Search Documents

By Donald E. Ranta

Many portions of the mining industry are under intense pressure to reduce costs while commodity prices languish. In response, global Internet-based marketplaces to deliver business-to-business (B2B) e-commerce solutions are being established to reduce costs and improve efficiencies across the mining industry supply chain as well as with customers. Over time these marketplaces will likely evolve to create an integrated supply chain solution, layer in value-added services, and develop mining community portals with industry content. Significant opportunities to help reduce costs and create value are available in mining e-procurement as well as in on-line product sales. The supply chain for the industry is highly fragmented and many mining companies have numerous inefficiencies in procurement. An e-procurement marketplace (or "exchange") can immediately address these inefficiencies and offer numerous benefits to buyers and suppliers. These benefits include improved sourcing options, inventory cost reduction, transaction cost reduction, access to value-added services, lower customer and supplier acquisition costs, improved reach, and improved information flows.

Jan 1, 2001

By Robert F. Randolph

New technologies confront mining organizations with unprecedented human factors challenges. Likely problem areas range from the design of the human- machine interface to the design of work groups and mine organizational structures. However, these human design considerations are commonly ignored in most industries, resulting in a failure rate of 75% for advanced technology programs. The U.S. Bureau of Mines is addressing these concerns through a program of research on the human side of high technology mining systems. Interviews with mining industry participants and researchers have identified concern in several areas, including training and equipment design. Although new mining technologies promise to improve overall safety by relocating miners away from hazardous areas, data from MHSA accident reports and other sources suggest that certain types of new hazards may be created. Many of these new hazards can be reduced though a systems approach to ergonomic design of equipment, tasks, and work processes. This evidence, combined with reviews of high technology human-machine systems in other industries. can help in the design of safe and efficient future mining technologies.

Jan 1, 1992

By Stanislaw Nawrat, Waclaw Trutwin, Waclaw Dziurznski, Janusz Roszkowski

In recent years attempts have been made to fight open and intensive mine fires by the use of special extinguishers, which are able to produce great volumes of inert gases directed into the fire zone. These extinguishers are derived from turbo-jet engines used in aircrafts and adopted for operations in mine conditions. The purpose of this paper is to draw the attention to a computer simulation method, enabling studies of dynamical behaviour of mine ventilation processes disturbed by open fires, which are also influenced by measures taken during fire fighting actions i.a. the mentioned operating extinguishers. The first part of this paper gives an account of the principles on which the computer simulation program, concerning the non- steady mine ventilation process, the fire as a heat source and the extinguisher as a source of inert gas and moisture has been based. The next part of this paper deals with simplifying assumptions and the subsequent limitations of the derived simulation pro- gram. Finally, from an example of a computer simulation, the results will be presented and relations shown between parameters characterising the ventilation process during the fire fighting action.

Jan 1, 1997

By Robert K. Towner, Francis S. Kendorski

Shotcrete drift linings at the Climax Mine of the Climax Molybdenum Company have undergone four years of extensive evaluations as a replacement for thick poured-in-place concrete linings. Any drift lining at Climax must be able to withstand the rigors of undercut and secondary blasting, weight problems induced by panel caving, and the abrasion of slusher mining. Examined here are the conclusions reached so far on shotcrete drift linings which have not yet completed the approximately six-year cycle from development to ore exhaustion. Properly applied shotcrete is an adequate drift lining for all phases of the Climax panel caving system of mining. Undercut blasting will damage shotcrete unless blasts are correctly timed. Weight problems will destroy shotcrete drift linings as efficiently as it will destroy concrete or steel support systems. Abrasion and secondary blasting results are inconclusive as the shotcrete lined slusher drifts have not entered the ore production stage of the mining cycle. In addition to drift linings, Climax has found shotcrete to be invaluable for lining large underground shops, for temporary support systems, for permanent ventilation bulkheads and for the repair of abraded or weight damage concrete lined slusher and haulage drifts.

Jan 1, 1974

By D. M. Wyslouzil

Conditioning, in the conventional sense, means providing sufficient agitation and contact time for the reagents to react with the minerals in the ground ore. High intensity conditioning (HIC) on the other hand, as described in this paper, recognizes the need to exceed this minimum power input over a suitable length of time to induce aggregation of the finest size fraction. Time alone is not sufficient to achieve aggregation. The threshold minimum power input, kW/m3, depends on many surface properties of the fine particles and can vary considerably. In addition, the mechanical aspects and the chemical conditions must be matched to achieve good aggregation. Treatment of complex sulphide ores, requiring fine grinding for liberation, offers a large field for the application of HIC. Improved flotation rates and enhanced selectivity are some of the benefits that can be expected. This unit operation has now reached the level of commercial application. Lakefield Research considered HIC not from a fundamental point of view but as a means of solving difficult mineral processing situations arising in actual operating plants. This paper summarizes the effects of the various chemical reagent combinations that had been applied to promote faster, more selective flotation, higher mineral recoveries and cleaner separations, using HIC.

Jan 1, 1995

By R. V. Ramani, S. Tan

In this paper, several commonly used computer truck-dispatching criteria are evaluated. A computer-oriented truck-dispatching and production simulator was developed to provide data for comprehensive cross comparison among the dispatching criteria. The definitions, primary considerations, characteristics and performances of these dispatching criteria were investigated. From the simulation results, it was concluded that, in general, no one criterion can dominate all others. However, several dispatching criteria that have good potential to increase performance can be identified. All basic dispatching criteria, including minimizing truck waiting time, waiting shovel with minimum waiting time, minimizing truck saturation, maximizing truck momentary productivity or optimization of truck routes, provide local optimal solutions. To obtain a direct global optimization solution for this complex stochastic process does not appear to be likely Therefore, the search for an optimal dispatching criterion that will fit all conditions may not be realistic. It may be necessary to search for a hybrid combination of the several truck dispatching criteria that have good potential for a given situation. An approach to selecting such a hybrid dispatching criterion is presented.

Jan 1, 1993

By N. R. Billette

In 1982 and 1983, a study was undertaken to analyse the applicability of Elbrond?s analytical model to suit the needs of Lake Asbestos of Quebec in their computerized open pit planning and scheduling strategy. The immediate goal was the assessment of the optimal allocation of trucks and the determination of the extra cost of in-pit blending. Data from 45 tonne trucks was used to estimate the mine capacity based on a fixed assignment policy. The tonnage yielded by the analytical model was compared with the results of a simulation program. Another point that the study high- lighted was the definition of efficiency parameters for the haulage system: shovels-trucks-crusher. The efficiency, both of the utilization of financial resources and of the operations, for the overall system reaches optimal values in very precise conditions for the number of pieces of equipment in operation. Such a parameter is proposed as a standard for the definition of an optimal number of trucks and shovels in operation. Deviations from this optimum do occur in a well-planned system for qualitative goals. These can then be quantified in terms of costs to the mining company.

Jan 1, 1986

By W. Morgan, D. Gove

In truck and shovel operations, productivity and cost per ton are influenced by the system matching choice, Optimization involves a balance of the size and number of trucks, the size and type of loading tool and the projected material conditions and haul roads. Caterpillar has updated its Fleet Production and Cost program so miners can more easily look at matching choices and optimize on the variable they choose. This paper introduces the Fleet Production and Cost program. It then demonstrates its capabilities with examples of optimization. Mining operations that use trucks need to properly match the number and size of hauling units (trucks, wagons, scrapers, etc.) to a loading unit (wheel-loader, hydraulic shovel-excavator, cable shovel, push tractor, etc.) to provide the best possible fleet match. Optimizing fleet match minimizes the cost per unit of material moved by that fleet. As haul conditions change (haul length, grade or rolling resistance), there may be need to adjust the number of trucks to maintain the optimum fleet match. Fleet Production and Cost is a tool that can be used to optimize the truck-loader match.

Jan 1, 1995

By I. Iwasaki

As the world tension relaxes and as the interest and taste for consumer products change, complacency is beginning to prevail over the needs of minerals and primary metals. The current trend towards resources and energy conservation calls for miniaturization of consumer goods, and lowers the demand for virgin materials to produce goods and services. Challenged by the third world countries with high grade ores and low labor costs, industrialized nations with lower grade ores are being pressed into more efficient operation through technological innovation, while protecting the environment. In many countries, domestic mines were forced to close since the oil crises due to rapidly rising energy and labor costs. Research in conventional mineral processing needs to be directed towards breakthrough technologies in order to maintain the competitive edge in the global marketplace. Research activities will provide new challenges in the processing of solid waste and waste water for environmental remediation as well as for resource conservation, in the preparation of new functional materials of extreme purity and/or unique properties for high technology applications and in the development of such future resources as deep sea minerals and extraterrestrial materials.

Jan 1, 1995

By A. E. Hall

INTRODUCTION Underground gold mining operations are found in South Africa, U.S.S.R., Canada, the United States, Zimbabwe, Ghana , Brazil. Australia, China and many other countries. The methods used for extraction differ from highly mechanized trackless mining in the developed countries to the labour intensive systems of the third world nations. The climatic conditions in which mines are situated vary from equatorial to arctic. The rock temperatures and the depth of workings also vary significantly from shallow to extreme depth. The Western Deep Levels mine in South Africa is the deepest and exceeds 4.000 metres in depth with strata temperatures above 55°C. These major differences between mining fields result in significantly different ventilation problems in underground gold mines. The ore types also vary and some deposits have high silica contents while other mines extract sulphide ores. Methane may also be encountered in underground gold mines and can have a large influence on the ventilation practice. Several topics are currently of concern to operating mines and are reviewed here:- a) Air circulation and fans b) Mine cooling c) Permafrost operations d) Mine heating e) Control of diesel exhaust f) Gases, fires and explosions

Jan 1, 1988

By M. R. Peterson, C. R. Ferguson, T. H. Jeffers

The ability of microorganisms such as yeast, bacteria, and various aquatic flora to sorb metals from dilute aqueous solutions is well documented. Although microorganisms have significant potential in decontaminating waste waters, techniques and equipment suitable for bioassisted decontamination are limited. The Bureau of Mines has investigated the use of microorganisms immobilized in porous polysulfone beads for extracting toxic and heavy metals from dilute waste streams. The minus 8- plus 12-mesh beads were fabricated from high-density poly- sulfone dissolved in dimethylformamide (DMF). Dried, thermally killed yeast, algae, duckweed, xanthan gum, and alginates were blended into the polysulfone-DMF, and spherical beads were formed by injecting the mixture into water. Microscopic analysis revealed microorganisms immobilized within the bead pores. The beads had excellent handling characteristics and were tested in stirred reactors, fixed bed columns, and fluidized bed columns for their ability to remove metal contaminants from several waste waters. The effluents resulting from these waste waters met or exceeded the National Drinking Water Standards for cadmium, copper, manganese, and zinc. Other heavy metal contaminants readily sorbed by the beads included arsenic and mercury. Elution of metal values from the beads was accomplished using dilute nitric acid or sodium carbonate.

Jan 1, 1989

By L. M. Chan, D. H. Carlson, J. H. Johnson

This paper discusses laboratory evaluation of a tailpipe emissions measurement apparatus (EMA) developed by Michigan Technological University (MTU) under contract to the Bureau of Mines. The apparatus dilutes diesel exhaust and measures the concentrations of diesel particulate matter (DPM), CO, C02, NO and NO2 at known dilution ratios. The EMA was evaluated by side-by-side comparison of its measurements with those by laboratory grade instruments. During the preliminary laboratory evaluation concentrations of DPM, CO and CO2 were measured. The concentrations of CO and CO2 measured by the EMA were usually within ±14 pct of laboratory-measured values for CO and ±20 pct for CO2. EMA DPM concentrations correlated well (r = 0.96) with the laboratory values, but were 29 pct lower on average. The CO and C02 differences were observed to be related to the method of calculating the EMAs' dilution ratio and the difference in DPM concentrations is attributed to thermophoretic and/or condensation losses related to the EMA's unheated sample probe. Preliminery analysis of data obtained with a heated sampling probe and modifications in the sampling procedures have indicated reduced variability in DPM and in the calculated dilution ratios.

Jan 1, 1991

By R. L. Garrett

The quality of mineral additives used in a drilling fluid (mud) can dramatically affect the fluid's properties and the overall cost of drilling an oil or gas well. The principally wed minerals are bentonite, barite, barite/hematite blends, and hematite alone. The high specific gravity minerals, barite and hematite, are used to increase drilling fluid density. Bentonite clay is used to increase drilling fluid viscosity and gel strength and to provide a low permeability filter cake. A multimillion dollar investment in a well and the safety of the personnel on the drilling rig can depend on how effectively these mud additives perform with other constituents in the mud. This paper points out effects caused by small amounts of certain carbonate and sulfide mineral impurities in barite or hematite and how polymeric extender additives in bentonites contribute to unpredictable behavior of a mud. Effects like these are the reason oil companies using these materials sometimes set their own quality standards beyond those already specified in APZ Spec. 13A. Also discussed in this paper are the current standardization activities of API Committee 13 on these minerals.

Jan 1, 1988

By A. Sfougaris

A study on fauna distribution and abundance is being conducted in the Giona Mountain, in central Greece, area of bauxite mining. The specific aims of the study are: a) to estimate and map the distribution of mammals, and especially of the Balkan chamois, b) to estimate and map the distribution and abundance of breeding birds, c) to count the bird species using the area during spring and autumn migration and winter, d) to update the list of mammal and bird species of the mountain, with emphasis on rare and endangered ones, according to 79/409, 92/43 EU Directives and other relevant conventions, e) to compare the bauxite mining areas and species distribution and assess the possible overlap and compatibility of mining activities - species conservation, f) to assess the possible habitat loss due to planned mining activities. All estimations of mammal species distribution and abundance are being carried out by fieldwork using spotlight during the night along selected routes. Especially for chamois, line transects and vantage points with the aid of telescopes and binoculars are being used. Birds are being counted with the point count method in randomly selected plots distributed in all available habitat types and altitudes. The species distribution and mining areas will appear on thematic maps with the aid of a geographical information system (GIS). Finally, solutions for environmentally compatible mining activity in the area will be proposed.

Jan 1, 2007

By C. Timothy Shaw, Michael Karmis, Hans de Ruiter

The Society of Mining Professors/Societät der Bergbaukunde was established during a meeting hosted by the Montanuniversität, Leoben, Austria, in 1990. Since then, the Society has primarily functioned as a European entity of senior academics in the mining engineering discipline. The Society is considered the natural successor of the historic Societät der Bergbaukunde, formed in the early 18th century and recognized as the world’s first international scientific society. At the 14th Annual General Meeting of the Society, in Milos, Greece, 2003, a decision was made to examine the role of the Society in global minerals education, to reassess its vision and membership guidelines and to develop the future direction of the organization. A special Planning Subcommittee developed a plan of action to allow the Society to transform and position itself as the premier global voice of the academic minerals disciplines and to lead the effort of restructuring minerals education. The new vision calls for reconstituting the Society as a vibrant global society, representing the majority of minerals academics and making a significant contribution to the future of the minerals disciplines. This paper will present the history, vision, goals and action plans of the Society to help ensure that the necessary scientific, technical, academic and professional skills are available for the sustainable supply of minerals to mankind.

Jan 1, 2005

By Barbara Maren Winkler

For mine production problems in mines with varying qualities, both open pit and underground, the linear programming method (LP) has been used successfully. By this method it is possible to keep the total production blend for each period within a required range of qualities while optimizing objectives like production costs, net return, ore grades, other qualities, or a combination of these. Technical restrictions like constrained capacities can be added to the model. This makes LP a flexible and powerful tool for mine production planning. Practical experiences have shown the major influence fix costs have on the actual economic result of a planning decision. It can be proven that fix costs cannot be included in LP models. We describe a way to address this fix cost problem by using mixed integer linear programming (MILP) as an extension to LP in the optimization of a mine planning problem. This raises the issue of complexity. We discuss the computational complexity of the resulting models and the enhancement of model flexibility for the user of a planning system. We demonstrate the method embedded in a practicable everyday planning system for a complex underground coal mine. By computational examples we show how the method improves the economical results of the planning.

Jan 1, 1996

By Michael E. Kelahan, Charles Y. Guan, Glenn A. Gruber

A comparison of the IMC Anionic Process and the CLDRI Process, based on pilot plant testing of waste pebble by Jacobs Engineering is presented. Estimated costs for constructing and operating a beneficiation plant utilizing dolomite flotation are given. Research to develop practical flotation processes for removing dolomite from low-grade phosphate rock has been a high priority for the Florida Institute of Phosphate Research. The Institute funded the above pilot plant programs in 1998 and 2000. The Florida Phosphate industry currently deals with the increasing dolomite content of ore reserves by practicing selective mining. Heavy media separation plants installed at two mines to remove dolomite from pebble are not being operated. The flotation separation of dolomite from waste pebble requires that the flotation feed be ground. Grinding liberates the mineral species and produces particle sizes small enough to be floated. Only two dolomite flotation processes, the IMC Anionic Process and the CLDRI Process, have been successfully demonstrated on flotation feed that has not been deslimed after grinding. Deslimed flotation feed, relative to undeslimed feed, has improved flotation performance and reduced reagent consumption. However, for the above mention processes, undeslimed ground feed increases the yield of concentrate because the phosphate desliming losses are avoided.

Jan 1, 2002

By R. W. Seedsman

Mandalong Mine was originally planned to operate with panel widths of 250 m and a predicted surface subsidence in excess of 3 m. The consent conditions applied by the NSW government on this mine plan were very tight and, following a change in ownership, were considered by the new operator to present a number of unacceptable business risks An acceptable risk profile for the mine layout restricted surface deformations to less than 500 mm vertical subsidence, less than 7 mm/m tilt, and less than 5 mm/m strain. Empirical subsidence prediction methods indicated that it would be necessary to reduce extraction panel widths of 80 m - an uneconomic option. The application of a number of rock mechanics concepts identified that the local overburden geology could be exploited such that panel widths of up to 175 m could be possible. The 125 m width was selected as a low-risk introduction of this new subsidence prediction method. The extraction of the first 2 longwall panels has demonstrated the validity of the prediction subsidence method and has provided the opportunity to refine the selection of key input parameters. The impact of mining through a zone of thrust faults was successfully predicted. The mine is now planning the introduction of 160 m wide panels, and will review the associated subsidence impacts prior to any further increases in width.

Jan 1, 2006

By V. T. McLemore

Rare earth elements (REE) are becoming more important in our society. REE deposits are found throughout NM. Some REE past production (1950s), as bastnaesite, came from the Gallinas Mountains district, Lincoln County, NM. Several companies and the U.S. Bureau of Mines (USBM) have conducted exploration programs to identify REE potential. Four types of deposits are found in the district: epithermal REE-F veins, Cu-REE-F veins, REE-F breccia pipe and iron skarn deposits; all are associated with Tertiary peraluminous, alkaline to alkalic-calcic volcanic rocks. District zonation is defined by base metals (REE-F-Cu veins) that form center of the district, surrounded by REE-F veins. The magmatic-hydrothermal breccia pipe deposits form a belt partially surrounding the veins. Iron skarns formed at the top and edge of the trachyte intrusion and are likely the earliest stage of mineralization. In 1991-1992, USBM calculated an inferred resource of 0.487 million metric tons with a grade of 2.95% total REE. With the projected increase in demand of REE, areas such as the Gallinas Mountains district in New Mexico are being re-examined for additional REE potential.

Jan 1, 2011

By B. P. Mohanty, D. A. Shores

During the induration of fluxed taconite pellets, alkali salts deposit on the grate support bars, causing severe corrosive degradation of these alloys. To determine the source of these deposits and to understand the mechanism by which the salts are conveyed to the grate bars, a study of the reactions between fluxed pellets and combustion gas was carried out. The study focused on the thermodynamics and kinetics of several processes associated with induration; namely, oxidation of magnetite, calcination of flux, and the formation and gaseous transport of various alkali salt species. Both theoretical and experimental techniques were used. It was concluded that the principal source of alkali salt deposits is alkali chlorides, which are present as contaminants in the flux and/or residue from contaminated washwater. The pathway from pellet to grate bar involves the following steps: evaporation of chloride salts within the pellet; diffusion of salt vapor out of the pellet, aided by the outflow of CO2 from calcination of the flux; convective transport by the combustion gas with concurrent (partial) conversion to alkali sulfates by reaction with residual SOX in the combustion gas; and condensation of salts on the grate bars.

Jan 1, 1998