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By B. Hagemeyer

The trend to higher solids paper coating and to neutral/alkaline papermaking is causing an above average growth in the use of calcium carbonate as both a paper coating and a paper filling pigment. These developments are expected to continue well into the 1990s. Thus, calcium carbonate will account for a somewhat larger percentage of total paper pigment volume. Nevertheless, overall growth in paper tonnage coupled with an increase in filler pigment percentages will create a demand for larger quantities of other pigments as well. Kaolin will continue to be the dominant paper pigment by far, with continued growth though at a somewhat slower rate than calcium carbonate.

Jan 1, 1986

By J. M. Mutmansky

This paper outlines the results of a study of the opinions of practicing engineers concerning the value of environmental engineering courses in a mining engineering curriculum. One hundred engineers with significant experience in mining-related engineering work were carefully chosen. Of the 67 responses, about half were from mining engineers, and the other half were from environmental engineers. In this paper, the results of the survey are outlined. The number and type of courses recommended by the respondents are summarized as well as the specific topics recommended for inclusion in a mining engineering curriculum. The survey form also asked for the stages in the mine life when environmental experts were needed and the percentage of environmental engineering performed by outside experts for many mining-related environmental tasks. The results of this line of questions are provided. Finally, the paper offers a comparison of the results for environmental engineers and mining engineers and analyzes the differences.

Jan 1, 2003

By N. S. Tanious

This paper summarizes results from an investigation into possibly the largest coal pillar failure in the USA. The newly opened coal mine worked an 3.35 m (11 ft) seam under overburden depth that ranged from 91 to 671m (300 to 2200 ft) . The mine main entries, and the enclosed pillars, experienced a massive slow squeeze. The squeeze could not be controlled and the mains were lost. A new set of mains were driven. Entry convergence (closure) measurements were carried out behind the advancing face to monitor stability. Pillar stresses were also measured under four different depths of overburden: 229.433, 472.579 m (750,1420,1550, and 1900 ft). The strength of pillars in the new mains was calculated from the loads that triggered the failure in the old mains, using three pillar strength formulas. The stress measurements showed that the new pillars supported more load than their predicted strength, indicating that current strength formulas are inadequate under deep conditions.

Jan 1, 1992

By Surendra K. Mishra

Metallic and oily components are the major contaminants of industrial wastes. Underground burial and incineration have been the commonly practiced methods of waste management. To provide a relatively more permanent solution, different processes have been developed. In addition to reviewing these processes, potential of using flotation as a process to treat hazardous metal and oil contaminated wastes is discussed in this paper.

Jan 1, 1989

By Gordon I. McPhail, John D. Nelson

Tailings management represents a major portion of the cost associated with extraction of gold. For each gram of gold extracted, 150 to 200 kg of waste material is produced. Because of environmental concerns and unwillingness of society to accept environmental damage caused by poor waste management practices it has become essential to follow responsible and safe practices in tailings management. This paper presents general aspects of tailings management and discusses different techniques utilized. Characteristics of tailings and the effects that these have on stability and environmental aspects are discussed. The paper also discusses the effect of mine back-filling practices on the surface disposal of the remaining tailings fraction.

Jan 1, 1987

By John Matthews

During 1982 and 1983, it became increasingly clear that North River No. 1 Mine would have to buy a set of replacement longwall shields. Despite extensive efforts to make improvements, the shields that were in place at that time were incapable of holding the roof. North River Energy had limited experience in specifying and acquiring longwall roof supports, but a great deal of experience with our conditions and needs. We there- fore compiled a shield evaluation method that uniquely responded to our situation. The resulting system emphasized teamwork among operating, maintenance and engineering personnel. The charge from management was threefold: select shields to support maximum expected loads, optimize face operations, and pay attention to detail. Final selection was made objectively, based on all available information. We chose a 5516 KN (620 tons) support with a minimum yield load density of 760 KN/m2 (7.9 tons/ft2). This paper reviews our process of specification, design, prototype testing, and fabrication, and offers some relevant suggestions.

Jan 1, 1986

Diamond wire rock cutting is the most widely used technology in carbonate stone quarrying owing to technical performance and block face quality. Interest is also growing for siliceous deposits. This paper deals with the problem of optimum wire utilization under restrictions regarding a set of variables and parameters. A computer program of general applicability has been set up with the aim of studying the most suitable combination of technologies and the effect on the technical and economic results of bench geometry, overall quarry yield, market -stone value, quarry size as well as the quantity, productivity and price of human and material resources and their organization in the elemental working cycle. Two quarrying problems are considered as significant instances a granite and a travertine quarry. The results are illustrated and discussed.

Jan 1, 1989

By Fabio Amaya, Andrés Marulanda, Ramiro Gutiérrez, Alberto Marulanda

The behavior of a salt rock mass is strongly related to a creep phenomenon. The amount of creep depends on the level of stress generated in the underground excavation. Additionally, security conditions and the lifespan of an underground cavern excavated under this geological conditions depend on the evolution of creep. Based on the experience of the failure of the Old Underground Salt Cathedral of Zipaquirá(Colombia) and the construction of the new one, the theoretical framework to predict the creep behavior of a salt rock mass is explained. The theoretical formulations are calibrated based on actual observations of the material behavior to predict the lifespan of this striking structure.

Jan 1, 2003

By J. Felipe Costa, Andrew H. White, Marcot T. M. B. Vilhena

Ordinary kriiing (OK) is an interpolation algorithm mostly used in earth sciences applications where it provides satisfactory results. Robust kriging (RK) is an alternative algorithm which at- tempts to minimise the problems caused by the existence of outlier values within a given data set. Robust kriging essentially consists of an editing step prior to running the traditional OK method. This study compares the interpolation results obtained by OK and RK. Two data sets were used. The first data set consists of 140 samples mimicking a drilling survey named cluster.dat. An additional feature of this sample data is that its parent population, the reference data set, is available, thus permitting direct quantitative assessment of the effectiveness of a given estimation technique. The second data set consists of a grid sampled at 1x1 m. The estimates obtained by OK and RK using cluster.dat were compared to the reference data set. RK provided better results in terms of quality of the estimates than OK

Jan 1, 1996

By Harrison R. Cooper

Composition data is needed as input for executing process control and management of particulate separation for flotation control. While requirements for composition data can be satisfied in many cases by manual sampling and analysis, automatic sampling and assay systems are now viewed as justified for all but the simplest or smallest processes. On-stream X-ray fluorescence analysis (XRFA) has satisfied requirements for the main portion of metalliferous sulfide ore flotation processes as XRFA technology evolved in reliability and sophistication from its beginnings in the late 1950's. In recent years, advanced on-stream analysis technologies have reached levels of development suitable for use in process control to increase efficiencies of important processes in mining and minerals industries such as coal fines flotation and industrial minerals beneficiation (particularly phosphate beneficiation) where XRFA methods have been inapplicable. Recent technical developments pertinent to use of advanced technologies as well as improvements to established on-stream composition analysis methods are discussed.

Jan 1, 1989

By P. L. Padgett, J. C. Hower

Five coals blended at a Midwestern United States power station were subjected to detailed analysis of their Hardgrove grindability. The coals, representing four distinct coal beds, are a low-sulfur, high-volatile A bituminous Upper Elkhorn No. 3 coal (Pike County, Kentucky); a medium-sulfur, high-volatile A bituminous Pittsburgh coal (southwestern Pennsylvania); a low-sulfur, subbituminous coal from the northern Powder River Basin (Montana); and two low-sulfur, subbituminous Wyodak coals from two different mines located in the eastern Powder River Basin (Campbell County, Wyoming). All samples that were processed in the Hardgrove grindability tests were also analyzed for their maceral and microlithotype content. The high-vitrinite Pittsburgh coal and the relatively petrographically complex Upper Elkhorn No. 3 coal exhibited different grindability behavior. The petrographic compositions of the Pittsburgh raw feed, the 16 x 30-mesh fraction (HG! test fraction) and the -30-mesh fraction (HGI test reject) are similar, suggesting that the HGI test fraction typifies the whole feed. The eastern Kentucky test sample is not as representative of the whole feed, with the HGI test fraction having lower vitrinite amounts than the rejected -30-mesh fraction. The Powder River Basin coals are high in vitrinite content and show behavior similar to the Pittsburgh coal.

Jan 1, 1998

By D. E. Munson, T. M. Torres, D. A. Blankenship

The Thermal/Structural Interactions (TSI) In Situ Tests are a series of large scale, well instrumented tests that have been constructed at the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. As a precursor to the TSI tests, a ventilation drift (Room D) was mined, drilled and instrumented. This room provided the contractor an excellent area to practice controlled construction methods and was a proving ground for construction monitoring and documentation methods. All gages in this first room have been monitored since their initial installation, which has provided a small, but representative, data base. These data also were the first to be available from any TSI area for analysis. This paper discusses the construction activities in Room D and the data generated from the construction and drilling. Deformation of the room is compared briefly to numerical calculations that used a rather simple creep model as a reference. The constitutive model for salt, it appears, must be improved before it can predict the underground deformations.

Jan 1, 1986

By S. Chander

Neutralization of acidity by addition of alkaline materials is a commonly used method to treat acid mine drainage. However, this procedure requires large amounts of reagents based on acid-base accounting. The potential use of organic additives in preventing or ameliorating acid mine drainage was investigated in this research. The tests were conducted in weathering columns using refuse samples from a coal cleaning plant. Both cationic and anionic compounds were tested. For a comparison, tests were made in the presence of limestone and lime. The results show that some of the reagents substantially retarded the rate of oxidation whereas others even enhanced it. The suppression of the rate of pyrite oxidation was ascribed to surface chelation. Formation of surface compounds prevented the pyrite particles from further oxidation. Such a treatment required only small quantities of reagents since the reaction was confined to the surface.

Jan 1, 1992

Traditionally, production volume has been considered the major determinant of cost. As volume increases, total cost increases but unit cost decreases. This concept has been so widespread in industry that many of the tools used to analyze costs are based on production volume as the sole measure of activity and driver of unit cost-fixed and variable costs, cost-volume-price and breakeven analysis, contribution margin, flexible budgets, and others. Clearly, volume is a driver of cost. It is important in both a tactical sense (to the manager at an operating mine) and a strategic sense (as one determinant to the firm's overall cost position). However, many other factors influence costs as well, even though they have not been studied to the same extent. For example, production managers know that their costs will be reduced if the workforce does not have accidents. Safety costs are to a large extent independent of volume. Other cost components increase as volume increases, such as some environmental charges. Some costs may or may not reflect volume changes. Maintenance, for example, may appear as either a fixed or variable cost, as can operating labor in facilities that are highly automated. In the strategic sense, where the firm is selecting a strategy to pursue competitive advantage and increased profitability, all costs are variable. This reflects both the strategic intent and the long-term time frame associated with strategic positioning. Tactically, on a month-by-month basis, some costs are essentially fixed. Cost driver analysis must therefore consider the relevant time frame.

Jan 1, 1999

By T. Cohen

Technological innovation in the minerals industry must be driven by the need to improve performance according to social, as well as environmental, safety, efficiency and production criteria. This paper outlines the possibilities and rationale for incorporating constructive technology assessment into technology research and development within the CSIRO Minerals Down Under National Research Flagship (MDU). The paper develops a process of Social License in Design that attempts to address the future social challenges and opportunities of a technology during development by utilising forecasting techniques and accounting for the perspectives and values of decision makers and likely stakeholders. Interviews with senior technologists and social scientists within MDU reveal the institutional context into which the Social License in Design process is to be situated and highlight key factors that may inhibit or enhance its uptake.

Jan 1, 2011

By J. M. Schisler

In the last five years Eldorado Resources Ltd. (ERL) has undergone a major expansion and modernization of its uranium refining and conversion plants. A new refinery for processing yellow cake to UO3 was constructed at Blind River in northern Ontario and started up in 1985. Its rated capacity is 18,000 t/a uranium as UO3. At Port Hope, Ontario, ERL's new UF6 conversion plant has been constructed. This plant started up in 1984. It utilizes the novel, wet-way process to produce UF4 and gives the company a UF6 production capacity of 14,500 t/a U. Also at Port Hope is Eldorado's ceramic UO2 powder production facility, commissioned in late 1980. It has a capacity of 1700 t/a uranium as UO8. With the completion of these capital projects, Eldorado has the largest and most up-to-date refining and conversion facilities in the western world. This paper reviews the refining process and process design. The methodology used to start up the Blind River plant is described as are some startup difficulties, solutions that were developed, and the resultant current operation.

Jan 1, 1987

By Leonid P. Ni, Askar M. Kunayev

It is well known that processing of the high-silicon bauxites for obtaining alumina by the hydrochemical Bayer process is irrational due to the significant losses of alumina and alkali with red mud. The main source of losses of the mentioned compounds under the conditions of leaching by the Bayer process is the formation of difficultly soluble sodium alumosilicate of the composition Na20 .Al203, 2Si02 . n H20. A conventional method of an extra recovery of alumina as well as of regeneration of alkali out of red mud is the high-temperature sintering of the latter with soda and limestone with the subsequent leaching of sodium aluminate from the sinter by water or soda solution. A sequential version of the Bayer-sintering flow chart recommended for the prosessing of bauxites with an increased content of silica is based on this method. However, the sintering method is not the only alkaline method allowing to make an extra recovery of alumina likewise of alkali from red mud. Our investigations showed/I/, that the components mentioned can be recovered by a pure hydrochemical method of treating red mud with concentrated alkaline solutions, with lime (Ca0) being present, that was earlier succesfully used in the development of the hydrochemical method of processing nepheline rocks/2/. The possibility of extracting alumina and alkali from red mud is based on the reactions which can be schematically represented in the following way:

Jan 1, 1984

By R. C. Bryan, D. B. Jamison

This paper describes a procedure for minimizing the operational costs associated with blending sodium in coal at a surface mine in the Powder River Basin. Mine site blending is performed by adjusting daily production rates for high- and low-sodium pits. These adjustments are designed to produce a consistent sodium value called the blending target. The mine's contractual limit for sodium is sufficiently close to the field average value that any decrease in the sodium blending target may result in an opportunity cost, if the number of potentially minable tons is reduced. Conversely, any increase in the blending target may result in a higher sampling cost if more information is required to keep the blend within contractual limits. Blending parameters were defined using a geostatistical block model of sodium content that was based on analyses of hundreds of in-pit sample holes. Variograms for these data were used to compute the marginal costs of opportunity and sampling for a series of hypothetical in-pit drilling patterns. These marginal costs provided a basis for selecting optimum values for key parameters such as the blending target, production variance and in-pit sampling density. The benefit of implementing these optimized parameter values is that operational costs of sodium blending will be minimized over the long-term. At the mine where this procedure was developed, each dollar spent to increase the sampling density to the optimum value was shown to generate a $10 savings in opportunity cost.

Jan 1, 1991

By I. Ehie, Y. P. Chugh

Physical mine modeling and computer simulation techniques were used to conduct technical feasibility and economic analyses of selected pit configurations for surface mining a single coal seam dipping at about 15% to a maximum depth of 46 m (150 ft). Pit orientations along the true dip (dipline), along the strike (strikeline), and along an apparent dip were studied. Physical models of each pit configuration were prepared first to delineate potential operational problem areas and also to furnish data for the computer simulation models. A dragline microsimulation, a shovel/truck simulation, and a surface mine cost analysis models were used to conduct the study. Sensitivity analyses were conducted on variables such as the pit width, block length, and seam pitch. The productivity (m3/h) of the mining equipment (dragline or stripping shovel) under each set of conditions was used to optimize the pit configuration. Both block length and panel width were found to significantly affect the dragline productivity. Larger size trucks were preferable to smaller size trucks in the pit con¬figuration along an apparent dip. The cost analysis results showed that the pit configuration along the seam dip was more economical than the pit along the strike or along an apparent dip for the mining condition studied.

Jan 1, 1987

By V. T. McLemore

The Steeple Rock district in New Mexico is a major epithermal gold-silver district that exhibits district zoning. Five types of ore deposits occur within the district: •base-metal veins (with gold and silver) form the center of the district and occur along the Carlisle fault, •gold-silver veins along northwest-trending faults and outward from the base-metal veins, •copper-silver veins along the margins of the district, •fluorite veins along the margins of the district, and •manganese veins along the margins of the district. Areas of older acid-sulfate alteration occur throughout the district and also exhibit the following zoning: massive silica/chert zone (inner), silicified zone and clay zone (outer). This alteration overlies regional alkali-chloride (propylitic to argillic to sericitic) alteration. Synthesis of available data suggests the acid-sulfate alteration is related to a shallow, but older, epithermal hot-springs system. Subsequently, younger epithermal veins formed along faults.

Jan 1, 1996