Search Documents

By Peter C. Lighthal, Harvey N. McLeod, Iain G. Bruce

This paper describes the practical aspects of handling cyanide leach tailings. Alternative systems for cyanide destruction are briefly discussed. The provision of adequate retention time to allow natural degradation of cyanide during summer months is the most economical method of cyanide destruction. Cyanide in ground- water can frequently be both persistent and mobile, so that tailings basins should be designed to limit seepage. Common methods for limiting seepage are presented. Other aspects addressed are water balance, winter operation and abandonment of cyanide tailings systems. A case example of the Cheni Gold Mines Lawyers Creek Project tailings handling system is presented.

Jan 1, 1987

By Carlos E. Avila, Ronald D. Evans

The results of an experimental research program to measure the non- Darcy flow coefficient as a function of temperature and overburden pressure are presented. The experimental values of the non-Darcy flow coefficient were measured over a temperature range of 70-200°F (21°-93"C)and overburden pressures of 1000-4000 psia (68-272 atm). The data obtained confirm that the non-Darcy flow coefficient is a function of rock and fluid properties and is not solely dependent upon the former has been routinely assumed in the literature.

Jan 1, 1986

By David A. Roberts, Edward J. Cording, James W. Mahar, Robert A. Robinson, Noppadol Phienweja, Harvey W. Parker

Horizontal inclinometer and deflectometer casings were used to measure deformations up to 15.2 m (50 ft) ahead of and adjacent to the heading in highly fractured and sheared shales at the Stillwater Tunnel. The measurements were compared with borehole extensometer and tape extensometer deformations to evaluate ground movements in advance of, adjacent to, and behind an advancing tunnel heading. Ground deformations of up to 127 mm (5 in.) occurred during passage of the innovative "walking blade-gripper" TBM. Deformations were compared with curvometer/distometer and vibrating wire strain gage data from steel ribs to assess rock-support interaction.

Jan 1, 1985

By Gao Zhizhong, Zheng Shibo, Gu Zhengxing

Extensive research on the beneficiation of Florida dolomitic phosphate pebble has been carried out by Lianyungang Design and Research Institute of China (CLDRI) in recent years. Test results indicate that the fine-particle flotation process could be used to effectively recover the phosphate values from Florida high-dolomite phosphate resources. With the CLDRI fine-particle flotation technology, a phosphate concentrate with 31% P2O5 and less than 1% MgO could be obtained from a flotation feed containing 25.8% P2O2 and 2.2% MgO at an overall P2O5 recovery of up to 85%.

Jan 1, 1999

By Akira Usui

Ferromanganese crusts on topographic highs in the western Pacific Ocean are believed to be potential resources of cobalt, nickel and platinum. Earlier shipboard geological and geophysical studies by Japanese organizations have focused on mapping of distribution of thickness and metal contents of the deposits when estimating the total reserves. This paper summarizes our attempt to obtain more feasible data of distribution patterns and configuration of the deposits which are important parameters for resource evaluation at some seamounts in the South Pacific Ocean. Morphology of the seamounts and micro-topography of the sea floors are described using shipboard acoustic remote sensing, deep-tow sonar images, and TV/camera. [ ]

Jan 1, 2008

By Chris Mark

In the wake of the Crandall Canyon mine disaster, the U.S. Congress asked the National Institute for Occupational Health and Safety (NIOSH) to study the safety of deep cover pillar recovery operations in the US. The legislation defined ?deep cover? to be greater than 1,500 ft, but NIOSH is also evaluating mines at depths greater than 1,000 ft when multiple seam interactions are encountered. By these definitions, there about 35 active mines that engage in deep cover pillar recovery, in the states of UT, CO, VA, WV, and KY. To date, NIOSH has documented ground conditions and ground control experience at nearly all of them. This paper provides an overview of current deep cover pillar recovery practice. Specific ground control issues that are discussed include: Pillar and barrier pillar design, ? Coal bumps, Thick seam pillar extraction, and ? Multiple seam interactions.? INTRODUCTI

Jan 1, 2009

By S. R. Rao, J. A. Finch, E. El-Ammouri, K. Ngoviky, P. A. Disten

Sludges produced by lime treatment of acid mine drainage (AMD) can contain significant quantities of base metals which represent both a potential hazard and a loss of values. A new technique for metal recovery from sludge is proposed by combining selective acid leaching and adsorption of metal ions by activated silica sol. The process is demonstrated on two AMD sludges, one containing primarily nickel and the second zinc. They were first treated with sulphuric acid (pH 3.5) to selectively leach the target metals and then activated silica sol was added to the leach solution to adsorb the nickel and zinc. Thickening and centrifuging gave about 90 percent rejection of the input volume to effluent. The adsorbed metals were redissolved by strong acid into a concentrated solution relative to the feed and the silica sol was recycled.

Jan 1, 2000

By P. C. Rath, K. Srinivasa Rao, T. Subbaiah

A process for the recovery of nickel from ammoniacal leach liquor through an integrated solvent extraction-electrowinning (SX-EW) flowsheet was tested on a pilot-plant scale. The objectives of the test run were to assess the reproducibility of laboratory-scale data in a large-scale continuous operation and to study the build up of impurities in the system. The pilot-plant test was conducted under operating conditions that were established from the laboratory-scale experiments. Efficiencies of nickel extraction, nickel stripping and ammonia scrubbing were comparable to the laboratory-scale values, whereas the current efficiency during nickel electrolysis was observed to be less than the laboratory-scale values. The electrodeposited nickel contained some cobalt and iron impurities.

Jan 1, 1998

By C. DeRossett, K. F. Unrug

Sedimentary rock fractures commonly occur in the vicinity of outcrops. Mine highwalls and highway cuts provide excellent views of these near-surface joint systems. This paper explains the origin, characterization, distribution and extent of the these joint systems with reference to the lithologic composition of the rocks. The practical implications of these joint systems on the operation of a mine are described. Included are discussions of the discontinuous deformation that results from surface subsidence, the stability of mine portals and near-outcrop underground operations, and the stability of highwalls when using highwall miners and strip operations. Some design procedures are recommended to minimize the problems encountered within mining areas having intense joint systems.

Jan 1, 1996

By Merwin Bernstein

Peru has been an important source of metals since Aug. 29, 1533. On that day Francisco Pizarro took charge of the 24 t (772,000 oz) of gold and silver that constituted Atahualpa’s ransom. At today’s prices, the value of that booty ranges between $100 and $150 million, depending on the proportion of gold to silver. Since then, Peru’s silver and gold production has been legendary. Current mine production Most of Peru’s metals are mined from the Andes Mountains and its foot-hills. The Andes run the length of the country parallel to the Pacific coastline from Ecuador to Chile, a distance of nearly 3000 km (I 875 miles). They are about 300 km (187 miles) wide and much of the range is more than 3000 m (9900 ft) in elevation. High plateaus (altiplanos) occupy a large part of the range. Both flanks are rutted by large valleys and canyons. Many of these peaks are prodigious. which make road building expensive and adds to the cost of mining.

Jan 1, 1993

By H. Y. Sohn, H. K. Lin

The leaching of primary porphyry chalcopyrite ore under simulated solution-mining conditions was studied using a packed-bed reactor. A mathematical model incorporating the intrinsic leaching kinetics of chalcopyrite and pyrite grains, the pore diffusion of dissolved oxygen within the ore fragments, liquid-solid mass transfer, and the effect of fluid flow and axial dispersion was formulated and tested for the overall leaching process. The dependence of oxygen solubility on ionic strength of the solution was also incorporated into the model. Satisfactory agreement between model pre- dictions and experimental data was obtained. The model can also predict the rate of the leaching process under different temperatures, oxygen pressures, solution flow rates, and different size distributions of ores.

Jan 1, 1991

By F. Seymour

A modified three-dimensional Lerches-Grossmann (LG) graph tree algorithm that generates the complete set of nested maximum valued pits in a single run is presented. This modified LG algorithm looks at the relative strength (average value) of the branches (groups of blocks). Pointers are allocated and pruned until there are no members of weaker (lower average value) branches overlying members of stronger (higher average value) branches. The final set of strong branches arc listed in order of decreasing strength. The pits they represent form the maximum valued convex hull for a single-variable pit-limit parameterization. A description of the algorithm is given along with examples of lion it has been applied at Newmont.

Jan 1, 1996

By S. P. Lucido, I. Iwasaki

The potential of controlling heavy metal ions in effluents from discontinued mining operations and waste rock piles has been investigated. A fresh water green alga, Cyanidium caldarium, was found to have the potential to remove Cut' from solutions while exhibiting high tolerance to acid conditions which are commonly encountered in copper-nickel mine drainage. The process has the potential for application as a low maintenance metal decontamination system. The growth requirements and copper removal characteristics of this microorganism are described.

Jan 1, 1991

By Bradford F. Townsend, Gary Peach, Roger Rothenburger

From the experience of the authors on recent large infrastructure Design-Build projects this paper reviews major lessons for Contractors and Owners in the delivery of large Design-Build infrastructure projects and some major pitfalls and warnings to both Owners and Contractors. The paper is written from both the Design and Construction perspective. A case history is presented that details the approach employed to ensure a quality project consistent from the initial design phase through construction and outlines the strategy used to guide the Design-Build process to an acceptable completion. Suggestions are made for Contractors and Owners for handling the Design and the Construction elements of Design-Build contracts.

Jan 1, 2003

By Slobodan Vujic, Goran Cirovic, Dragan Radojevic

Mine production systems (MPS) are characterized, more or less, by the following properties: uncertainty, subjectivity, impreciseness, polysemy, instability, indefiniteness and lack of data. From modern study aspect these MPS mathematically belong to the class of fuzzy systems. With this in mind, the usage of fuzzy sets is recommended as a methodology that treats impreciseness, indefiniteness and complexity of mine production systems in a satisfactory manner. Fuzzy modelling, discussed in this pa- per, is applied as a mathematical implement. The objective of the paper was to show production optimization in practice on the ex- ample of bauxite open pits where fuzzy linear programming (FLP) was used following the criterion per income. The variables in criterion function are linguistic variables while both variables and variable restrictions are presented by triangular fuzzy numbers (TFN). The term "satisfactory income" presented through triangle fuzzy numbers was introduced instead of "maximizing the income". sensitivity of the obtained solutions has been analysed

Jan 1, 1996

By Frederick W. DeVries, J. Brent Hiskey

Cyanide has been recognized for about a century as the most effective reagent for processing gold ores. Cyanide leaching has been adapted to various metallurgical settings and continues to be improved. However, in recent years attention has been directed to alternative lixiviants for treating refractory ores and concentrates, and to the development of less environmentally controversial substitutes for cyanide. This paper reviews some of the reagents considered as alternatives to cyanide and focuses on environmental implications for using these newer reagents.

Jan 1, 1992

By Hugh W. Rimmer

The design of comminution circuits and the evaluation of alternatives should be based on state-of-the-art equipment and appropriate design criteria - considerations that are often neglected by today's designers. This paper critically reviews common circuit designs, evaluates various alternatives for difficult-to-treat ores, and discusses the factors that should be considered when developing new plant designs or auditing existing plant performance. Data obtained from laboratory, pilot and plant-scale test work on a wide range of ores and circuits are used to justify the author's conclusions.

Jan 1, 1995

By Thomas P. Kwiatkowski, John S. Anderson

The Massachusetts Bay Transportation Authority (MBTA) has undertaken an under-ground transit project to extend public transportation service from downtown Boston to the South Boston Piers area. This new system, known as the Transit way, will connect existing subway lines to this area which is comprised of approximately 300 acres, in light of the potential for 21 million square feet of development by 2010. This system includes construction of a concrete immersed tube tunnel crossing of Fort Point Channel. The crossing will be accomplished in the highly congested setting of down-town Boston and will be located just to the north of the famous Boston Tea Party ship exhibit and amid major Central Artery Construction activity. The most recent concrete tube constructed in the United States was in 1962. The Fort Point Channel Crossing will employ current design and construction methods commonly utilized in the Netherlands, Australia, Hong Kong and elsewhere. This paper will present the design philosophy, planning, and evaluation of alternative crossing methods which led to the selection of the concrete immersed tube tunnel and construction techniques envisioned for this particular application.

Jan 1, 1997

By L. Korkiala-Tanttu, M. Rinne, Z. Song

Disposal of mine tailings has been recognized as an unavoidable burden of mining companies and local authorities. Conventional methods dispose mine tailings in a passive manner which hardly generates any value from them. On the other hand, growing local communities close to mines need more infrastructures which require great amounts of raw materials. In view of the above mentioned situation, a novel utilization of mine tailings is explored as alternative material for asphalt pavement, in order to extract more value from mine tailings and solve the high cost of pavement material. Inherent physical properties of the mine tailings were first investigated to find out their availability as pavement material. Then test specimens were made as mixture of the mine tailings and other pavement material to be tested in laboratory. The mine tailing materials presented a considerable potential as asphalt filler for low-volume roads. Furthermore, the limitat

Jan 1, 2011

By K. A. Grace, D. E. Ranta

The application of geology does not cease with the discovery and delineation of a mineral resource, but continues in the calculation of the economic parameters that determine reserves. Reserve determination, reduced to essentials, is the determination of the cost of production of a mineral commodity from a resource. This cost comprises mining, processing, waste disposal, reclamation and marketing costs. Geological input is vital in the calculation of the individual cost parameters from mining to reclamation, and even has same impact on marketing. Geology thus has a critical role in the determination of reserves.

Jan 1, 1992