Search Documents

By R. Mensah-Biney

The kinetics of gold-bromide loading onto activated carbon has been investigated in a batch stirred reactor. The amount of gold adsorbed by the carbon was correlated with time based on a second-order equation. The rate constant for gold-bromide species onto activated carbon ranged from 0.27 to 1.2 x 10-3 (kg/t)-l(min)-l from a solution containing 25 ppm of Au, with 0.8 g carbon per liter of solution at 30° C. The equilibrium saturation capacity (Q.) was 36±3.0 kg/t from the same system. The rate of loading increased with decreasing particle size, decreasing pH, increasing temperature, and decreasing concentration of gold in solution. The calculated activation energy E. was 8.8 kcal/mole, significantly higher than those reported for physical adsorption. The equilibrium saturation capacity (Q.) 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, 1996

By V. E. Housman

EPA's Mining Waste Section within the Office of Solid Waste is continuing to collect and analyze information on mining waste management practices. Starting in 1991, the Mining Waste Section has continued to conduct site visits and prepare case study reports on the waste generation and management practices of operating mines. In choosing sites to study, a reasonable attempt was made to provide diversity in mining commodity types, geographic regions, geology, climate, and environment. To date, EPA has visited the following mines: Asarco Troy (copper) in Montana, Newmont Rain in Nevada (gold), Cyprus Thompson Creek (molybdenum) in Idaho, LTV Steel (iron) in Minnesota, Phelps Dodge Morenci (copper) in Arizona, Doe Run Fletcher (lead) in Missouri, Brewer (gold) in South Carolina, IMC Four Corners (phosphate) .in Florida, Pennzoil Culberson (sulfur) in Texas, Nerco Cripple Creek (gold) in Colorado, Copper Range White Pine (copper) in Michigan, Magma San Manuel (copper) in Arizona, Colosseum (gold) in California, and several gold placer mines in Alaska, including the Valdez Creek Mine. EPA has prepared a case study report on each facility. The mine operators were provided an opportunity to comment on their respective site visit report and their comments have been included in' each respective report. These site visit reports have in turn been incorporated into technical resource documents which provide a detailed description of each mining sector. EPA is currently reviewing the technical resource documents and plans to release the documents in the Spring of 1994.

Jan 1, 1994

By D. L. Stevens

Following an in-depth scenario and strategic planning exercise in 1997, Noranda's mine production goal was set at 500,000 tonnes per year of both copper and zinc metal within five years. There had been no recent discoveries, reserves were shrinking and things had to be done differently and quickly. Change is now continual in our program but here is what we did first: Combined the exploration and business development groups Formed teams to search for and respond to opportunity Made our geologists more business minded and our engineers more optimistic Went global Set clear thresholds, farmed out the marginal properties, fast tracked the others Focused reconnaissance exploration where we had a clear competitive advantage Became a "flexible" partner to both juniors and seniors Is it working? A number of successes, near successes, and outright failures are discussed. The main result is a much higher rate of opportunity flux which is essential for success in the mining industry.

Jan 1, 1999

By T. Braun

A greenfield open pit gold mine in Latin America suspended operations less than three years into an eight-year mine plan after a waste rock dump and heap leach facility sustained substantial damage from a deep-seated landslide. No injuries to employees were recorded because of the slow-moving failure. Due to early detection by the operations team, the owner had sufficient notice of the potential failure and successfully rinsed the heap leach facility prior to the failure event. Engineers estimated approximately 35 million cubic meters of mass movement below the waste rock and heap leach facilities. The original eight-year mine plan produced approximately 60,000 ounces of gold per year. After the failure, the owner terminated gold production, re-configured the mine site to a safe, standby condition and launched a detailed investigation into the root-cause of the failure. Approximately two years after the shutdown, legal interests filed a statement of claim and named three engineering design firms and individuals involved in the project. Several years of litigation, including discovery and deposition proceedings, followed as the legal process considered evidence spanning a 20-year timeline. Changes in project ownership and consulting firms during the development and operations phase complicated the process. In 2017, the plaintiff and last defendant settled. The author was involved as the corporate representative for one of the engineering design firms.

Mar 2, 2022

By Robert E. Moore

Investigators have attempted to develop lime refractories on a scale for broad applications in the metal and ceramic industries for several decades. There was a flurry of activity in the early to mid-fifties but no commercial developments were forthcoming. The literature of that period yields little information on plant trials. A major factor suppressing past interest in lime has to have been the high success with the application of magnesic and dolomitic materials. These materials, usually tar-bonded or impregnated, have become the refractories success story of the past two decades, especially in BOF applications. It is safe to say that their development and application has essentially plateaued, and that work today is focussed on finding cheaper paths to produce MgO-based refractories. For example there are efforts underway to extract MgO from mineral magnesite and to combine natural dolomite with MgO1. Beginning in the late sixties, rather intensive research began on the development of CaO brick, especially in East and West Germany, in Poland, and other communist bloc satellites, 'and also in Italy and Spain. One speculates that the motivation was a regional shortage of good magnesia and dolomitic material. Of course, There has always existed the prospect of cost savings should it be possible to use raw limestone as the starting material. Quite a large literature has appeared treating of these developments which in the early seventies had already reached full plant scale trials and uses. Some of the directions followed in the research have led to novel methods of brick manufacture.

Jan 1, 1985

By Adrian C. Dorenfeld

[Agitation and transport of slurries have been investigated intensively for the past twenty years. It has been shown (1) that slurries have the properties summarized in Figs. 1, 2, 3, 4, and S. For a detailed exposition the reader is referred to the above reference and the bibliography, which, in turn, have extensive references and bibliographies. An interesting problem with which the senior author has been concerned with is the scab up of power requirements for slurry agitators operating in the laminar region with pseudo plastic materials. Pulps of shaly ores, after various chemical reactions in aqueous leaching systems, are often difficult to settle and filter if agitation is violent. In these cases agitation must be at a minimum, yet prevent [tling] such as in copper uranium ores. This mild agitation is on the laminar region.]

Jan 1, 1967

By R. S. Kinasevich

As part of other work related to the studies of kinetic factors that influence the flotation of specific sulphide minerals, specially designed kinetic flotation experiments at Cominco included work done on -65 + 100 mesh and -100 + 150 mesh, high purity galena. The flotation collector used was sodium isopropyl xanthate containing radioactive sulphur-35. Radiation monitoring of the galena fractions from stage flotation tests indicated that the adsorbed radioactive xanthate was uniformly distributed among the floated fractions and the non-floated, or residual portion of the galena. This anomalous behaviour could not be correlated to changes in Seebeck coefficients, to lattice distortions, or to the nature of the mineral surface as revealed by infrared spectroscopy and by microscopic measurements.

Jan 1, 1970

By V. P. Keran

Design of the Bajo de la Alumbrera Project started in June 1995 and concentrate production commenced early in the Third Quarter of 1997. The project is situated in North-Western Argentina and is being developed by Minera Alumbrera Limited which is owned by MIM Holdings Limited of Australia (50%), North Limited of Australia (25%) and Rio Algom Limited of Canada (25%). This paper outlines the key features that were incorporated in the design from both process and plant layout perspectives. It explains the background of flowsheet and equipment selection for the plant. A feature of the flowsheet is that it incorporates gravity gold circuits in both primary and regrind circuits for recovery of gold to dore as well as in the copper concentrate product.

Jan 1, 1998

By Willard C. Lacy

INTRODUCTION A program to insure adequate talent for development and management of our mineral resources entails two equally important and interrelated aspects: 1) attracting and retaining promising student talent, and 2) providing a first-rate education for those entering careers in mineral science and engineering. Manpower shortages have eased in many areas of engineering, particularly in those areas dependent directly or indirectly upon government contracts in space and war programs. However, in the minerals industry the needs still remain critical. As increasing concern over preservation of the environment has developed, the political and social reaction was to seek out major offenders, to look for "whipping boys" -- and the mineral industry was, and had been, an offender. It was there for everyone to take pictures, it couldn't be covered up, and the Department of the Interior lashed away in the beautiful and popular brochures: Quest for Quality, The Third Wave, The Population Challenge, and Surface Mining and Our Environment (Ravaged Land). The Sierra Club, the Field and Stream magazine, TV, and daily news media added their lashes. In the minds of our social-conscious youth the mineral industry took on the image of "exploiters" of natural resources; "polluters" of streams, lakes, and the atmosphere; "despoilers" of wilderness areas and scenic beauty -- a plague to combat, rather than an exciting challenge that entailed exploration of the remote, conquering of the primitive, and developing of the undeveloped. Enrollments declined and many traditional mineral engineering curricula were abolished or Integrated into other stronger engineering departments to meet student-faculty ratio requirements.

Jan 1, 1971

By R. R. Cellan

There have not been many opportunities to date for comparison between laboratory and commercial neutralization rinse data. Homestake Mining Company's Santa Fe project is one such comparison. This paper discusses laboratory procedures and results from a 100' leach pad height simulation column neutralization rinse test and compares principal data with that achieved in actual commercial leach pad neutralization rinsing procedures. Principal comparisons include the rate of WAD cyanide neutralization, decrease in effluent pH, stabilization of dissolved silver and copper, and the quantity of dissolved gold recovered during rinsing.

Jan 1, 1996

By G. K. Hoffman

Humate, defined as weathered coal or mud-stone rich in humic acid (HA) and fulvic acid (FA) have been mined, primarily as soil amendments or drilling mud additives, in New Mexico for 15-20 years. The New Mexico humate resource is estimated to be 11 Gt, including weathered coal and organic mudstone. The HA and FA content determines the end-use, therefore a simple and consistent method of measuring organic-acid content was developed. The New Mexico Bureau of Mines and Mineral Resources method is based on repeated alkali leaching and acid precipitation. Precipitates of humate are ashed, with mass balance of solids maintained, to correct for material added during alkali-acid treatment. Analyses of upper coal member, Cleary Coal Member (Menefee Formation) and Fruitland Formation samples from the southeast San Juan Basin show ashing to be important in accurate analysis of FA content. Ash in the total FA fraction averages 70% compared to 2% in HA. The FA in weathered coal and organic mudstone are similar, although HA is significantly higher in the former. As weathering progresses, the FA content of weathered coal increases faster than in organic mudstone because of the greater total organic material in coal.

Jan 1, 1994

By Ali Ekrem Aritan

Exposure to hand-arm vibration (HAV) among the labor force in the mining industry can result in permanent vibration diseases such as behavioral disorders, visual impairment, osteoporosis, pain (mostly in the hands, wrists, and shoulders), circulatory system disorders, and malnutrition. In this study, the vibration exposure of excavator operators working regularly in 25 different natural stone quarries was measured. In addition, the relationship between vibration exposure and rock properties was investigated. Gloved and ungloved vibration measurements were performed and revealed that antivibration gloves reduce excavator operators’ vibration exposure by 7.10–25.95%. Samples from each quarry were characterized with rock mechanics tests. The correlations between the hand-arm vibration measurements and the natural stone physical–mechanical properties (uniaxial compressive strength, Shore hardness, Knoop hardness, apparent density and total porosity) were determined to be over 70%. One finding of the study was that the health risk in excavators cannot be reduced sufficiently by the sole use of antivibration gloves. Furthermore, the excavation of any rock with a Knoop hardness above 121 is associated with an 81% risk of HAV. To increase awareness of the danger of vibration exposure for natural stone miners, training programs should be provided, and technical and operational changes should be implemented.

By X. Baolin, R. Guru, M. Peiravi, M. K. Mohanty, Z. Qian, R. Ma, Z. Yude, L. A. Ackah

"Acid mine drainage (AMD) is produced when exposed pyrite (FeS2) reacts with air and water to form an acidic solution that usually contain contaminant levels of heavy metal ions. AMD can potentially contaminate surface water and soil if not treated. The primary objective of this study was to investigate the removal of dissolved aluminum, iron and zinc metal ions from natural AMD using water treatment residue (WTR), a low-cost adsorbent. WTR sorbent generated as waste material in drinking water treatment plants (WTP) was characterized and utilized for the sorption of Al, Fe and Zn in AMD collected from an abandoned coal mine site in southern Illinois that generates approximately 20 gallons per minute of AMD. Sorption experiments were performed using batch technique to obtain rate and equilibrium data. The effects of various parameters on sorption capacities of WTR were observed by varying contact time, pH of the AMD and WTR dosage. The adsorption studies showed rapid uptake in general for the first 80 minutes for Fe and Zn but much earlier for Zn. Further increase in contact time did not show significant change in equilibrium concentration indicating the onset of adsorption equilibrium. After the batch treatment of the AMD water with the WTR, the removal of Al, Fe and Zn were 99.8%, 99.85% and 95.5% respectively. The pH of AMD increased from 2.64 to a near neutral point of 6.74 after treatment. The laboratory results show that the low-cost WTR, which is an abundantly available industrial waste, has proven potential to significantly reduce the high metal ions in acid mine drainage. INTRODUCTION Mining activities provide the basic raw materials needed for infrastructure development and economic growth world-wide. However, it is well recognized that mining activities have been the cause of a variety of environmental pollutions, including AMD. Water seeping out of an old abandoned mine is generally characterized by low-pH with heavy loads of dissolved sulfates (SO4) and metal species such as Fe, Al and Zn among other dissolved elements categorized as toxic metals. The Bureau of Land Management’s Abandoned Mine Lands (AML) program reported the existence of about 46,000 abandoned mines in the United States. Several environmental problems have been reported to be associated with these mined out sites such as heavy metal poisoning, loss of vegetation, air pollution etc. (Boulanger & Gorman, 2004)."

Jan 1, 2017

By Mohammed Laraba, Rodrigo Alvarez Garcia, Juan Maria Menendez-Aguado, Roula Abdelmalek

The aim of this research is the study of the WHIMS parameters on the improving process of a local (DD: Djebel Debbagh, East of Algeria) kaolin. The obtained results of performed XRF, SEM, and XRD characterization showed that this local material is an alumino-silicate containing kaolinite and halloysite with MnO and Fe2O3 impurities (respectively 39.30% and 34.67% alumina and 38.18% and 39.70% silica in both samples (DD2 and DD3). After homogenization, crushing, and milling, a multiparameters factorial experimentation (grain sizes, intensity, and dimension of matrix balls) showed that WHIMS is an effective process to improve the quality of this kaolin, mainly: removing their impurities. Dimensions of matrix balls (Db) = 2 cm, intensity of the applied magnetic field (I) = 1.5 T, and grain sizes (Dp) = > 100 < 250 μm) are the optimal values to reach 91.06% for manganese and 93.45% for iron as removing yield. The statistical analysis of these results sorted the investigation parameters and showed that Db has the highest and most significant influence on the recovery of iron and manganese particles. The magnetic field intensity (I) has a less important influence while the grain size has an average influence (positive on the iron recovery but a negative one on the recovery of manganese).

Jun 11, 2022

By B. F. Dickerson

STRATEGIC METALS! Recently, this money accented cry has been heard in such diverse locales as Mining company boardrooms, Banker&apos;s offices, Stockbroker&apos;s quarters, Swindler&apos;s dens and Congressional committee rooms. (In some cases, these locales are one and the same). Is the strategic metals rush for real? Should it be? Our paper attempts to give a very generalized view of the subject for a few metals, points to a few potential, but generally overlooked sources of these metals, and offers conclusions based on our studies.

Jan 1, 1981

By Charles R. Marek

There is an ever-increasing need for quality construction materials to provide the necessary housing and transportation facilities required for the protection and movement of people and goods. By the year 2000, requirements for housing in the United States will have doubled due to population growth. Requirements for transportation facilities in this same period will also have increased substantially. Further, all existing facilities for both housing and transportation will require substantial maintenance of one form or another. Aggregate is the basic material of the construction industry. There is some occurrence of aggregate source material in virtually every state of the United States, and in every country in the world. United States reserves of commercially useable aggregate have never been systematically estimated and are probably so vast as to be incalculable.1 However, in many areas its existence is largely negated by inaccessibility. Often it is lodged deeply or intricately in the earth or it is too distant from markets to offer a desirable "return on investment" under the present economic structure. Other factors that prevent its utility are the occurrence of small scattered deposits that individually are too small to justify the necessary capital investment for exploitation and collectively are too widely disseminated; also, the aggregate nay be deficient in certain desired chemical or physical qualitites.1

Jan 1, 1974

By Martin H. Stanczyk

In recent, years the demand and consumption of finely ground industrial minerals has substantially increased for such uses as fillers and chemically reactive components. The size, specifications for these types of industrial mineral materials vary to a great extent and depend on the particular end purpose&apos; and on the physical properties of the mineral itself. Size reduction of industrial minerals usually is obtained by conventional crushing and grinding methods. However, some specialized milling techniques have been developed for producing these minerals in extremely fine particle size ranges. During recent years the Bureau of Mines has been investigating an attrition grinding method to produce ultrafine subsieve-size mineral particles. The Bureau developed process, which has been patented,2 comprises the intense agitation of a slurry composed of the material to be ground, a relatively fine granular grinding medium, and a suspending fluid. The process has been shown to be effective for the comminution of kaolin in the particle size range of 2 microns and finer on a batch3 and continuous basis.4,5 This report presents the results of batch tests made to determine the effectiveness of the attrition grinding process for comminuting commercial products of (1) mica, a tough lamellar material, (2) fluorite, a brittle intermediately hard material, and (3) barite, a relatively soft, massive material.

Jan 1, 1967

By Anthony Edey

It is a generally accepted and widely discussed fact that the world in general, and the United States in particular, face a shortage of energy at the present time which will become worse in the future. There is, however, no sign of a similar concensus as to the actions which would prevent or overcome this expected shortage. An immense variety of solutions has, however, been put forward, ranging from the purely political to the outer fringes of sophisticated technology. One resource which surprisingly is often only cursorily included in this discussion is the immense known petroleum reserve lying within the United States. When this subject is discussed, indeed, it is usually in the context of the improvements in production or new discovery rate that could be expected to result from possible politico-economic actions that would raise the real price obtained for domestic crude. This interest in the potential for improved domestic production is undoubtedly justified, but very little attention is normally drawn to the fact that even under the most favorable policy framework the majority of the oil that has been, or will be, discovered will remain in the ground due to the inherent limitations of production through surface wells.

Jan 1, 1979

By Robert D. Thomson

The plastics industry runs into the billions, both in the dollar value of its finished, products and in the pounds of plastic raw material produced. It is, too, one of the fastest growing industries with a 300 percent increase in production in the past ten years. Informed estimates set 5.9 billions pounds as the plastic volume for 1959. Statistically, this is equivalent to a per capita consumption of 25 pounds in the United States. Plastics are man-made materials in contrast to natural materials like wood and are a family of materials -- not a single material - each member having special advantages. A generally accepted definition; for plastics is; a large and varied group of materials which consist, wholly or in part, of combinations of carbon with oxygen, hydrogen, nitrogen, and other organic and inorganic elements. This, while solid in the finished state, at some stage in its manufacture is soft enough to be formed into various shapes, most usually through the application either singly or together of heat and pressure. Many combinations and many different materials are thus possible. Therefore, for purposes of simplification, most plastics can be classified under one of 14 recognized basic family groups. These groups in turn generally can be further classified into one of two major subdivisions - thermosetting or thermoplastics. A few plastics are in between and they can be formulated to be either thermosetting or thermoplastic.

Jan 1, 1960

By P. A. Cornejo

Blastings always generates induced vibrations through seismic wave, these are lost energy from the blasting and therefore causing the disturbance of slopes and structures near the blast source. Most of the components of an open pit mine have to reach a physical stability, especially during its closure process. Aiming to develop a vibration prediction model using the historical records from an open pit mine located on Peru, this research has two main focuses depending on the distance from the blast source to the structure: to protect the final slopes and to protect the villagers houses. Both are based on the Devine model of the Square Root Scaled Distance (SRSD) to predict the Peak Particle Velocity (PPV). The Mid field model, where is found mainly final slopes from the pit, limited by the failure criteria of McKenzie based on the geo mechanical properties of the rock mass. The Far field model ranges distances where are located the most community households, limited by the German rule DIN 4150 for highly sensitive structures. Both scenarios resulted on a distribution abacus to limit the weight of used explosives to get the best operational advantage and structure safety.

Mar 2, 2022