation exchange resin followed by stripping and precipitation techniques, and (2) direct precipitation of the manganese using ammonium carbonate. Both methods removed up to 95 pct of the solubilized manganese from the medium as a carbonate salt. After manganese removal, the medium was replenished with fresh molasses and recycled back through the column. More manganese was effectively leached. This process of manganese solubilization and recovery followed by replenishment and recycling of the medium was repeated until 98 pct manganese was extracted from the ore.

Jan 1, 1993

By R. L. Wiegel

Some of the mineral deposits that are being processed today, and especially those expected to be processed in the future, have relatively low compositions of the valuable mineral. With these low-grade ores, it is necessary to be able to design processes that are sufficiently low-cost to permit exploitation. One approach to minimizing the capital and operating costs for these processes is to use the capabilities of computer process simulation in the design phase of development, to make important technical and economic decisions regarding the evaluation of alternative process flow schemes, the selection of equipment and the choice of operating conditions. There are mathematical simulation models for most mineral processing operations, including several each for size reduction, size classification and mineral separations. To be able to tie these individual operating models together in an integrated mineral process simulation, however, it is important, in fact in some cases essential, that there be a model which describes how the mineral system responds to size reduction in making the liberated valuable and waste mineral particles available for concentration or rejection operations and the locked particles available for possible recirculation. This, then, is the role played by the mineral liberation model, showing the relationship between particle size, quantity and composition throughout the process.

Jan 1, 2011

By R. C. Karra

Mining is one of the oldest profession and second after agriculture. Unfortunately Mining is not so familiar in the society. Due to lack of recognition in the society, existence of mines in remote places and in dusty and humid working conditions, led the poor response for mining engineering. Mining engineering programs have been increasingly less attractive to the student population over the years due to negative image of mining industry. After graduating in mining engineering, there is not much problem of employment at present. In the last 10 to 15years most of the mining engineering graduates have joined software industry. Even those joined in mining industry also left with in 2 years of service. The main reason for this is not being satisfied with job, it is not only working conditions but also work environment, work culture, remote location of the mines etc. Though many were trying to leave mining profession, the recent economic slow down has prompted some of them to incline towards job safety and retained to mining job. At this juncture a systematic study was taken up to analyze the job satisfaction of mining engineers in India.

Jan 1, 2011

By A. Bruynesteyn

The results of leaching experiments in columns simulating 80 and 200 ft deep cores through a leach dump are discussed, By equipping the columns with can precipitation plants, actual plant conditions could be duplicated. The results produced a better understanding of the physical and chemical limitations of the leaching process.

Jan 1, 1975

By J. M. Dean

With the continued downward pressure on coal selling prices, mine management must make its operations as efficient as possible. The problem is the same one throughout the mineral industries, streamlining operations to maintain competitive mining costs (Born, 1991). There has been a great deal of research into better using production manpower. But the story is different for operations support personnel. Traditionally, planning man-power requirements are done annually, with modifications to the operating plan occurring generally quarterly. On the other hand, the demands on manpower are often dynamic, being responsive to changing productivity levels ,mine conditions (including water influx, bad roof, poor floor)and unanticipated project requirements (responses to machine breakdowns or a new section setup requirement because of a drop in coal quality in another area). Such changes may impact the manpower structure significantly. At times they may cause serious labor relations problems concurrently. Realignments and the generation of instability in the workforce because of active job switching (bidding) are a result. Most responses by coal operators are reactive rather than proactive, a situation that could be mollified by more accurate and detailed planning of predictable manpower requirements. A manpower planning tool is needed that takes into consideration such things as changing productivity levels and conditions as manhour requirements for different work areas are planned, rather than blindly allocated through traditional staffing modes.

Jan 1, 1995

By Ronald J. Riberich

The Mineral Economics and Management Society (MEMS) held its fifth annual conference in Montreal, Quebec, Canada earlier this year. “The Minerals Industry: Responding to the Global Challenge” was the first MEMS conference to be held outside of the United States. About 125 mining- and minerals-related professionals attended. The MEMS program included six sessions and three distinguished speaker addresses. The session topics included: “Minerals in the Macro economy: Development in Demand,” “Trends in Global Metals Supply: The Producers’ Challenge,” “Global Environmental Issues: Policy Perspectives,” “Global Environmental Issues: Quantitative Analysis” and “Minerals in the CIS: Phoenix or Albatross?” A student session was also offered. It provided a competition for monetary awards for outstanding papers.

Jan 1, 1996

Conventional wisdom in the mineral processing industry leads one to believe that pressure oxidation of refractory carbonaceous (preg-robbing) ores is not a practical approach to process development. Initial acid pressure oxidation testing on carbonaceous sulfide ores at the Twin Creeks Mine supported this conventional wisdom. After testing other refractory process options, including air and oxygen enriched roasting, Santa Fe Pacific Gold decided to take a second look at pressure oxidation, using conditions outside the normal range of conventional practice. A combination of very fine grinding and high operating temperature and pressure resulted in significant increases in gold extraction. This paper details the effect of operating parameters developed for Twin Creeks on gold recovery, sulfur oxidation, carbon oxidation/passivation and preg-robb through the laboratory and pilot plant investigations.

Jan 1, 1995

By James K. Wright

This chapter will discuss the use of financial models as an evaluation tool for various phases of decision making from exploration strategy to the analysis of a producing mine. The text of this chapter was not received in time for printing.

Jan 1, 1979

By Andreas Eberhorn

The evaluation criteria for cost comparison of the Gearless Drive, also called Ringmotor or wrap-around motor, as variable-speed drive with a Twin Drive System using synchronous motors are reviewed. Both mechanical and electrical components of the drive system are considered. The evaluation criteria are described and for the cost comparison the applicable method is demonstrated. The cost comparison is based on a medium and large sized mill system. Each drive package will display cost details with regard to capital cost, maintenance, power losses, overall efficiency, overhead and loss of production. As conclusion the benefits and disadvantages of the two drive/mill packages will be presented together with a payback diagram.

Jan 1, 1996

By Donald W. Gentry

This paper presents some of the results of a rock mechanics in¬strumentation program designed for, and implemented at, longwall panel 4N at the York Canyon Mine near Raton, New Mexico. The objective of this particular instrumentation program was to determine the response of the rock mass to longwall mining of a thick coal seam utilizing shield-type supports. Measurements were made in the rock along the ground surface, above the coal seam, in the coal seam and immediately below the coal seam. Longwall test panel 411 had a total developed length of 762 m (2500 ft) and a face width of 168 m (550 ft). The seam mining height in the panel area was approximately 3 m (10 ft). The average depth of overburden above the panel is 107 m (350 ft) al¬though it ranges from 73-134 m (240 - 440 ft). Roof support at the face was provided by Hemscheidt shields. These shield-type supports weigh 11.4 metric tons each.

Jan 1, 1977

By C. V. Deutsch, O. Babak

A longstanding problem in geostatistics is that kriging usually assigns significantly greater weights to end samples in strings of data than it does to central samples. These weights are theoretically valid, but suboptimal estimates may result when there are geological trends in the variable near contacts, that is, large weights may be applied to samples that are systematically lower or higher than average. A number of ad-hoc corrections exist, each with pros and cons; none are fully automatic with a well-defined measure of optimality. A new method for estimation in a finite domain is proposed. This method is referred to as finite domain kriging. The method is based on kriging with a successively larger number of data. The total number of relevant data (n) is established, and then n kriging matrices are solved. The first matrix has the closest single data value (n-1 weights are set to zero); the second has the two closest data (n-2 weights are set to zero) and so on. The final matrix has all n data. The kriging weights used for estimation are the average of the weights from the n successive kriging runs. Each kriging run is optimal, yet with different smoothing and a different treatment of data at the end of the strings. The result is a set of weights that does not give undue influence to data values at the end of strings. The methodology is developed with examples. Cross validation shows that finite domain kriging outperforms conventional kriging.

Jan 1, 2009

By James C. Hower, B. K. Parekh

Introduction The purpose of coal preparation is to improve the quality of coal to make it suitable for a specific purpose by (1) cleaning to remove inorganic impurities; (2) sizing-crushing or screening, or both; and (3) special treatment, such as dedusting. The properties and quantities of impurities in coal are of major importance in the design and operation of steam generating equipment. Although boilers are often designed and equipped to use a wide range of coals, no boiler will perform equally well with all types of coals. All coals have certain properties that place limitations on their most advantageous use. These limitations are especially stringent for many of the older installations. Because of a general lowering of quality of raw coal in recent years, the need for coal cleaning has significantly increased. Among the factors contributing to the need for increased coal preparation are (1) increased demand for quality brought on by market and environmental requirements; (2) increased extraneous dilution caused by mine, health, and safety laws; and (3) depletion of the higher-quality coal seams. The major characteristics of coal and impurities from the standpoint of mechanical cleaning are particle size composition, generally called size consist; density differences; the relative friability of the coal and its associated impurities; hardness; and strength. Some of the other factors related to preparation are petrographic composition and rank. RANK CLASSIFICATION Coal is a general designation for a great number of solid organic minerals with different compositions and properties; all are rather rich in carbon and have a dark color, generally black. Next to mineral oil and kerogen, coal is the most important reservoir of carbon in the world. Carbon is an indispensable necessity of life as well as the main source of energy. Coals are found in stratified deposits, sometimes at great depths. All coals owe their origins to slow decomposition and chemical conversion of immense masses of organic material. As found in seams, coal is a heterogeneous mixture of organic and inorganic materials. Not only are there large differences in the properties of coal originating from different seams, but also in coal removed from different locations in a single seam. A genetic relationship exists between peats, brown coals, lignites, biturninous coals, and anthracites. As a whole, the process of coal formation, or coalification, proceeds as a continuous transformation of plant material, each phase characterized by a degree of coalification, or rank. As a measure of this rank, the carbon content or some related parameter can be used.

Jan 1, 1991

By J. F. T. Agapito, L. J. Gilbride

High horizontal stresses were recognized to impact roof stability more than 60 years ago. Since then, numerous measurements associated high horizontal stresses with difficult ground conditions. This paper presents case histories illustrating the practical usage of roof stress determinations for helping assess stability, not only in the case of high horizontal stresses but also of low stresses. Examples are given of high stresses associated with faults, mine design changes, quantification of stress shadow effect, and anistrophy. The paper concludes with a comparative evaluation on the effect of various stress fields on ground support requirements.

Jan 1, 2002

By Robert A. Blake

Introduction Sulfide copper, zinc and iron concentrates are recovered in the 5000 ton per day flotation plant operated by Cities Service Company at Copperhill, Tennessee. The heavy-sulphide ore is first ground to 50 pct. minus 200 mesh and a bulk concentrate floated. The bulk concentrate, over 60 pct. of the ore weight, is reground to 72 pct. minus 200 mesh and then treated in a selective flotation circuit to recover copper and zinc concentrates. The tailing of selective float is the iron sulphide material source for the manufacture of sulfuric acid and iron sinter. The valuable minerals in the ore are chalcopyrite, marmatitic sphalerite, pyrite, and pyrrhotite. A typical mineralogical analysis will be found in table 1. A typical material flowsheet will be found in figure 1. Shown in the flowsheet are a scavenger float on the bulk rougher tailing and a copper-talc separation unit. At times a lead-copper separation circuit has been run.

Jan 1, 1971

By G. Heinrichs

This paper is intended to provide information for one to be able to determine the slurry system head curve for pump applications. The slurry characteristics are the basis for what the size, material of construction, and critical carrying velocity of the pipe will be. The system head curve is adjusted by use of the pipe friction coefficient factor and slurry derate factors. An example using multi-staging of slurry pump curves is presented to compare the wear life relationship of pump parts for a tailing pipeline system head curve.

Jan 1, 1996

By J. W. T. Ropkins, D. Allenby

The paper describes a technique by which large concrete boxes are unobtrusively inserted beneath existing highway and railway infrastructure to form new subways, culverts and under-bridges, thus avoiding the inconvenience and costs of disruption to traffic associated with traditional cut and cover techniques. A series of project examples, undertaken in the United Kingdom and United States, are used to illustrate the design and construction of the box structures, together with the technology required to control ground disturbance in the tunnel face and around the box, and the jacking systems necessary for box installation.

Jan 1, 2003

By Kadri Dagdelen, Steven Hoerger

For gold mines, orebody uncertainty is one of the leading causes of differences between planned and actual production. Geostatistical conditional simulations create multiple equally probable orebody block model realizations which are conditional to the current drilling information and demonstrate the sampled grade distributions and spatial statistics. These simulated block models are key inputs for a stochastic evaluation to show the likely range of grades and cash flows to be delivered by a mine plan. The stochastic evaluation outputs can be used to compare different mine plans in terms of expected values and risks to planned grades, production, costs, Net Present Value (NPV) and other plan metrics. For the McLaughlin gold mine, risk profiles are demonstrated to show how different mine, cut-off and stockpile strategies can reduce risk and improve expected value. The strategies considered were effective in improving expected NPV and reducing or eliminating tonnage uncertainty, but the strategies had little impact on reducing the uncertainty of NPV’s or mill grades. The stochastic evaluation process is also used to compare the risk impact of orebody uncertainty against the risk of not achieving planned mining tonnages or vertical advance rates. Risks for plans created with and without stochastic mine plan optimization are also compared.

Feb 1, 2025

By H. Sevim

In this paper, the research effort in simulating the operation of underground coarse-coal hydrotransport systems (UCCHS) is summarized. The equipment of the system to be simulated is already optimally selected by using an analytical optimization model. The purpose of the simulation model is to test the performance of the system and to obtain the distribution of the operating parameters such as water and power consumption, amount of slurry delivered to the preparation plant, etc. Knowledge of the distribution of these parameters is essential for the efficiency of the design and the operation of the system.

Jan 1, 1985