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By Craig J. Brown

Despite its great potential utility, ion exchange has only achieved limited application in hydrometallurgy. To a significant extent this is due to the limitations of conventional ion exchange process design as well as the properties of the ion exchange resins themselves. Over the past decade several new ion exchange resins have been introduced with properties that make them potentially very useful for various hydrometallurgical separations. In addition, a novel ion exchange process called Reciprocating Flow Ion Exchange or Recoflo, which has been employed in the metal finishing industry for the last dozen or so years for chemical recovery and effluent treatment, has been shown to offer a number of unique and significant advantages over conventional I.X. technology.

Jan 1, 1984

By Ray W. Ballmer

Historically, Bingham is a rail pit, starting with steam locomotives in 1906 and converting to electric locomotives in 1923. Ore production was maintained through an effective utilization of available rail equipment. From time to time as it became necessary to deepen the pit and as stripping ratios increased, various studies were made on alternate material haulage systems. Utilization of diesel locomotives, conveyor belts, and trucks have all been subjects of study, however, conversion from rail haulage utilizing electric locomotives could not be justified. Because of the gradual decline in ore grade, a program was approved in 1963 to raise ore production to 108,000 tons per day. This was designed to return copper production to the 1950 level. Attainment of this production level by expansion of the rail system had definite limitations and built-in inflexibility. Track and trolley wire relocation causes shovel down time in excess of that required for normal maintenance. Instability of the dumps and the resulting additional track maintenance increases greatly as the volume of waste material to be handled daily expands.

Jan 1, 1965

By W. A. Zingg

Impervious zones in copper waste heaps create a problem in contacting the rock with leaching solutions. These zones are normally associated with compacted layers .formed on the surface of each lift by dump truck traffic and by disintegration of the rock exposed to atmospheric conditions. These layers are usually only a few feet in depth--but, nevertheless, act as barriers to vertical flow causing the leach solution to perch in the heap, Consequently, much of the rock remains untouched and the leach solution breaks out the side of the heap instead of continuing downward to bedrock. One solution to this problem is breaking the hard pans with explosive charges. However, to use explosives means adopting new explosive materials and methods. To use this process successfully requires finding answers to operating conditions inherent to waste heaps. Foremost among these are: (1) type and size of casing that can be used because of limitations brought about by drilling problems, caving and, corrosive conditions; (2) perforating the casing at required levels; (3) an explosive capable of being pumped; (4) obtaining detonation of the, main charges through, the wail of the casing; (5) an explosive with the ability to propagate through the voids of the rubble and one which is not affected by water, acidic solutions, or back pressure conditions from hydrostatic heads; (6) to heave and rupture the compacted zones without chambering or recompressing the waste material.

Jan 1, 1970

By H. B. Trinh, R. R. Srivastava

"Spent auto-catalyst is a potential secondary resource because of the higher concentration of valuable platinum group metals (PGMs) as compared to the primary ores. Despite the well-developed commercially tenable technologies, further researches are being carried out to extract the PGMs with high efficiency. It is however, critical in this context to reuse not only the PGMs but also other metals contained in the spent auto-catalyst particularly that of the cordierite substrate such as aluminum, magnesium and cerium oxide (CeO2). This is important in view of the fact that no recycling process has ever stressed upon the recovery of cordierite substrate and CeO2 since the main target metals are mostly the PGMs. In this study, a new hydrometallurgical approach has been proposed in order to recover the PGMs as well as cerium oxide and materials from the cordierite substrate by using sodium hydroxide roasting followed by sulfuric acid dissolution. Under the optimal conditions for roasting at above 600°C, and weight ratio of sample to NaOH of 1:1 for 60 min, the cordierite was converted to the soluble phases. Dissolution of the roasting products using H2SO4 solution (1M) at 25°C for 60 min enriched the PGMs and Cerium oxide contents in the residue. Subsequently, PGMs in solution after dissolution can be cemented using Al and Cerium oxide in residue can be recovered by hot digestion using concentrated H2SO4.. INTRODUCTION Auto-catalyst can significantly control the gaseous emission of automobiles, and has been considered as a potential secondary source of Platinum group metals (PGMs) after being decommissioned from the vehicles. The PGMs demand is continuously increasing to comply with the growing vehicle population and the tightening of emission standards all over the world; meanwhile the natural resources of these metals is facing the threat of depletion. Therefore, it is crucial to progressively substitute with an alternate resource to supply PGMs other than that of the primary ores. Nowadays, vehicular transportations worldwide are totally installed with the auto-catalysts. However, they should be replaced after reaching their service life. If there is no recycling of such resources, huge amount of valuable metals will be wasted. The quantity of PGMs that can be recovered from the spent auto-catalyst depends on the size of car, which averages to 1-2 grams for small cars and 12-15 grams for the big truck; this is significantly higher than that of the primary ores containing 2-10 grams PGMs per ton. Consequently, the recovery of PGMs from spent auto-catalyst becomes extremely favorable as compared to the primary resources due to higher concentration of PGMs, with much lower and simpler processing steps, and lesser pollution."

Jan 1, 2018

By N. D. Cristescu

The aim of the present paper is to show how a mathematical modeling of a creeping rock and that of an yieldable lining can allow us to obtain an optimization of the lining design and generally of the whole procedure and sequence of excavation-lining application. We follow the procedure presented by Cristescu (1989) Chap. 13, and Cristescu et al.(1987); for some other approaches see the literature mentioned, for instance, by Ladanyi and Gill (1988). We have in mind to describe the creep of the rock, i.e. the tendency of the tunnel to close in time, and to take into account that the lining itself may be deforming, i.e. possesses some rheological behavior. We start from the well known fact that "intelligent" lining, which are yielding to the pressure of the rock, may be much more successful in supporting creeping rocks than excessively strong, badly designed supports which are unable to resist to pressure of the rock, though these are oversized supports (too strong, too stiff, installed too early, etc.). In order to optimize the lining to be used for a certain rock, it is absolutely necessary to study in the laboratory the main mechanical properties of that specific rock and to formulate for it a reasonably simple mathematical model. Standard triaxial test results are quite enough to determine the model for the rock, combined with some creep tests which have to reveal the long-term behavior of rock (the so-called rheological model). What concerns the lining, we consider several kinds of linings existing today, for which a mathematical model was also formulated. One shows which is the interaction between the creeping rock? and the yielding lining and how can it be formulated in mathematical terms. Once written in mathematical terms, an optimization of the lining design and that of the excavation layout and support application sequence is possible. We will try to make the exposure as simple as possible, avoiding details and having in mind to give only a sketch of the problem, while the mathematical details could be worked out quite easy.

Jan 1, 1994

By JÖRG DEHNERT, PETER WINDISCH, Bernd Schönherrt, JENS STOPP

The Quick-Erect Stopping System (QESS) offers a new way of reducing the radon exposures of miners in Germany, especially during remediation work in old mines. The QESS is a light-weight, modular, and reusable construction kit of interlocking telescopic aluminum tubes, radon-proof foil, and expanding foam. It is designed to seal off radon-rich parts of galleries within only a few minutes. Originally, the QESS was developed to protect miners against radon exposures. Then, the QESS found the attention of several mine rescue teams at a German mining conference. The Student Mine Rescue of the Technical University Bergakademie Freiberg and the Wismut Mine Rescue carried out firstmine rescue drills in Freiberg and Schlema. Additionally, a mine rescue drill was carried out by the Front Range Mine Rescue in the Edgar Experimental Mine of the Colorado School of Mines. These drills helped to improve the systemand highlighted its potential for mine rescue operations. Now, the QESS is wellsuited for small-scale mining. The QESS can be used to seal off galleries in only a few minutes to both protect miners fromradon exposures and to support mine rescue operations. Moreover, the QESS was also successfully used in ventilation experiments.

Jul 23, 2020

By W. A. Mathews

We report on the progress of an automated mineralogical deportment of fluorine (F) in two portions of the Grasberg District for the development of metallurgical amelioration protocols for Cu sulfide concentrates. Fluorine detection limits in automated SEM technologies range from 1% (TIMA) to about 9% (QEMSCAN), however substitution in hydrophobic minerals or those reporting to concentrate is typically much lower (

Mar 2, 2022

By M. J. Beus

Technology to enhance safety during mine hoisting has been developed by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Assessment of current hoisting technology suggests that monitoring conveyance position and load directly from the skip or cage top offers several significant safety advantages. Wireless data transmission schemes and a package consisting of sensors, batteries, and a charger mounted on the wire rope and skip have been developed. A state-of-the-art automated hoisting test facility was constructed to test the concept in a controlled laboratory setting. Field tests in a full-size shaft are underway.

Jan 1, 1999

By James L. Kelley

The Twin Buttes Mine, one of the more recently developed large copper mines in the United States, is in the Pima Mining District about 25 miles south of Tucson (Figure 1). Other copper producing mines in the district are the Esperanza-Sierrita mining operations, five miles to the southwest and the Pima and Mission Mines, seven miles to the north. Copper metal production from the Pima District in 1974 totaled 276,728 tons and the Twin Buttes Mine's share was 46,473 tons or about 17%.' The district's copper production was 31% of Arizona State's production and nearly 17% of the production from the United states in 1974. The Pima District thus ranks as one of the major copper producing areas in this country.

Jan 1, 1976

By S. R. Hutchins

Several refractory sulfide and carbonaceous gold ores were examined to determine whether microbial pretreatment could be used to enhance gold recovery. Test samples were biologically leached using unique, thermophilic microorganisms to solubilize iron sulfide minerals. Gold recovery from sulfide ores and concentrates was enhanced following pretreatment with the thermophiles; responses varied widely for the individual materials. Although bioleaching had little effect on the preg robbing characteristics of the carbonaceous gold ores, cyanidation of the bioleached residues yielded higher gold recoveries than cyanidation of the native ore. By combining bioleaching with abiotic processes designed to inhibit preg robbing, gold recoveries of 83-98% were obtained from carbonaceous ores yielding 10-50% gold recovery by direct cyanidation.

Jan 1, 1987

By K. F. Unrug

The identification of the major subsidence areas in the Western Kentucky Coal Field has been made to distinguish the subsidence phenomena on the basis of geographical location Further, this identification process is based upon selected critical geological, topographical, and mining features in the coal fields. The proposed identification of the regions is derived from a comparison of the subsidence potential in a particular area. The most likely severe subsidence areas are compared to those with the probable low subsidence severity. The combination of certain geological and mining parameters involved allows for the derivation of a classification of the subsidence potential. It is recommended that further site specific studies should be performed on this area.

Jan 1, 1986

By James J. Scott

Shale formations are the Nemesis of the Mining Engineer. Shales react to changes in environment in the most unusual and unpredictable manner. Increase in temperature may cause spalling, increase moisture and compression induced fractures may occur, and if a full face is exposed it may deteriorate due to atmospheric exposure. Combine only small amounts of shale in layered fashion with hard brittle competent rock and the whole structure may be fractured and fail due to stresses generated in and around the shale. In this paper the author will discuss failure mechanisms encountered under various field conditions and remedial action which may be employed by the engineer.

Jan 1, 1969

By P. S. Sundar

A laboratory method for the simulation of in-situ leaching of uranium was developed under contract to the Interior Department's Bureau of Mines. Simulation tests using sulfuric acid, ammonium bicarbonate and sodium carbonate as reagents and hydrogen peroxide as oxidant were carried out with representative ores from Texas and Wyoming. The tests not only yielded recovery rates of uranium and permeability changes, but also qualitative inferences on the chemical and physical phenomena which occur underground. Leaching with basic solutions was found to be kinetic constrained and with acid solutions, equilibrium constrained. The rapid permeability changes observed when leach solutions were introduced, were probably caused by gas blockages in the packing. Precipitation of calcite or gypsum and the reaction of clay to leach solutions had slow and gradual effect on the packing permeabilities.

Jan 1, 1978

By R. H. Bartlett

Hydrometallurgical processes for copper flotation concentrates avoid the S02 emission problems associated with smelting, but they require oxidation of copper to obtain solubilization during leaching. The resulting copper ions must be reduced to metal, which normally requires large amounts of energy or energy equivalent reagents such as hydrogen or iron. The conventional reduction method is electrowinning which is labor intensive and involves 35 to 40% of both the en-tire operating and capital cost of the better hydrometallurgical processes. Smeltermen are correct in criticizing the available hydrometallurgical processes for being more energy intensive than modern smelting processes. Clearly, there is considerable incentive to reduce the cost and energy required for reducing copper ions from solution. Furthermore, it is thermodynamically possible to do this using sulfur contained in the concentrate itself. In fact, the thermodynamic potential of oxidizing sulfur from S+4 to the S+6 state is greater than required to reduce cupric ion to metallic copper. (1) Realization of this potential in a practical process would significantly reduce the cost of hydrometallurgical processing of sulfide concentrates because sulfur would become a cost-free reducing agent. An apparently practical method is to use SO3 and HSO3 ions, obtained by ammonia scrubbing of SO2 from a concentrate roaster gas, to reduce leached copper to metal in an autoclave. This reduction step is the Jumau 1907 patent. (2) A series of steps including sulfite reduction constituting a crude flowsheet was suggested by Parker in 1976(3), but apparently little development work has been done by him, since he has been interested in new routes of refining the resulting copper powder. The purposes of the present paper are to elaborate on the Jumau-Parker thrust. Describe a detailed complete sulfite process flowsheet based on materials and energy balances, discuss the chemistry, and discuss further work that is required to develop this process. The results of the present paper are largely based on a synthesis of the steps using handbook chemistry. Process materials, utilities costs, and energy requirements are projected to be unusually low.

Jan 1, 1978

By Maurício Covcevich Bagatini, Maycon Athayde

Water consumption reduction in pellet feed operation is of paramount importance. Compared with traditional ball mills, high-pressure grinding rolls (HPGR) play an important role in Blaine surface area (BSA) generation to improve agglomeration properties, although stability is still a challenge. Grindability improvement of existing operation has a direct impact on the performance of the filtering and pelletizing operation. The results of this study, as a pregrinding operation, can be applied not only in new operations but also in existing ones, helping the operator control process variation in a more effective way while ore hardness increases. 

By L. B. Phelps

Many coal mining companies have potential surface mine reserves which either are known or suspected to have had prior drift mining activity on them. In many cases, there is no documentation on these mines or at best, very fragmented records. These undocumented abandoned underground mines are creating engineering, financial, and environmental difficulties and concerns for both surface coal mine operators and regulatory personnel. This paper examines the use of resistivity techniques in detecting entries of abandoned drift coal mines. The detection of such a drift mine entry would confirm the presence and orientation of an abandoned underground coal mine.

Jan 1, 1985

By Clarence O. Babcock

A simple robust rock bolt load gage was tested in the laboratory to define its characteristic behavior and to obtain a measure of its performance. The gage uses three vibrating wire sensors crimped 120 degrees apart into the outer surface of a hollow cylindrical steel tube. The resonant frequencies of the wires change as the gage is loaded. This change is read with a Creare meter developed for the Bureau on a previous contract to read borehole stress gage results. A statistical analysis of data obtained defines the variables influencing results. A U. S. patent (3,914,992) assigned by the author to the Department of the Interior was granted October 28, 1975.

Jan 1, 1976

By Amir Karami, Scott Munro

This paper focuses on remediation of a 3.6 km long water conveyance tunnel that suffered two large falls of ground (FoGs), one of which subsequently progressed to the ground surface, resulting in full collapse of the tunnel. The tunnel is part of a network of water conveyance tunnels and open channels that direct water into two turbines located in an underground powerhouse, originally constructed in the 1970s. At the time of construction, the tunnel was partially supported with shotcrete or rock bolts, with no further ground support added since construction. Two sonar surveys in 019 and 01 identied two adacent large FoGs in the tunnel, approimately 1.2 km from the tunnel outlet. Historical geological and geotechnical information indicated that the FoGs occurred within a 60 m wide fault zone. Remediation plans were developed, which included stabilization of the outlet channel, the portal, the tunnel leading up to the FoG areas (1.2 km length) and the FoG areas. Several remediation options were considered to restore the tunnel, including construction of a diversion tunnel to bypass the FoGs or remediation of the FoG areas with steel ribs and backlling the void above the FoGs to surface.

Jun 23, 2024

By A. R. Rule

As part of the Federal effort to help maintain an adequate supply of fertilizer minerals, the Bureau of Mines is conducting research to characterize complex, low-grade western phosphate rock and to develop methods for economic recovery of phosphate. The rock varies from soft, friable, altered phosphatic shale to hard, tightly cemented, unaltered phosphate rock. To supplement current beneficiation by sizing, a flotation procedure was devised that included depression of phosphate minerals with H2SiF6 and anionic flotation of carbonate minerals, followed immediately by cationic flotation of silicate minerals. Application of the procedure to several different ores resulted in phosphate concentrates that ranged from 28 to 31 pct P20S in grade and from 60 to 70 pct in phosphate recovery.

Jan 1, 1977

By J. C. Cawley

Improvements in today's maintenance practices are mandatory as more complex and productive machines evolve in the mining industry. By keeping machine reliability high, through improved maintenance procedures, overall mining costs can be reduced. The Bureau of Mines is investigating diagnostic maintenance systems for underground mining machinery. A hydraulic expert diagnostic system and an electric motor predictive diagnostic system have been designed and installed on a Joy 16CM continuous miner. An electrical diagnostic system has been designed and installed on a Joy 14CM continuous miner. Each system is functionally described and the relative merits of expert diagnostic systems versus algorithmic diagnostic systems are discussed.

Jan 1, 1991