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By W. M. Lewis

Product losses to tailings ponds have long been a source of frustration for the mining and utilities industries. The utilization -of the Lewis Econosizer to recover lost products has proven to be very cost effective through reduced acreage requirements, cleaning costs and increased production. The unit is successfully operating in coal, aggregates, industrial minerals, clay, fly ash, heavy minerals and many other ores. Utilizing an upward flow of slurry in a free settling environment, particles stratify within the unit according to settling velocities and are removed as sized products. Ultra fines or clarified water is removed off the top of the unit. The Econosizer requires no power and only minimal maintenance.

Jan 1, 1998

By Antonio Dominguez-Perez, Annette Dickmann, Roy Norcross, Andreas Rubo, Stephen Gos

With increasing cost pressure in the production costs of gold, there have been great efforts made to reduce the gold production costs as much as possible and a great deal of effort and lateral thinking is required to maintain a cost effective gold production facility. In a difficult economic environment, there is always the danger of saving in the wrong place. Just like it can be fatal to cut down on innovative research and development for long-term existence and sustainability in most industries, savings in safety and visionary planning of regulations expected in the future can become very costly on the long run, if preventative measures are not taken, observed or ignored. This paper deals with some current topics pertinent to the gold mining industry with regard to the interaction between potential risks, regulations and the costs that arise and can be saved in relation to these. Only an optimal combination of cost effective, safe and technically feasible regulations enable an operation to work economically.

Jan 1, 1999

By Sukumar Bandopadhyay

In recent years planning of surface mines in general and reclamation and post-mining land uses in particular have become very complex. Due to the lack of suitable techniques, land use plans are rarely based upon structured decisions. Data collection may be conducted in a rigorous manner and certain analyses may be performed on the data; the decision to put the land to a specific use, however, is finally based upon the intuitive judgment of one or several individuals. This paper demonstrates how techniques from fuzzy set theory can be used in order to select an optimum post-mining land use plan. The various land use planning alternatives have been characterized according to both qualitative information and quantitative factors and the "fuzzy" aspects of the collected information are incorporated into the analyses. In a practical application, the methodology is used to obtain the most reasonable solution to a post-mining land use planning problem in Interior Alaska.

Jan 1, 1986

By G. Pierson

Explanations for commodity price levels (or movements) commonly focus on the fundamentals of supply and demand otherwise they are simply assigned to speculative activity. Comparisons of metal-price histories to monetary and other economic data support the argument that the supply of and demand for money are no less important in the determination of price than are the supply and demand of the commodity itself. That these relationships should exist is evident in the price identity and they are consistent with monetary theory. The patterns developed have limited usefulness as predictors, but their recognition is essential for the construction of price scenarios for planning purposes.

Jan 1, 1998

By Ian Sheppard, John J. Chen

This paper describes the development of the underground mining methods employed for narrow silver-lead-zinc orebodies at the Isa Lead Mine. Cut-and-fill methods were the chief underground mining methods for the narrow orebodies at the mine over 35 years ago. Benching methods were introduced approximately two decades later, and quickly replacing the cut-and-fill methods. The cut-and-fill methods and the benching methods are briefly reviewed in the paper. The benching methods and technologies have been continually evolving and one of the recent achievements is a multi-lift benching method. The multi-lift benching method is described in detail.

Jan 1, 2001

By R. Mensah-Biney, M. T. Hepworth, K. J. Reid

The kinetics of gold-bromide loading onto activated carbon was investigated in a batch stirred reactor. Based on a second-order equation, the amount of gold adsorbed by the carbon was correlated with time. From a 30ºC solution containing 25 ppm Au and 0.8 g/L carbon, the rate constant for gold-bromide species onto activated carbon ranged from 0.27 x 10-3 to 1.2 x 10-3 (kg/t)-1 min-1. The equilibrium saturation capacity (Qe) was 36 ±3.0 kg/t from the same system. The rate of loading increased with increasing temperature and decreasing particle size, pH and solution gold concentration. The calculated activation energy (Ea) was 8.8 kcal/mole, significantly higher than those reported for physical adsorption. The equilibrium saturation capacity (Qe) increased with increasing concentration of gold in solution but was independent of other variables such as temperature, agitation speed, particle size and pH. These rate constants and equilibrium saturation capacity for the gold-bromide species are higher than those reported for the gold-cyanide systems.

Jan 1, 1998

By M. Karmis

According to international projections and future energy scenarios, coal will continue to be a prominent fuel for the next 25 years. In fact, in many regions around the world, coal is expected to dominate the electricity sector until the year 2030. At the same time, with instability and volatility of oil prices, coal is also positioned as an alternative feed stock for conversion into liquid fuels. Energy economists maintain that coal liquefaction is viable at crude oil prices of $35 or more per barrel. Depending on technology and coal composition, 1 ton of coal can produce 1 to 4 barrels of oil. Increased coal production and the expanded utilization of coal also raise environmental concerns regarding greenhouse gases and the problem of handling CO2. Carbon sequestration research, currently conducted in many parts of the world, has demonstrated considerable potential for C-storage in unminable coal seams. Such geologic storage, when possible, can also be integrated into an enhanced coal bed methane recovery process Can coal fuel power plants and industrial facilities, provide diesel and other liquids and, at the same, also be used as a medium for permanently storing CO2? This presentation will provide a global perspective on these questions and stress on the need to reconsider, or even redefine, coal as the fuel for the future.

Jan 1, 2006

By Martin L. Smith

Sampling and subsequent geostatistical structural analysis is being carried out on the Bunker Hill Superfund site in northern Idaho's Silver Valley. This paper reports on the findings and methodology used in the initial sampling campaign which had the goal of determining an appropriate sampling grid design, spacing and protocol. Emphasis is placed on those characteristics, of mine wastes which are unique and require special consideration when applying geostatistical analysis. This study represents one of the first applications of geostatistical techniques to the problem of hazardous mining waste site characterization. Remediation of Superfund projects similar to the one described herein represents opportunity as well as liability for the mining industry.

Jan 1, 1992

By Rex C. Bryan

An accurate and dependable ore reserve estimate is important to any mining company. It is also essential for development drilling and production planning to know about the distribution of the ore within the area to be mined. This paper will show that in the case of more variable deposits such as uranium, the use of geostatistics is superior to conventional techniques. Unlike conventional methods, geostatistics includes the importance of spatial orientation of measured variables. With the use of variograms in conjunction with kriging, a point or a block may be estimated along with its error of estimation. The existence of disequilibrium can create a severe problem in uranium 'ore reserve estimation, and mine and production planning. Disequilibrium can be simply defined as the ratio of chemical or assay values to gamma equivalent values calculated from the downhole geophysical gamma-ray logs. Various methods for adjusting for disequilibrium have been proposed. Most, however, have side stepped the consideration of disequilibrium itself being a regionalized phenomena; or its, relation to surrounding geology. This paper presents methods of incorporating both aspects. The East Dilts Pit at the Bear Creek Uranium Mine in Wyoming, has been used as a case study. Polygonal, triangular, and lognormal kriging and various disequilibrium adjusted methods, including multi-factor cokriging have been com- pared with the mining experience.

Jan 1, 1982

By Brij M. Moudgil, Ivan U. Vakarelski, Yakov I. Rabinovich

Polymer and surfactant dispersant are widely used to disperse filler particles within a medium. Sur- faces active dispersants form self-assemble structures at the solid-liquid interface. The mechanical properties of the surfactant structures have been determined to strongly influence the dispersion behavior. In this study the atomic force microscope (AFM) is used to determine the elastic modulus and yield strength of a steric dispersant layer adsorbed to a rigid non-deformable surface. To interpret these values a model for elastic body contact based on a modified Hertz theory is applied. The results from this method may aid in the design of application-based dispersant systems.

Jan 1, 2003

By G. Pierson

Explanations for commodity price levels (or movements) commonly focus on the fundamentals of supply and demand, otherwise they are simply assigned to speculative activity. Comparisons of metal-price histories to monetary and other economic data support the argument that the supply of and demand for money are no less important in the determination of price than are the supply and demand of the commodity itself. That these relationships should exist is evident in the price identity and they are consistent with monetary theory. The patterns developed have limited usefulness as predictors, but their recognition is essential for the construction of price scenarios for planning purposes.

Jan 1, 1997

By J. M. Mutmansky, A. Wang

This paper defines the elements of a basic economic model for decision making when considering a methane drainage system for an underground coal mine. A drainage system entails significant capital and operating expense; hence the decision to utilize drainage must be made carefully. The model outlines the basic structure of decision making and considers the costs and benefits when the methane is marketed and when the methane is vented to the atmosphere. The effects on mine safety and the dust levels in the mine are also considered, both in a general format and as economic variables. Sources of information for executing this decision making are provided for an actual mine decision.

Jan 1, 1999

By K. M. Belingheri, M. E. Smith

Pinson Mining Co. operates a conventional mill and two heap leach operations in north-central Nevada. The latest of these heap leach operations, the Preble project, is a low-grade, low-tonnage property made profitable through several innovative capital reduction techniques. Rapid return on investment was a prime factor in design. To facilitate this, fast-track design and construction techniques were employed. The project is a seasonal 1.5 kt/d (1 700 stpd) crush/agglomerate heap leach plant using both clay and plastic leach pads. Construction and startup were achieved through cooperative arrangements between local contractors and in-house construction personnel, with few items put out to bid. An interactive approach to design minimized lost time and construction costs.

Jan 1, 1987

By J. Girard-Dwyer, J. Johnson, J. Whyatt

The choice of fragmentation method is one of the most fundamental aspects of mine design, and often has a major impact on the safety and economic viability of an operation. Almost exclusively, underground mining operations rely on either mechanical excavation or drill and blast techniques to extract rock. Each of these fragmentation methods has distinct advantages and disadvantages, and each is appropriate, and economic, for different mining conditions. However, the choice of fragmentation method can have a pronounced effect on the amount of damage created in the rock mass surrounding the opening. This paper reviews a number of case studies where both mechanical excavation and traditional drill and blast were used in underground mines. Ground support requirements in the mechanically excavated areas are compared to the support requirements in the blasted sections in order to demonstrate the potential safety and cost benefits of the various fragmentation methods.

Jan 1, 2003

By Ben L. Seegmiller

The basic compression-yield concept of roof support for mine roadways requires that the mine roof be placed in a state of compressive stress. The compressive stress may be achieved using a support system such as an entry truss or other specialty truss device. Furthermore, the roof must be allowed to yield, but with great resistance when abutment loads are placed on the roadway. The resisted yielding may be provided using a new yieldable steel prop, known by the trade name, YIPP~. The yieldable steel prop can allow as much as 1.5 m[5 ft] of yield, or up to approximately 40% of the opening height, while providing a resistance in excess of 60 mt[66st]. More than fifteen mining operations including coal, trona and hard rock mines have field tested the YIPPI . Present results indicate that the yieldable prop provides a cost-effective alternative to wood cribs, concrete cribs, hydraulic props and other steel prop supports. The paper describes the YIPPI including its unique principle of operation, its applications and actual field performance.

Jan 1, 1992

By David Sainsbury, Bevan Thompson, Yuejun Cai

The practice of placing loose rockfill as passive support in open stoping voids, of narrow vein mineral deposits, lends itself to the sterilisation of substantial mining reserves in the requirement for regional crown/sill pillars. Significant benefits are to be gained by the Australian mining industry via the development of improved guidelines for the extraction of such sterilised mine pillars. The application of selectively injecting specifically developed ettringite (calcium sulphoaluminate hydrate) type cement grout into loose rockfill, enables an artificial pillar to stabilise the surrounding rockmass and prevent the caving of loose rockfill from the previously backfilled void during extraction of remnant crowdsill pillars. This paper presents the results of laboratory testing used to reduce the technical risks associated with the design of cemented rockfill pillars. A laboratory testing program was devised to investigate the critical parameters influencing the performance of a stabilised rockfill matrix, along with the critical parameters influencing the interpretation of laboratory test samples. The factors investigated include; sample size and shape, particle size distribution, curing time, water quality, cement : water ratio and the confinement effect.

Jan 1, 2001

By J. P. Stone

The Mining Regulatory Affairs review arrived in time for the May issue. The Managing Editor inadvertently buried it in one of his paper piles. Regulatory developments at the federal level involving the minerals industry solid waste disposal under the Resources Conservation and Recovery Act (RCRA) remained at the forefront of concern. The Environmental Protection Agency (EPA) received public comments on two major documents. One was a strawman draft rule covering wastes from mining and beneficiation. The other was a report to congress covering selected mineral processing wastes. The regulation of minerals industry waste management is moving forward on parallel paths. Mining and beneficiation waste is somewhat further advanced.

Jan 1, 1991

By D. W. Fuerstenau, P. C. Kapur

A model equation is presented for breakage of single particles as a function of the impact energy. The model takes explicit cognizance of the distribution of feed particles in their resistance to breakage as well as of the weakening of particles under repeated impacts. With the proposed formulation, it is possible to simulate the size spectra of progeny particles, interrelate quantitatively the so-called ‘t’ family of curves, derive an energy-size reduction relationship, compute the primary, energy-free breakage distribution function, and predict the optimum level of impact energy for a given size reduction task. Published data on single-particle impact grinding are in agreement with the model.

Jan 1, 1995

By Richard H. De Voto

The Pb-Zn-Ag deposits within the Lower and Middle Paleozoic strata of central Colorado (Leadville, Gilman, Aspen, and others) occur principally in Late Mississippian karst-solution features within dolomites and, to a lesser extent, limestones. Several un- conformities within the Devonian and Mississippian carbonate rocks and the subregional dolomitization of the Leadville (Mississippian) Formation that occurred during the Late Mississippian resulted from recurrent uplift of elements of the Ancestral Sawatch, Gore, and Front Range areas within central Colorado. Uplift of these areas also strongly influenced the details of the extensive karst topography that developed during the Late Mississippian. In particular, uplift of the Sawatch Range area caused paleovalleys from 300-600 ft deep to form on the karst landscape. The pattern of karst-solution caverns, sinkholes, cutters, channelways, and breccia-rubble zones was strongly controlled by incision of surface drainages and the strong northeast-trending Mississippian joint system. These subterranean karst-solution features and breccia-rubble soil [ ] zones are the primary controls of the location of the Pb-Zn-Ag ore deposits in these rocks. In the Leadville and Aspen districts, the deeply incised paleovalleys occur immediately adjacent to the principal areas of mineralization. Pennsylvanian deposition of a thick terrigenous and evaporite sequence occurred within central Colorado in response to actively subsiding extensional basins and adjacent high-relief uplift areas. Hot brines developed within the Pennsylvanian strata, migrated laterally to, and moved upward vertically along, basin- margin faults during continued Pennsylvanian subsidence and deposition. These metal-rich brines migrated into karst-solution features within the Lower and Middle Paleozoic dolomites and limestones, principally within the Leadville Formation, in basin- edge uplifted locales where the Pb-Zn-Ag minerals were precipitated. Field relationships, mineral assemblages and paragenesis, fluid-inclusion data, and isotope studies suggest that the metals and brines were derived within the Pennsylvanian sedimentary sequence and that the ore minerals were deposited under different temperatures and at different depths from deposit to deposit. Chemical reaction with the carbonate cave sediment and wallrock, cooling of fluid temperatures, and mixing with meteoric ground waters were the probable combined causes of mineral deposition in the karst-solution features. Late Cretaceous-Tertiary intrusive activity has subsequently modified some of the primary Pb-Zn-Ag deposits in local areas.

Jan 1, 2013

By Scott G. Britton

The first section of this text delves into construction engineering techniques for successfully completing necessary underground production support projects. I will discuss alternative design concepts, installation practices, materials and material costs, completion time, and necessary labor for individual projects. The emphasis of this section is on describing each project thoroughly and providing a practical guide for the supervisor or engineer. There are four main construction categories for typical underground mining projects. These are: 1) Transportation of men and supply materials. This refers to track and wire installation and roadbed grading and ballasting. 2) Ventilation, composed of overcasts, man doors, regulators, and stoppings. 3) Drainage, including sumps, pumping stations, drainage networks, pumps, and face drainage. 4) Haulage of coal and rock from the face to the outside. The focus here is in the installation of belt lines, belt drives, transfer points, and vibrating bins/feeders. The first section shall fully discuss these four categories in regard to the construction engineer or supervisor designing, building, or improving a system. In addition, special projects such as surge bins, rotary dumps, and underground offices not classified under these categories will be discussed. For manageable purposes, I have limited the installation discussions to one or two approaches I feel have merit. The variation of installations in coal mining is endless, each with its own advantages and disadvantages. Therefore, the reader should not dismiss or restrict his thinking to only the approaches in the text. It serves as a guide only.

Jan 1, 1983