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By R. Bhaskar

The objective of the project was to optimize the ventilation parameters of a continuous miner underboom scrubber to further control. the amount of airborne dust discharged during mining, to further reduce the exposure of face personnel for an exhaust brattice ventilation system, and avoid recirculation of contaminants at the face. This research was performed in an underground coal mine in Utah. The tasks included preliminary face ventilation evaluation and optimization of the scrubber system to eliminate recirculation of the scrubber discharge air. Airflow tests were conducted on the currently used dust control system and the modified scrubber system. Tracer gas tests were performed to evaluate face ventilation effectiveness. Confirmatory tests of the scrubber system under actual operating conditions, modifications to the scrubber system, and a comparative evaluation of the scrubber system vs. the existing system were performed. This paper presents the results of the airflow pattern tests and the respirable dust levels in the modified scrubber system and the existing system. The optimized face ventilation parameters and the developed operating guidelines may provide the benefits of dust reduction, better face ventilation, and improved visibility.

Jan 1, 1994

By Corale L. Brierley

The effect of hydrogen peroxide (H2O2) on growth and respiration of Thiobacillus, thiooxidans, and Thiobacillus ferrooxidans, organisms involved in acid leaching of copper sulfide minerals and uranium oxides, was examined. Oxygen uptake and growth by T. thiooxidans were inhibited after contact with 0.82 mM H2O2. Inhibition of oxygen uptake by T. ferrooxidans occurred at 8.24 mM H2O2, and growth was inhibited after 6 hours exposure to 2.06 mM H2O2. Higher concentrations of H2O2 can be used without detriment to thiobacilli if it is dissipated prior to reaching the oxidation pond or dump surface. INTRODUCTION In recent years, hydrometallurgical processes for recovery of metal values from low-grade ore minerals have played an increasingly important role. Dump leaching of low-grade copper waste materials in the western United States now yields 11.5% of the total U. S. copper production. Although scavenger operations in uranium leaching have been successful, the state-of-the-art of in-situ

Jan 1, 1977

By J. G. Groppo

Eastern U.S. oil shale contains approximately 10 to 12 gallons of oil per ton and 7 to 10 percent pyritic sulfur. Physical beneficiation of these low grade shales using froth flotation provides a high grade material which will make extraction of oil more economically attractive. The Alabama oil shale used in the present study contained 16.46 percent organic carbon and 14.5 gallons of oil per ton as determined by Fischer assay. Liberation size of the kerogen was estimated at 10 /-Lm. 'Ken-Flote' column flotation technology provided a high grade concentrate containing as much as 60 percent organic carbon, however, carbon recovery was about 60 percent. Carbon recovery was improved to 75-85 percent while maintaining concentrate grades in excess of 40 percent carbon by providing longer retention time in the column which facilitated effective bubble-particle collision and attachment.

Jan 1, 1993

By M. Guzman, M. Romero, S. Bravo-Thais, M. Flores

The phytoremediation method is proposed to recover valuable metals from polluted soils. In this sense, the objective of this research is to determine if it is possible to use native plants in the recovery of precious metals from abandoned mining liabilities. The tailings samples containing Au and Ag were acquired from the northern region of Peru. Two native plant species, Stipa Ichu and Cortaderia Nitida, were used. Results show that Au was recovery around 19% (1.52 mg/Kg) and 25.43% (1.78 mg/Kg) by using Stipa Ichu and Cortadeira Nitida, respectively. Besides, Ag had a better recovery in the Stipa Ichu reaching a value of 6.83% (0.628 mg/Kg); in contrast, Cortadeira Nitida had an efficiency of 3.6% (0.814 mg/Kg). Bioaccumulation, bioconcentration and translocation factors were calculated by determining the concentration of precious metals in the roots and aerial parts of each plant. Results show that Stipa Ichu had a greater capacity of hyperaccumulated Ag compared to Au; while Cortaderia Nitida tended to have a better performance for Au. In conclusion, both plants are recommended for phytoremediation of mining liabilities.

Feb 1, 2023

By Jerry G. Rose

This paper addresses a process by which both the disposal and utilization of preparation plant coal refuse can be simultaneously accomplished with an attendant benefit of significantly increasing the percentage of extractable coal. A laboratory study is described in which coal refuse was successfully utilized as an aggregate in low cost concrete (coal-crete) mixes under simulated mine environments. Coal-crete specimens with compressive strengths of 14,000 kPa (2,000 psi) were consistently produced. A construction sequence and mining plans are offered for placing the low-cost coal-crete pillars in accessible areas in room-and-pillar mines so that a Substantial portion of the remaining coal pillars could be extracted. The method could be applicable in areas where mining procedures do not permit pillar extraction because of possible surface subsidence, roof problems, or other conditions. Possible structural difficulties with the coal-crete pillar support system are discussed. Using a discounted cash flow analysis, the economic feasibility of mining with the coal-crete pillar system is investigated. The cost of the coal-crete pillar system is compared to the cost of a mining system which would have less coal recovery. The analysis indicates that although at higher coal selling prices the coal-crete mining system may yield an acceptable rate of return, the alternative of leaving the coal pillars is more attractive at the present time.

Jan 1, 1977

By S. Behl

A major limitation in developing successful selective flocculation schemes is the difficulty encountered in adsorbing the polymeric flocculant only on the desired substrate. In this paper a correlation between selectivity of flocculant adsorption and separation efficiency is outlined and a potential technique to achieve selective adsorption of flocculants is discussed.

Jan 1, 1992

By R. M. Quinlan

The coal industry in the United States has undergone significant economic changes during the past six years. The price of coal remained relatively constant from 1950 to 1969 (See Figures 1 and 2). Steam coal prices tripled and metallurgical coal prices doubled from 1969 to 1974. This price structure has created a new economic environment for coal preparation. Contributing factors to these price trends include: ? Coal Mine Health and Safety Act of 1969 ? Mid-East oil embargo of 1973 ? United Mine Workers of America contract agreements ? Productivity decrease (tons per man-day basis) ? Environmental Protection Agency regulations The increased value of coal justifies additional capital investment in cleaning facilities to optimize yield. Current trends include recovery of existing slurry ponds and recleaning of refuse. Coal preparation plant product yield and quality must be evaluated in terms of the amount of capital expended and cost of operation. Therefore, it is advantageous to optimize the plant product based on clean coal selling price and rate of return on investment.

Jan 1, 1976

By J. J. Sense

The Mission Unit of American Smelting and 'Refining Company is located in Pima County, Arizona, approximately twenty miles southwest of the City of Tucson. The Unit consists of an open pit copper mine and concentrator. The concentrate is shipped by rail to Company Smelters at Hayden, Arizona, or El Paso, Texas Mine stripping began at Mission in the fall of 1959, and construction of the 15,000 tons per day concentrator gas started in the spring of 1960, The first ore was treated in mid summer of 1961 and full ore production was reached in August of 1961. At that time over 46,000,000 tons of material had been moved from the pit. Current production (ore and waste) averages over 100,000 tons per day. Total production to date (ore and waste) over 120,000,000 tons.

Jan 1, 1964

By M. Guzman, S. B. Thais, M. F. Obispo, M. R. Arribasplata

One of the greatest environmental issues related to the development of the mining activity is the generation of Acid Mine Drainage (AMD). Many methods have been developed for AMD treatment, being wetlands a good option for heavy metal removal. In this sense, the implementation of artificial wetlands for the treatment of mining effluents would seem to be an environmentally friendly alternative. In this paper, we present the results on the elimination of heavy metals (Cu, Zn, Pb and Fe) using two Peruvian native species such as Schoenoplectus californicus (C.A. Mey.) and Phragmites australis (Cav.) Trin. Ex Steud. The results show that Schoenoplectus californicus preferentially removes copper (82 and 90%), lead (88 and 92%) and iron (28 and 69%), whereas Phragmites australis removes copper (68 and 87%) and zinc (53 and 95%). Likewise, it is observed that the Schoenoplectus californicus mainly retains the ions in its root, copper (89%), zinc (84%) and iron (76%). While the Phragmites australis accumulates iron (62%) and copper (74%) in the steam and root part respectively

Mar 2, 2022

By R. Gorakhki, R. Stafford, A. Jung

Geosynthetic clay liners (GCLs) have been used widely as an alternative for compacted clay liners and covers in mine waste applications. The high swelling of bentonite particles in the GCL creates a uniform barrier layer that results in low permeability of water and mine waste leachate. GCLs must provide sufficient internal and interface shear strength stability, especially if GCLs are used in steep slopes under high normal loads. Peel strength is a common parameter that is typically correlated to internal shear strength properties of GCLs. The relationship between internal shear strength and peel strength of GCL at normal stresses of 287, 575, 862, and 1724 kPa is evaluated in this study. The data in this study was compared with the peel strength-internal shear strength relationships found in literature. The study concludes that the relationship between peel strength and internal shear strength is unique based on manufacturing, needle-punching density and the method with and without heat treatment of the geotextile end fiber bundles.

Feb 1, 2023

By K. L. Hanning

Grinding and classification circuits at Climax Molybdenum Co. are described. Since the installation of a direct digital control computer in 1974, a number of control strategies were developed and evaluated. This paper deals in particular with the practical experience and results obtained in direct digital control of a wet grinding circuit consisting of a ball mill, constant speed sump pump, and hydrocyclones. For this circuit throughput is maximized, while maintaining a desired product size. Product size is inferred from measurement of operating variables.

Jan 1, 1977

By L. Figueroa

Electrochemical methods have potential to treat waters impacted by mining, while simultaneously producing a recoverable metal product to off-set treatment costs. Mining-impacted waters may present challenges with electrochemical treatment due to low concentrations and complex solutions of numerous dissolved metals. This paper presents an evaluation of the potential strengths and limitations of abiotic electrowinning of mining-impacted waters. In particular the impacts of chemical composition on metals removal are evaluated. Results of bench-scale experiments demonstrate the potential to remove metals on the cathode (copper, cadmium, lead), as well as the anode (manganese). Pre-treatment for iron and aluminum may be needed and post-treatment pH adjustment would be necessary. INTRODUCTION Due to continually increasing demand for metals, new technologies and innovative applications of existing technologies are needed to recover metals from mining-impacted waters. Electrochemical methods have long been used for metallurgical processes with solutions containing high concentrations of the target metal. However, electrochemistry also has potential to treat waters with lower metal concentrations, while simultaneously producing a recoverable metal product to offset treatment costs. Electrochemical water treatment may have several benefits over traditional alkaline treatment for acid rock drainage (ARD). Sludge produced from alkaline treatment has high water content that is difficult to dewater, even for treatment plants producing a relatively high-density sludge. For example, the Argo Tunnel Water Treatment Facility (Argo Facility) in Idaho Springs, Colorado uses hydrated lime to produce a high-density sludge with a solids content of 20 to 25 percent and filter cake with solids content from 30 to 35 percent [1]. Furthermore, costs for managing the sludge are significant, approximately $90,000 per year for treating approximately 150 million gallons of water [1]. Although not the case for the Argo Facility, sludge produced from alkaline treatment of ARD has potential to be classified as hazardous. Disposal of sludge also opens up the potential for future liability depending on the sludge’s chemical stability and methods of disposal. In contrast to alkaline treatment, electrochemical treatment produces metals in elemental and other highly-dense forms on the cathode. If metals concentrations and flow rates are sufficiently high, the metals recovered may help offset overall treatment costs. In addition, sludge production would be reduced, if not eliminated altogether, thereby reducing both disposal costs and potential future liabilities as well.

Jan 1, 2019

By H. E. Rudi

The advent of open nit mining permitted the development and processing of minerals never before thought possible. New equipment was needed; new techniques were devised; new methods were called for. This development and acquisition of new techniques, methods and equipment did not, however, stir the souls of our industry and educational leaders sufficiently to a recognition of the problem of people, especially the future development of the people needed in open-pit mining. The people problem has been and will be with us as long as there are two of them. The development of people will be required for the same reason. The problem of developing future personnel for open-pit mining is not what must be developed; that is known to all of us and can be briefly stated ashore and better of everything." As I see it, the real problem lies in determining (1) what personnel are really critical, (2) why are they critical and (3) how can we develop them.

Jan 1, 1965

By J. D. McKay

Flotation columns have been readily accepted for use in most sulfide flotation plants; however, recently columns are being used in many other areas. Recent improvements in design methodologies have overcome many operating problems and led to improvements in metallurgy. In addition, physical improvements in column design have simplified their operation while leading to better control. The Turbo-Air External Bubble Generator has provided a method for bubble size control and variation in air holdup and carrying capacity. These have enabled commercial operations to improve grades and recoveries by optimizing performance.

Jan 1, 1990

By D. Castillo

The effectiveness of a flotation column is due principally to the addition of wash water to the froth phase. The wash water flow rate can be significant, especially so for systems yielding a high weight recovery of fine solids, e.g. zinc sulfide flotation. Therefore, it is critical to recognize and assess the impact of the water addition upon upstream separation stages. This paper examines column flotation circuit configurations using data from a portable 2 t/day pilot plant. The objective is to provide an improved basis for column design, either as a retrofit or as part of a new circuit.

Jan 1, 1990

By E. F. Nelson

The 1970s have witnessed the completion and successful start-up of several new non-ferrous metallurgical operations in the Western Hemisphere which utilize large semi-autogenous mills in the grinding circuits. These facilities' are arranged either as single-stage circuits, or in a two-stage configuration n with ball mills. Another major concentrator, designed with an autogenous mill, ball mill, crusher (ABC circuit), is presently under construction and scheduled for start-up late this year. The large primary mills employed in these circuits have high diameter-to-length ratios and are designed to accept a very coarse feed, i.e., the product of a primary gyratory crusher, or run-of-mine ore. This characteristic obviates the need for a secondary-tertiary crushing plant or, in selected cases, even a primary crusher, which is a basic requirement in feed preparation for conventional grinding mills. This paper discusses three such grinding circuits and, presents operating data for two of them: the Island Copper Mine of Utah Mines, Ltd., near Port Hardy, British-Columbia,- and the Pueblo Viejo Cyanide Leach Plant of Rosario' Dominicana, S.A. on the island of Hispaniola. The design criteria for the Cyprus Bagdad Concentrator under construction' at Bagdad, Arizona, are also included. Data pertinent to these circuits are tabulated in the Summary.

Jan 1, 1977

By M. Canty

An innovative biological treatment system designed to detoxify cyanide and nitrate and immobilize metals from cyanide leach operations is described. A pilot-plant demonstration was conducted to detoxify cyanide and immobilize several metals from a process stream at the McCoy/Cove Mine. Testing was performed under the EPA's Mine Waste Technology and Superfund Innovative Technology Evaluation Demonstration Programs. This technology was successful in detoxifying cyanide and effective in removing metals. The pH was consistently neutralized and nitrates were successfully removed. Results show that biological treatment can offer an innovative, cost-effective alternative for the treatment of mining wastewaters.

Jan 1, 1999

By J. D. Miller

"It is now possible to use 3D X-ray tomography analysis for plant-site characterization of coarse particles at a sampling rate of about 3 kg/min for particles which range in size from 150 mm to 1 mm at a voxel resolution of about 150 microns. This is quite a significant advance in X-ray tomography technology and should be useful for plant-site coarse particle characterization (size, shape, composition, density, texture, grain exposure, mineral liberation) with a response time of minutes after receiving the sample. Applications in the mineral industries are discussed including the coal industry, aggregate industry, metal mining and the processing of industrial minerals. INTRODUCTION Plant-site characterization of coarse particles at coal preparation plants, crushed stone/aggregate plants, and mineral processing plants is needed to improve plant capacity, product quality, and/or process efficiency. Not much on-line coarse particle characterization is done at these plants. Some limited information regarding particle size is obtained on-line from reflected light images using systems such as the OPSA, Split, and WipFrag analyzers. Even laboratory analysis of coarse particles has been difficult because of the large amount of sample required to insure statistical significance of the results. During the past decades laboratory 3D characterization of particles from energy and mineral resources by X-ray tomography has been demonstrated and used to good advantage [1, 2]. 3D X-ray tomographic analysis had its origin in the medical services industry; it is used to provide internal images of the human body and now has also been developed for non-medical applications [3]. Figure 1 shows a schematic diagram for the cone-beam geometry micro-CT system. In our case X-rays from a microfocus X-ray generator are partially attenuated by the sample (a packed bed of particles) that is made to rotate in equal steps in a full circle about a single axis of the particle sample. At each rotational position, the surviving X-ray photons are detected by a planar two-dimensional array (image intensifier) large enough to contain the shadow of the specimen. These two dimensional projection images are collected using conventional video technology. The video signal for each projection is then converted to a two-dimensional digital array by an image processing system. Finally, a three-dimensional image is reconstructed from the collected set of projection images. With the availability of automated high speed X-ray tomography [4] it now seems possible to do plant-site particle characterization at a sampling rate of about 3 kg/min for particles which range in size from 150 mm to 1 mm at a voxel resolution of about 150 microns. This is quite a significant advance in X-ray tomography technology and should be useful for plant-site particle characterization (size, shape, composition, density, texture, grain exposure, mineral liberation) with a response time of minutes after receiving the sample. Applications in the mineral industries are discussed including the coal industry, aggregate industry, metal mining, and the processing of industrial minerals"

Jan 1, 2016

By M. Z. Rashad

The purpose of this paper was to compare the covariance and multiquadric functions in same mining and geological applications. The basic principals of the two techniques are covered briefly. Similarities and dissimilarities of the covariance and multiquadric functions are discussed geometrically, mathematically and practically. A 14 by 16 kilometer square area in Baharia Oasis, Western Desert of Egypt, was selected for a detailed comparative test. The gravity anomalies of forty-eight test stations were computed by using the data of sixty-three control stations. The results indicated that the covariance function is quite better than the multiquadric one. On the other hand, the multiquadric function more simple in computation than the other one, which needs to precalculations such as semivariogram and covariogram. Moreover, multiquadric equations are based on geometrical and physical considerations rather than covariance functions.

Jan 1, 1990

By G. S. Dobby

The Cu-Au flotation cleaning circuit at Freeport Indonesia consists of three stages: two flotation column stages, in series, followed by one stage of mechanical cells. Concentrate from both column stages is combined as final concentrate. The mechanical cell stage has two parallel rows of seven Wemco 500's. The Wemco concentrate is recycled to feed of the second column stage and Wemco tails report to final tailings. This paper examines cleaner circuit performance, focusing on size-by-size performance of the individual stages and the individual mineral groups -copper sulfides, gold and in sol minerals. The recovery mechanisms of insol minerals are examined.

Jan 1, 1995