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By Walter Estrada, Fernando Valencia, Jaime Luyo

La gasificación por plasma es un proceso térmico a alta temperatura en el que los desechos se descomponen en elementos fundamentales y compuestos simples en un entorno anaeróbico. El sistema presentado en este artículo actúa como un digestor al transformar las moléculas de carbono y otras sustancias en compuestos menos contaminantes. Se utilizó una mezcla de cianuro disuelto en agua como muestra de ensayo —procedente de aguas de una mina—, que se sometió al componente radiante de plasma, y se estudió la energía generada actuando sobre la purificación y transformación de las muestras.

Sep 30, 2019

By B. W. Hester

Report of discussion at January, 1971, general meeting (Chairman: M. J. Cahalan, President) of the paper published in Transactions/Section B (Applied Earth Science), vol. 79, May, 1970, pp. B60-B67, and contributed remarks. Comments were made by Taylor J.T.M., James C.H., Lethbridge R.F. and Heath K.C.G.

Dec 1, 1971

By Paul H. Johnson

Heap leaching is a simple means of recovering copper from oxide and oxide-sulfide ores. Although this method requires relatively low capital investment, it suffers from low copper recoveries and relatively high acid consumption. The objectives of this study were (1) to determine what factors influence these shortcomings, and (2) to establish a basis of correlation. between laboratory and field testing. The principal methods of leaching copper ores at the present time are heap, dump, in-place, and vat. A number of references are presented in the bibliography on the theoretical and practical aspects of these methods. In the heap-leaching method, crushed or uncrushed oxidized copper ore is placed on a prepared drainage pad. Acid leach solutions are dis¬tributed over the top of the heap, caused to percolate downward through the ore bed by gravity, and are drained from its base. The leach duration is generally a matter of a few months. Dump leaching is used to recover copper from very low-grade oxide-sulfide pit-waste materials. Here again, leach solutions are, percolated downward through a heap. However, in this method, little or no acid is added to the leach liquors, prepared drainage pads are not used and the leaching cycle is generally measured in terms of several years. Leaching agents are usually autogenously generated by the breakdown of sulfide minerals within the dump.

Jan 1, 1970

By Paul C. Merritt

Samuel Hopkins, an 18th century inventor from Philadelphia, has been little noted nor long remembered by History, but it was he who on July 31, 1790, obtained what no other man can ever achieve -the first patent issued by the Government of the United States. Signed by President George Washington, the patent guaranteed to Hopkins the protection of the American Government for his "improvement, not known or used before, . . . in the making of Potash . . . by a new Apparatus and Process." The patent itself is no longer important, but it serves as a milestone in the development of an industry that is now rapidly moving to fulfill its role as a mineral to feed the world. Potash ranks as one of the oldest products of Man, having been used as a condiment by the habitants of Gaul a thousand years before Athens achieved its Golden Age of culture. By Hopkins' time, the uses of potash had changed considerably, going primarily into glass-making, tanning, soap, and explosives, yet the same sources and techniques of manufacturing potash used during the earlier 2000 years-that is, leaching of plant ashes in iron pots with water, followed by water evaporation and crystallization of the potassium salts-were still being used.

Jan 10, 1966

By J. C. Kingston

Introduction The sliding-form method of erecting concrete structures was first devised and used in the early part of this century by the Sante Fe Railroad Company for the erection of a grain elevator at Santa Fe, New Mexico. A somewhat related principle has been employed for a number of years in shaft lining work and, to our knowledge, was perfected in Butte, Montana, but until the building of the concrete headframe at the Jeffrey mine of the Canadian Johns-Manville Company, Ltd., at Asbestos, Que., the method, as applied to surface structures, was quite foreign to the mining industry in Canada. The current shortage and cost of structural steel shapes has no doubt contributed more than any other single factor to the investigations that have led to the use of reinforced concrete as a headframe building material. Mining men in western Quebec and northern Ontario have shown a great deal of interest in the design and construction of the headframe at the East Sullivan mine in Bourlamaque township, Que., and we have had many queries regarding the methods used and, in particular, for an explanation of the sliding-form principle. This article is written in an attempt to set forth the conditions which were to be met; to explain the construction methods used, and to discuss the economy of concrete headframes as compared with the conventional steel structures with which the mining fraternity is familiar.

Jan 1, 1949

By P. M. Ambrose

This report describes an accident, which took place in the Chemical Corrosion Laboratory at the College Park, Md., Station of the Federal Bureau of Mines. The accident occurred while Walter L. Acherman, chemist, was performing a routine manipulation during a corrosion experiment involving commercially pure titanium and red-fuming nitric acid. There was a sudden and very violent reaction, and a large quantity of acid was thrown in the face and over the body of Acherman, causing serious injury. L. B. Golden, chief of the Chemical Corrosion Section, was exposed to nitric acid fumes during the ensuing rescue and first-aid operations and died on January 25, 1954. According to the medical report, the direct cause of Mr. Golden's death was pulmonary edema and confluent bronchopneumonia; the contributary cause, was inhalation of fumes from red fuming nitric acid. The following employees of the College Park Station contributed to this report by supplying information on the accident and assisted in the rescue operation: L. B. Golden, chief, Chemical Corrosion Section; T. E. Green, chemist; Robert Warf field, chemist; L. A. DeVivo, laboratory mechanic; D. W. Chalkley, laboratory mechanic; E. H. Neagle, laboratory welder; and R. L. Heath, laboratory general mechanic.

Jan 1, 1955

By Larry M. Southwick

Considerable process and equipment development and analysis were conducted during design of Freeport Sulfur's laterite nickel facilities in the late 1950's. These covered ore concentration at Moa Bay, Cuba, and concentrate refining at Port Nickel, Louisiana. Both facilities utilized acid pressure leaching and product refining steps that were similar to those later used elsewhere in the laterite processing industry. Unfortunately, developments in Cuba removed the Moa Bay facilities from Freeport control. This deprived the project of a start-up that would have allowed thorough resolution of difficulties and a quicker attainment of production capacity. This meant lost opportunity to positively prove and complete the technology when optimum resources and staff were available. This paper reviews the original rationale of how design was developed via laboratory, bench scale and pilot studies by Freeport Sulfur. Some later operating problems will also be discussed. This case is unusual, but the lessons learned may be instructive in the application of difficult and complicated technologies, as well as the need to understand and retain access to the original development and design activities Keywords: Moa Bay, Freeport Sulfur, Port Nickel, acid pressure leaching, pilot plant, pachuca, Chemical Construction, pressure letdown, cobalt, titanium

Jan 1, 2004

By Charles D. Litton

This U.S. Bureau of Mines report details the results of a series of large-scale experiments where small coal fires were used to ignite the conveyor belt at air velocities ranging from 0.76 to 6.1 m/s. In the tests, electrical strip heaters imbedded within a pile of coal were used to heat the coal to a point of flaming ignition. The flaming coal subsequently ignited the conveyor belt located approximately 5 to 10 cm above the coal pile. During the tests, temperature, CO, and smoke levels were continuously measured in order to determine both alarm time and level as the fire intensity progressed through the stages of smoldering coal, flaming coal, and flaming coal plus flaming belt. Analysis of the data leads to certain conditions of air velocity and sensor alarm levels that are required for early detection of conveyor belt entry fires. Two nomographs are presented, which define sensor alarm levels and sensor spacings as a function of belt entry cross-sectional area and belt entry air velocity.

Jan 1, 2010

By Brij M. Moudgil

Florida produced more than eighty percent of domestic phosphate during 1974. This amounted to more than thirty-five million short tons. Ninety percent of this production was used in the production of fertilizers. Other uses of phosphate include food preservatives, fabric dyes, optical glass, photographic films, soaps, plastics, pharmaceuticals and animal feed ingredients. Marketable phosphate rock projections for the nest decade forecast a very healthy growth for the Florida phosphate industry. Associated with the expansion, however, are the corresponding problems of water conservation, air and water pollution and land reclamation. Recognizing mining as an interim land use, the industry is presently engaged in a very active reclamation program. The proximity of the central Florida deposits to rapidly developing urban areas makes it important to undertake successful and well planned reclamation programs. Water use and conservation is of vitil importance to the industry. Water withdrawal from existing aquifers and discharges into drainage systems are closely regulated by state agencies. Water is stored and recycled to maximize usage. In some instances water is even returned to major aquifers through a series of recharge or connector wells. The phosphate industry has spent over 200 million dollars in the past decade for research, development and implementation of pollution abatement and water conservation systems.1 The following discussion outlines various phases of phosphate mining in central Florida today, with emphasis on research in waste disposal techniques and progressive land reclamation programs.

Jan 1, 1975

By Robert L. Clayton, Arthur Baker

Two massive sulfide zinc-copper ore bodies are in quartz-sericite schist (probably formed by regional metamorphism of sediments) and andesite of the Precambrian Yavapai Series, on opposite sides of a large rhyolite mass. The Copper Queen ore body is conformable with bedding of its schist host rock, but the Old Dick ore body probably crosscuts the strata. A lens of low-grade mineralization in chlorite schist, associated with the Old Dick ore body, crosscuts through 150 feet of strata. The ore bodies are almost entirely enclosed by premineral faults with less than 150 feet of displacement. The minerals of the ores are pyrite, sphalerite, and chalcopyrite, with minor arsenopyrite and galena and small amounts of intimately associated chlorite, sericite, and calcite. Old Dick sphalerite-chalcopyrite intergrowths have mutual boundaries, and sphalerite grains contain abundant exsolved chalcopyrite. Copper Queen sphalerite-chalcopyrite intergrowths have extremely ragged boundaries, the sphalerite contains no exsolved chalcopyrite, and the ore overall has a schistose texture. The pre-mineral fault on the hanging wall of the Copper Queen ore body has had 100 feet of post-mineral displacement. Wall rocks of the Old Dick ore body locally have been sericitized. Andesite and quartz-sericite schists for at least several hundred feet around both ore bodies have been chloritized erratically and contain traces of copper.

Jan 1, 1968

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Morgana Rosset, Bárbara da Rocha Pereira

High-purity alumina finds application in various electronic industry sectors, with approximately 100 million tons of this compound being produced worldwide. Alumina is acquired through the mining process of bauxite, a rock composed of a mixture of minerals such as gibbsite, kaolinite, hematite, and either anatase or rutile. In 2020, both bauxite and alumina were included in the list of critical raw materials. Due to the demand for high-purity alumina production, the development of a methodology to remove impurities present in the leach liquor from bauxite processing by solvent extraction (SX) followed by precipitation has been widely studied. This work aims to obtain high-purity alumina from bauxite by a solvent extraction process followed by a precipitation step from the sulfur leach liquor obtained by the thorough dissolution of Al and Fe from bauxite. Different parameters were evaluated in the SX step, such as extractant type, pH, temperature, and volume-to-volume ratio. The results indicated that using Alamine 336 as an extractant at pH 0 and room temperature led to an extraction of 90% of Fe and 15% of Al. Aluminum sulfate was completely precipitated as aluminum hydroxide and 55% of Fe using NH4OH. After the calcination procedure, obtaining a 99.9% pure alumina was possible without generating a red mud-similar residue.

Dec 28, 2023

By Lei Zhang, Zhibo Ma, Pingye Guo

The mechanical behavior of hard roofs often leads to significant deformation and strong mine seismicity in gob-side entry retaining (GER) of the longwall mining, affecting the mining safety and efficiency of coal mines. Field investigations indicate that the failure process of the retained entry by hard roofs can be divided into three stages. In this paper, theoretical analysis and numerical simulations are first used to evaluate the damage process of the retained entry under the hard roof. The results show that the instability of the retained entry in the conventional GER method results from the combined static-dynamic loads (in stage II and stage III) from the hard roof. Then, an innovative method, through fracturing roofs to maintain entry (FRME), based on GER with the hard roof is introduced to solve this problem. In this method, the roof of the mining area is pre-fractured, and when the coal seam is mined, the direct hard roof will collapse along the fractured surface due to its deadweight and mining pressure. The hard roof control effect on the static and dynamic loads, taking into account the innovative method, is verified with simulations and theoretical analyses. The results are compared with those of the conventional GER method. Furthermore, based on the numerical simulation study of dynamic responses, it is found that compared to the GER method, the dynamic response of the retained entry using the innovative method is more moderate and more conducive to the stability of the entry. Field application also validated the effectiveness of the innovative method to control the mechanical behavior of the “massive sudden collapse” of the hard roof.

Aug 14, 2023

By P. B. Marchant

Bioleach testing and piloting was conducted on refractory gold sulphide concentrate from Austin Gold Venture in Nevada during 1988. The objective of the test programme was to determine the technical and commercial viability of bioleaching as a concentrate pretreatment step prior to gold extraction by cyanidation as an alternative to shipping concentrate to the smelter. Baseline CIL cyanidation typically resulted in < 20% gold extraction from the Austin concentrate. Bioleaching enhanced gold extraction up to 95% using conventional CIL techniques. This paper summarizes the bioleach test programme and results, including pilot plant studies onsite, and describes aspects of the commercial design for a possible retrofit of the Austin flotation tailings leach circuit to accommodate 20 tpd and 40 tpd capacity concentrate bioleach facilities.

Jan 1, 1989

By Kimberly Morrison

Strategically located within the Uravan Mineral Belt District of western Colorado, the Piñon Ridge Project is the first new uranium mill being proposed for construction in the United States in over 25 years. In 1992, dramatic changes to the US regulatory environment for uranium ore processing occurred making regulatory compliance an increased challenge for a new facility. Proposed as a 6.3 million tonne uranium milling operation, the mill will receive ore from a number of mines in the region. The project includes design and permitting of a uranium/vanadium processing facility, tailings cells, evaporation ponds, and ore stockpile pads. The focus of this paper is to provide an overview of the US regulations and how these regulations were applied to design of the mill facilities, as well as provide a status update on the project as the mill license application was submitted to the Colorado Department of Public Health and Environment (CDPHE) in November 2009.

Aug 1, 2010

By D. Fredlund

The decommissioning of uranium tailings facilities often requires the design of a suitable cover system. In northern climatic environments there is a portion each year that can be considered to be ?inactive? while the remainder of the year can be considered to be ?active?. There are numerous engineering design assumptions required when analyzing both the ?active? and the ?inactive? portions of the year. Cover systems are subjected to complex boundary conditions and nonlinear unsaturated soil properties. The proposed paper describes the steps necessary for the preparation and the analysis of a multi-year climatic database for the design of a cover system in northern environments. The paper also explains how climate can be classified and how observed variations from one year to the next can be taken into consideration in cover design. The results of climatic records at two different sites are used to illustrate conditions that need to be taken into consideration when designing soil cover systems.

Aug 1, 2010

By Charles U. Keranen

The Tilden Mine is an iron ore mining, processing and pelletizing facility located on the Marquette Iron Range in Michigan&apos;s Upper Peninsula. It has a designed capacity to produce 8 million long tons of pellets annually from 21 million long tons of crude. It is a partnership owned by The Cleveland-Cliffs Iron Company, Algoma Steel Corporation, LTV Steel Corporation, the Steel Company of Canada, Wheeling Pitts- burgh Steel Corporation and the Sharon Steel Corporation. Cleveland- Cliffs manages and operates the Tilden. The crude ore averages 35% iron and is primarily non-magnetic iron oxide and silica. The major ore mineral is martite. Hematite, earthy hematite, goethite and magnetite are also present. The principal gangue mineral is chert. The ore grains are mostly in the 10 to 25 micron size range which necessitates very fine grinding for liberation. The concentrating process is the most complex one used in the iron ore industry. The unique technology for Tilden was developed in the mid and late 60&apos;s. The design and construction occurred in the early 70&apos;s and operation of the first phase which was of 4 MLTPY capacity began in October. 1974. Expansion of the facility to the current 8 MLTPY capacity was completed in 1979. Chemicals are the key to the beneficiation process at the Tilden Mine. The flowsheet utilizes selective flocculation - desliming, cationic silica flotation and concentrate dewatering by thickening and filtering. Nine different process chemcals are used. The control of the reagent feed systems is highly auto- mated. The entire concentrator is operated from a central control room. The concentrator flow diagram is presented in figure 1. The plant consists of 12 primary autogenous grinding lines, a common crushing circuit to handle an intermediate product within the primary grinding section, 24 pebble mill lines with cyclones and deslime thickeners, 12 flotation lines, 4 concentrate thickeners and slurry tanks, 8 lines of filters with six machines per line, and 2 tailings thickeners. A pumping system was installed in 1980 to permit the direct return of tailings thickener overflow water back to the reuse water pumphouse.

Jan 1, 1986

By R. P. Rothwell

THE milling of silver ores has arrived at a great degree of perfection in the mining districts of our Western States and Territories, and I have thought the record of the practical results obtained at the present time, in a few of the principal districts, would prove of value and interest to many of our members, both at home and abroad. An American silver mill is composed, in descending order from where the ore is dumped, of: 1st. A rock-breaker, usually of the Blake or Alden pattern ; 2d. The battery of stamps, the number of which varies from 5 to 120, generally in batteries of 5 or 10 heads, so arranged that a single battery may stand while the others are running; 3d. The tanks where the crushed ore settles (if it is a wet stamping-mill), or of a drying-floor if the crushing is done dry; 4th. Amalgamating pans ; 5th. Settling pans ; 6th. Agitators or pans in which mercury escaping in the tailings is caught; 7th. Blanket sluices, over which the tailings run, and where mercury and unamalgamated sulphides are saved. A reference to the engravings (see plate), which show one of the latest forms of an 80-stamp silver-mill run by a turbine water-wheel, will show clearly the arrangement of the several parts. THE ONTARIO, UTAH, SILVER MILL. One of the best examples of a silver-mill, and at the same time one of the most successful concerns in the West, is the mill of the Ontario Silver Mining Company, near Salt Lake, in Utah. This mill treats the ore from the Ontario mine, ore which at present is very base, being composed of zinc, lead, and silver sulphides and silver chloride in a quartz gangue. This ore has become baser as the mine attained greater depth, though the vein holds its own, or rather increases, both in thickness and richness. The mill is man¬aged in a skilful and economical manner, though the necessity for * Read at the Montreal meeting, September, 1879.

Jan 1, 1880

By H. Rush Spedden, Arvid Thunaes

Pilot plant test work in 1942 and 1943 showed that by a combination of deslim-ing, fine-size classification, and Sullivan deck concentration it is possible to recover heavy minerals such as cassiterite at least as fine as 10 microns in size. This appreciable improvement in gravity concentration practice has been substantiated by several full-sized plants. IN the past, mills treating ores of tin and tungsten by gravity concentration have recovered very little mineral finer than 325 mesh, although some form of slime concentration has been generally attempted by the use of buddies or round tables. This paper describes a series of pilot plant tests made in 1942 and 1943 in which the use of the Sullivan deck was investigated for the recovery of an appreciable amount of the fine values formerly lost. The investigation was initiated by the U. S. Government in an effort to increase the wartime production of tin. Bolivian milling practice at that time included jigging of the coarse sizes, tabling of the intermediate sizes on conventional shaking tables, and the use of buddies or round tables on the finest sizes. Flotation of the pyrite was employed at different stages of the treatment, depending upon the quantity present and the preference of the operator. Usually good recoveries and the bulk of the production were made in the jigging and tabling operations provided that these sections were not overloaded. Buddies and round tables were used for a small additional recovery if it could be shown that they could pay for their high cost of operation. Extensive test work established that by a combination of desliming, classification, and Sullivan deck treatment, cassiterite as fine as 10 microns (1500 mesh) could be recovered when proper conditions were maintained. This test work has been verified by several full-scale installations. The method is generally applicable to the preconcentra-tion of large tonnages of low-grade ores or tailings for the recovery of a small amount of a valuable heavy mineral. The Sullivan deck (or now the Denver Buckman tilting concentrator), which is the essential part of the method, was devised originally for the recovery of tin from tailings of the Sullivan concentrator, Kimberly, B. C. Since the material treated contained only 0.05 pct Sn, it was impractical to attempt to recover cassiterite finer than 500 mesh.*

Jan 1, 1951

By H. Rush Spedden, Arvid Thunaes

Pilot plant test work in 1942 and 1943 showed that by a combination of deslim-ing, fine-size classification, and Sullivan deck concentration it is possible to recover heavy minerals such as cassiterite at least as fine as 10 microns in size. This appreciable improvement in gravity concentration practice has been substantiated by several full-sized plants. IN the past, mills treating ores of tin and tungsten by gravity concentration have recovered very little mineral finer than 325 mesh, although some form of slime concentration has been generally attempted by the use of buddies or round tables. This paper describes a series of pilot plant tests made in 1942 and 1943 in which the use of the Sullivan deck was investigated for the recovery of an appreciable amount of the fine values formerly lost. The investigation was initiated by the U. S. Government in an effort to increase the wartime production of tin. Bolivian milling practice at that time included jigging of the coarse sizes, tabling of the intermediate sizes on conventional shaking tables, and the use of buddies or round tables on the finest sizes. Flotation of the pyrite was employed at different stages of the treatment, depending upon the quantity present and the preference of the operator. Usually good recoveries and the bulk of the production were made in the jigging and tabling operations provided that these sections were not overloaded. Buddies and round tables were used for a small additional recovery if it could be shown that they could pay for their high cost of operation. Extensive test work established that by a combination of desliming, classification, and Sullivan deck treatment, cassiterite as fine as 10 microns (1500 mesh) could be recovered when proper conditions were maintained. This test work has been verified by several full-scale installations. The method is generally applicable to the preconcentra-tion of large tonnages of low-grade ores or tailings for the recovery of a small amount of a valuable heavy mineral. The Sullivan deck (or now the Denver Buckman tilting concentrator), which is the essential part of the method, was devised originally for the recovery of tin from tailings of the Sullivan concentrator, Kimberly, B. C. Since the material treated contained only 0.05 pct Sn, it was impractical to attempt to recover cassiterite finer than 500 mesh.*

Jan 1, 1951

By K. V. Lindell

THE 70-mile serpentine belt of eastern Quebec, producing 70 pct of the world&apos;s chrysotile, has 11 operating mines, two of which are underground, eight are open-pit, and one is both open-pit and underground. The combined operation, the Jeffrey mine, of the Canadian Johns-Manville Co., Ltd. is the largest producer in the group. Haulage All four of the separate operations falling under transportation at the Johns-Manville Jeffery Mine at Asbestos, P. Q., is handled by the company owned Asbestos and Danville Railway. A variety of equipment is operated over the 25 miles standard gage railway. Included in the scope of transportation are: 1-Hauling mill rock to the mill. 2-Hauling stripping and waste rock to the waste dump. 3-Hauling mill tailings to the tailings dump. 4-Hauling supplies from, and finished products to Danville. Main line tracks are permanent, but those within the pit and on the dumps have to be relocated constantly to follow the mining face and dump edges. Tracks within rock areas in the mine are laid on steel ties and can be moved by a bulldozer. Standard mechanical track shifters move tracks in dirt areas in the mine and on the dumps. Train-movements, both within the mine and over the out-lying tracks are controlled by a dispatcher located at the southwest rim of the pit. Steam locomotives haul all stripping, waste rock, and ore from the mine to the gathering yard at the northwest rim of the pit. Normally, two trains per operating shovel are used, with adjustment for optimum loading. In the event of shovel loading on the bottom level or in good stripping, service may be increased to three or four trains per shovel. From the gathering yard a 100 ton diesel-electric locomotive hauls the mill rock to the mill slips, a distance of about three miles. Electric or steam locomotives haul the waste rock and stripping to the waste dump located about two and one-half miles from the mine. Stripping cars are sprayed with a chloride solution and "gravelled" to prevent wet stripping from freezing in the cars during the cold months. Cars pass under a shaking screen which distributes an even

Jan 1, 1952