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By James A. Decker

Hanna has developed three production planning systems to help the mine engineers determine the sequence of mining from available ore supples. The Production Scheduling System was developed to give the staff a tool for long range planning by sequencing the removal of blocks from an open pit property. It was needed to determine the year of removal for each block so that the optimum present-valued pit limits could be established by our pit design program. Since in this type of planning short term grade control is less of a factor than it is in daily or monthly planning, the system gives the program greater control and more latitude in block selection. It permits only full blocks to be taken.

Jan 1, 1984

By W. M. Schafer

The risk that water quality will be degraded by mining activity can be evaluated using risk analysis techniques. Water quality impacts can occur where water-rock interactions with tailings, waste rock, or leached ore lead to increased loading of constituents into surface or groundwater. Constituent loads contributed by mining facilities are determined by the migration route and chemical evolution of mine water. Mass load contributions from mines can be determined by estimating the prototype pore water in contact with mining waste, predicting the rate and timing of flow, assessing the degree of geochemical attenuation, and modeling chemical mixing with natural surface or groundwater. Mining facility siting and design measures can alter the chemical evolution of mine water by varying the quantity or quality of flow. Stochastic risk management techniques provide a powerful tool for quantitatively identifying the environmental consequences of various siting and design alternatives.

Jan 1, 1998

By R. L. Merrifield

Cominco Snip is a 60: 40 joint venture of Cominco Ltd. and Prime Resources Group Inc. Cominco manages the operation. The mine site is located in a narrow mountain valley where Bronson Creek enters the Iskut River in Northwestern British Columbia. Access is by air only to the company's 1,500 meter airstrip. Milling at a designed feed rate of 300 tpd began on schedule in January 1991. Tonnage and gold production in the form of bullion bars from the gravity circuit and gold bearing float concentrate have exceeded design forecast. This presentation will examine many of the factors that influenced the final plant design inclusive of exploration findings, bench scale and pilot plant test results, environmental and social considerations, capital and projected operating costs and product transportation alternatives such as the operation's Hovercraft.

Jan 1, 1993

By P. Michael

Proponents of geomorphic mine land reclamation have criticized current reclamation practices in the coal fields of steep-sloped Central Appalachia as too narrowly focused on civil engineering principles and neglectful of the functional and aesthetic benefits of reclaiming mine sites in ways that mimic natural landforms and drainage patterns. They observe that current mining and reclamation practices are radically transforming the mountain-and-valley terrain into gigantic flat plateaus and, in doing so, disrupting the beauty and ecology of the natural landscape. Instead of designing and constructing linear or planar surfaces and unvarying slope gradients during the reclamation process, they recommend ?landforming,? i.e. the adoption of curvilinear, compound slope forms that blend well with the surrounding physiography and represent the result of naturally stabilizing geomomorphic processes. The authors feel that the concept of geomorphic mine land reclamation is sound, however, its application to the Central Appalachian coal fields faces significant--albeit not insurmountable--challenges. They include: (1) existing reclamation enforcement regulations that are focused on civil engineering principles and not explicitly supportive of geomorphic methodologies; (2) regulatory agencies? current intent to limit the down-gradient reach of excess spoil fills in order to allay disruption or burial of natural streams; (3) actual or perceived increases in reclamation costs; and (4) the challenge of designing and constructing ?natural? landforms that are mature and stable in an otherwise youthful, erosional landscape.

Jan 1, 2010

By Harry Verakis

Electronic detonator systems are an advance in technology beyond conventional electric detonators for initiating explosives and blasting agents. Their use is widening into the mining operations of the U.S.A. Each electronic detonator system differs in design, construction, operation, and testing features and each system is different than “conventional” electric detonators. There are benefits of electronic detonator systems which serve to improve blasting safety. With the introduction of electronic detonator systems for mine blasting, issues were raised about the application of MSHA regulations for shunting and circuit testing. The MSHA regulations for surface and underground mine blasting operations address the use of “electric” detonators. Although electronic detonators are initiated by an electric pulse or current, their design is unlike “electric” detonators. To resolve the issues of shunting and circuit testing with respect to MSHA regulations, a technical and field evaluation of electronic detonators was made and the results are presented.

Jan 1, 2005

By J. Kang

Supercritical fluid extraction (SFE) has became an attractive alternative technology to be a new process to recover metal, of which can be substitute the existing Leaching/Solvent extraction processes. Solvent extraction of metallic ions is a technically important and also well-established process that is used in the chemical and hydrometallurgical industries.1 Solvent extraction techniques use the chelation of metallic ions dissolved in liquid solution with organic ligands. Conventional solvent-extraction technique needs large amount of organic solvents and often creates environmental problems.2 More environment-friendly technology is needed nowadays, and there have been increasing attentions to extract metal ions by SFE. CO2 becomes one of the most notable alternative organic solvents due to its nonflammable, nontoxic, nonpolluting, and relatively inexpensive properties with its moderate critical point (73.8 bar, 31.06 °C). Many works have been reported in metal extraction under the supercritical CO2 (scCO2) solvent.3-5 In this study, to recover cobalt from wastes especially from spent lithium ion battery scrap, we selected two ligands ? Cyanex 272 and DEA (diethylamine) for the metal extraction in scCO2. Cyanex 272 is a commercially available extractant along with its series, Cyanex 301 and Cyanex 302. Smart and coauthors measured the metal extracting abilities of these three extractants, and found that Cyanex 301 and Cyanex 302 extracted metal ions much better than Cyanex 272 in the scCO2 solvent.10 The pH of water contacted with high pressure CO2 (70-200 bar, 25-70 oC) is about 2.8-2.95 based on the calculation and the measurement.6-7 Cyanex 272 is known to be less effective as a metal extractant in this low pH environment compared with other Cyanex series. However, when DEA is added to metal extraction reaction with Cyanex-272, DEA works as a strong base to Cyanex 272 converting Cyanex 272 to a deprotonated form (Figure 1), which results in an easy formation of metal complex and the enhanced extraction rate of metal ion.8 Therefore, the purpose of this paper is the metal extraction from spent lithium ion battery waste using scCO2 with Cyanex 272 and DEA.

Jan 1, 2010

By H. A. Oliveira, A. Azevedo

Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1 ) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.

By S. K. Singh

"Feather edging"-a major source of injury and fatal accidents in Australia, South Africa and USA, refers to a phenomenon where the roof, at the goaf edge, falls as a thin wafer of rock often suddenly, over-riding conventional timber breakerlines. It may run down and affect adversely a working bord at distances of 15 metres or more from the goaf edge. Feather edging typically occurs in relatively massive, strong roof strata such as sandstone or conglomerate. This paper presents the results of a mine trial where a concentrated row of fully grouted bolts were able to resist the feather edging in the first comprehensive, monitored trial in an Australian pillar (&apos;total&apos;) extraction coal mine.

Jan 1, 1999

By J. R. Carr

A crucial concern when implementing computer algorithms for geostatistical analyses on microcomputers is speed of execution. Kriging, in particular, typically relies on a Gauss elimination algorithm to solve for weights. Because such an algorithm is required for each estimate, the solution for weights can result in very slow program execution speed on a microcomputer. One approach to enhancing the efficiency of Gauss elimination is demonstrated herein. The upper triangle plus diagonal of the intersample covariance matrix is used in a modified banded Gauss elimination algorithm. Results show that such an algorithm yields approximately a two-fold reduction in execution time for kriging when the number of nearest neighbors used for estimation is large.

Jan 1, 1990

"The paper treats the spatial aspect of mine sequence optimization. This aspect is revealed in the context of determination of the optimum number of cutbacks of an open pit mine. Cutback mining is a dominating method currently in base\precious metal mining and it is based on a pseudo-economic discretization of the pit space by using advanced pit design algorithms. The result of the implementation of such approach of pit design is the generation of pit shells, which need to be grouped into an optimum number of cutbacks for maximization of the project value. A mathematical solution of this problem is developed with the utilization of a combinatorial analysis. The solution provides a multi-variant investigation of the optimum mine sequence with the implementation of an author’s method for production scheduling optimization, which uses the Net Present Value as a criterion for assessing the economic efficiency of mine sequencing. A case study is provided for the conditions of a hypothetical open pit gold mine to illustrate the applicability of the approach. The results obtained reveal the complex nature of the variation of the Net Present Value as a function of the cutback geometry. INTRODUCTION The mine sequence optimization in open pit mining is a procedure that predetermines the efficiency of the production scheduling optimization. From a technological standpoint, the mine sequence optimization deals with two aspects – spatial and time. Each of them plays a tremendously important role in searching for the optimum solution of the open pit design problem. Original results on the time aspect of mine sequence optimization are published by Halatchev [2002]. They reveal a wide range of the Net Present Value (NPV) variation for a multi-variant arrangement of mine sequence over time and using a fixed geometry of the cutbacks, which determines the economic potential of a single open pit mine from a deterministic standpoint. The results show a range of NPV variation up to 30% depending on the stripping ratio of the mine. The effect of this variation is mainly due to the implementation of the mine planning principle of waste deferment in the scheduling optimization and using all theoretically possible variants of mine sequence arrangement by the inclusion of the bench sequences over the Life-Of-Mine (LOM) in the production process."

Jan 1, 2015

By M. Misra

A sample of thorium-contaminated soil from Kirtland Air Force Base (AFB) was subjected to froth flotation for removing thorium contaminants. A series of flotation tests were conducted to screen and evaluate the reagents. Among the collectors used, sodium oleate exhibited to show the promising results. Preliminary tests showed that a concentrate having activity as high as 5300 pCi/g can be obtained from the contaminated feed soil having activity 800 pCi/g. The volume reduction obtained was 89% and the activity recovery in the concentrate was 68%. The paper discusses the physico-chemical characterization data and the potential physical separation decontamination schemes for the thorium contaminated soils.

Jan 1, 1996

Room-and-pillar mining at White Pine started in 1953 from a sub-outcropping orebody that gently dips to 1000 m depths in a distance of about 6 km. High horizontal stresses were recognized in the mid-1960s which had obvious stability impacts when viewed in combination with the increased overburden stresses. Modifications in conventional room-and-pillar design were introduced through the years on a trial-and-error basis to help overcome stability and resource recovery problems. These modifications were based on pressure arch concepts using pillar yielding and/or pillar recovery, and on mine layout orientation to minimize stress impacts. While some of these modifications were successfully applied in some areas, they failed in others. Through the years, visual observations played a major role in panel design with contributions from stress measurements and analyses. However, the down slide in the copper economy during the 1970s and early 1980s resulted in a loss of interest in the application of these concepts. This paper reviews ground control problems and presents the results of recent stress measurements and computer analyses. They shed light on the importance of using yield pillars and mine layout orientation to control stresses at depth.

Jan 1, 1993

By K. T. Valsaraj

The separation process called solvent sublation for the removal of two hydrophobic compounds (penta-and tri-chlorophenols) from the aqueous phase is discussed. A steady state mathematical model for the process is discussed. The process was conducted in a continuous countercurrent mode. The underlying mechanisms, theory and experimental details on the effects of process variables on removal efficiency are reported.

Jan 1, 1992

By Donald E. Zipperian

It has been recognized that froth flotation of mineral particles utilizing rising flow of micro size air bubbles, counter-current to quiescent falling flow of particles in a column type cell, provides a unique mechanical atmosphere conducive to extension of froth flotation process to much coarser and finer particles sizes than possible with mechanically agitated and aerated cells. 1,2,3,4. This paper describes metallurgical results obtained at several plant installations of large capacity commercial size Deister FLOTAIRE® Column Flotation Cells. These cells utilize air aspiration into surface tension lowered water to generate micro size bubbles. Operating costs, power, wear, and scaling characteristics of rougher, cleaner, and scavenger units are compared with mechanical units. Problems encountered and scale up criteria developed when increasing from 0.20m(8inch) diameter pilot cells to 2.42m(96inch) commercial cells are discussed.

Jan 1, 1985

By Z. Yunquan

The flocculation and dispersion behaviors of microsize wolframite and quartz are systematically studied in this paper. For synthetic mixtures, the floc separatory method on gravity units--electromagnetic vibration table (EVT) and lifting column (LC), have been approached. Satisfactory results can be obtained with a weak shearing. A better metallurgical performance can also be achieved for natural ore slimes through the combined technique. The efficiency is better than that of single gravity separation. Finally, the mechanism has been investigated.

Jan 1, 1990

By C. L. Schneider

The calculation of the liberation spectrum in the product from continuous milling operations is a problem of considerable importance and is difficult to solve because the population balance equation must be integrated in two-dimensional space. Complete solutions require the estimation of a large number of parameters unless a structural model of the ore texture can be used. A very simplified textural model based on the use of the modified Andrews-Mika diagram and the PARGEN simulation of multi-phase particles has been formulated and is used to simulate the behavior of a continuously operating laboratory ball mill. A sensitivity analysis for this mill has been done to show the likely effect of model approximations on the predicted liberation spectrum which will be measured.

Jan 1, 1992

By S. Su, S. Natansohn

This report describes a process for tungsten recovery from Searles Lake brines and upgrading its concentration to useful levels. The method consists of a combination of a liquid-solid and liquid-liquid extraction step and results in a product stream containing more than l00g W03/1. This technique is also effective in substantially reducing the concentration of objectionable impurities in the tungsten product. An ion exchange extraction mechanism is postulated.

Jan 1, 1983

By K. F. Unrug

Fractures of sedimentary rocks in the vicinity of the outcrop are commonly encountered around the world. Mine highwalls and numerous highway cuts give excellent views for detailed study of surface fractures. This paper gives an explanation of the origin of fractures as well as characterization of the distribution and extent of joint system with reference to lithologic composition of the rocks. Practical implications of the joint system affecting mine operations are described. Among the subjects discussed are: discontinuous deformation as an effect of surface subsidence, stability of mine portals and near outcrop underground operations, and stability of highwalls, when using highwall miners and strip operations. Some design procedures are recommended that can minimize the problems encountered in mining areas with intense joint systems.

Jan 1, 1994

By Yeonuk Choi, Gus Van Weert

cyanide control in effluents is becoming a critical environmental issue for the gold extraction industry. Silver impregnated carbon removes free cyanide effectively to the ppb level from solution in high throughput columns. By re-calcining the cyanide saturated carbon, the impregnated silver is restored to activity and the cyanide destroyed outside the effluent stream. Many gold mills already have an activation kiln on site, which could make retrofit relatively easy.

Jan 1, 1993

By R. Eggert

Since the discovery of high temperature superconductors has led to extensive interest and conjecture regarding their potential to change contemporary technology, discussions of the impact on the metallurgical and other industries have naturally arisen. In this paper we present data showing the possible impact of these developments on the materials related to the fabrication and proliferation of devices based on superconductor materials. We observe that the largest volume of effort with LTSC will be for the demonstration of high power devices while applied research relating to processing will remain the principal HTSC activity. We also note that in the next decade copper consumption in the US is expected to remain essentially at the current level while the need for Nb and Sn,; two major components of LTSC, will grow at a faster rate both in the US and the world. Although the use of superconductor-based magnetic separation is anticipated to increase, no major impact of these components on the metallurgical industries is expected.

Jan 1, 1990