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By D. Gignac, P. A. Studemeister, H. Koza

Two epiclastic horizons in an Archean volcanic sequence host the gold occurrences on the Dunraine property near Wawa, Ontario, Canada. The Grace horizon of cherty and pelitic tuff strikes north-northwest and dips east. Native gold occurs with arsenopyrite in bedlike and podlike bodies of quartz lenses and stringers set in a pelitic matrix. The Parkhill horizon of lithic graywacke with associated flow-breccia strikes southwest and dips south. Native gold occurs with minor sulfides in similar bodies of quartz erratic within the Parkhill horizon. The auriferous bodies occupy paleotopographic channels and troughs within the two horizons. The former producers are the Parkhill mine with 1689 kg (54,300 oz) Au, Darwin mine with 473 kg (15,200 oz) Au, and Van Sickle mine with 48 kg (1536 oz) Au between 1902 and 1944. The gold occurrences are syndepositional with the host volcanic sediments laid during a pause in explosive volcanism. Fumaroles along steep gullies on the flank of a subaqueous volcanic center precipitated aprons of auriferous silica-sulfide mud. Downslope slumping resulted in exhalative debris flows; gold concentrated in flexures and depressions along stumpage channels. Renewed explosive volcanism covered the auriferous sediments with pyroclastic tuffs, arresting the slumping of in situ fumarolic deposits.

Jan 9, 1985

By Wayne A. McCurdy

I welcome the opportunity to meet with you and discuss the work and program of the Office of Coal Research. Our programs are oriented to serve the conservation objectives of the Johnson Administration and of the Nation by seeking out the most efficient and best uses for coal. We believe that even if only a portion of our program is successful, the coal industry and the Nation will benefit far out of proportion to our expenditures. Operating with a budget of $7,220,000 in Fiscal Year 1966, OCR sponsors contract research which offers potential for achieving benefits to the coal industry in the form of new production and new markets. This directs us into many areas of research activity: in coal combustion, in advancements in mining methods and coal preparation, in new uses for coal, and in associated economic and marketing research.

Jan 1, 1966

By Gordon Kidd

Inflation and burgeoning costs are two among many factors which have generated a new surge of interest in "fringe benefits" (sometimes referred to as "supplementary remuneration" or "supplementary compensation"). Other specialized forms of compensation ("perks", in the vernacular) such as company cars, windowed offices, etc., which also are the subjects of current study, are outside the scope of this paper. For businesses, interest in fringe benefits is based on concern for employees? welfare, compliance with government requirements, and an increasingly burdensome impact on bottom lines. In 1980, according to Fred D. Lindsey in the October 1980 issue of Nation's Business, employee benefits will cost American employers an estimated $420 billion. To paraphrase Winston Churchill, "some fringes!" Indeed, few if any administrators consider employee benefits as fringes. Employee benefits impact other major areas of a company's operations as well. As listed by Beadle (1980), these areas include employee relations, collective bargaining, short-term costs, long-range funding, manpower planning, compliance with legislation, taxation for the company and for the employee, corporate image in the community, competitiveness for staff, communications, administration, claims cost containment, etc., etc.

Jan 1, 1980

By Walter M. Chapman

The National Lead Company operates its MacI tyre Development at Tahawus, New York for the production of ilmenite and. magnetite. The heavy ore of titanium and iron is mined from the open pit mine at an average rate of 7,000 tons per day, and the development waste is removed at an average rate of 10,000 tons per day. The mine working benches are spaced, at 35-foot vertical intervals, and 6 ½ inch blast holes are drilled 39-feet deep with 18-foot burden and spacing by down-the-hole drills. Waste is loaded with a 6 yeard shovel and ore with 2 ½ yard shovels into 22-ton rear dump trucks. A good account of the history of MacIntyre drilling and. blasting was presented to this assembly two years ago, by F. R. Jones. (1) Most of the blasting since the start of the mine in 1941 was done with 90% gelatin dynamite until 1955, when relatively insensitive canned blasting agents were adopted.. In 1956, 9-inch blast holes drilled with down-the-hole drills. In 1956, also, the first experimental trials of prilled ammonium nitrate fertilizer and fuel oil (hereafter called fertilizer) was made following the lead of Cleveland-Cliffs operations in the Hibbing district. Since that trial did not, as some local skeptics predicted, make grass grown on the bluff, but resulted in a well-broken shot, further tests were conducted in dry holes. I Observations of those tests indicated that the fertilizer did its share of the work. If anything, it produced better fragmentation than the normal load di in neighboring wet holes.

Jan 1, 1958

By W. P. Barnett

In 1988, the U.S. Department of Energy's Pittsburgh Energy Technology Center identified three coal cleaning options for achieving flexible environmental control strategies aimed at reducing energy-related SO2 emissions. These are selective agglomeration, advanced froth flotation, and advanced cycloning. Each technology relies on maximum liberation of pyrite and other mineral matter through feed coal comminution to fine and ultrafine sizes. Research projects designed to expeditiously develop each of these technologies to the point of commercial viability were initiated. This paper will present the status of these projects and the application potential of each technology to coal beneficiation.

Jan 1, 1992

By Raphael G. Kazmann

Water occupies a dual role in our industrial society. It is the indispensable raw material, essential to life itself. It is equally an industrial nuisance, interfering with the production of industrial minerals, making construction difficult, flooding valuable land, and generally producing problems because it is in the wrong place at the critical time. The legal position of water as a nuisance, and the counter measures to be taken, have been well established procedures for determining the responsibility for damage caused by water, and the organization of drainage districts and flood control and levee districts have been legally tested many times. Thus there is rather adequate legal doctrine concerning water, the common enemy. But recently efforts have been made to regularize the position of water as a useful, industrial, commodity. Such laws are not new to the West, where the doctrine of appropriation for beneficial use is slowly becoming the water law. Elsewhere the University of Michigan has produced a "model" water law and efforts are being made to induce all of the states to use this law, or a slight variation of it, as the basis for legislation. There are many serious criticisms of the proposed "model"-law, and the writer strongly opposes many of the provisions. But the fact remains that water is, in itself, so useful and essential that laws have been, and will be, passed to insure the orderly development of our water resources and to prevent waste. The, most important aspect of these "water-use" laws is that, wise or unwise, the existing laws and the proposed laws have been "water oriented". "Water oriented" means that it has been tacitly assumed that the beneficial use of water, either surface water or ground water, is the overriding consideration.

Jan 1, 1960

By A. P. Gentsch

Commercially mined calcium carbonate is normally found near the surface in the United States. It is nun& either by open pit or underground methods, depending upon its geologic setting. Processing ranges from simple crushing to the more sophisticated ultrafine processes. Intermediate steps are pulverizing, screening, beneficiation, classification, fine and ultrafine grinding, and surface treating. These processes are performed both dry and/or wet resulting in powdered or slurry end products.

Jan 1, 1986

By Felicia F. Peng

One of the serious environmental problems related with the extraction of coal for carbon and energy resources is that upon preparation of coal a large quantity of fine coal has been discarded and/or lost to tailing impoundments. These problems present hazardous conditions to the local community. Also, the precious heating value of energy resources has been wasted and Left unrecovered in the tailing impoundments. Both RCR and SMRC ACTs recognize and mandate an investigation into slurry impoundment problems, including consideration of potential use of those coal fines in the tailing ponds. Bituminous coal producing district 46 encompasses the northern panhandle of West Virginia. The major producing seam in this district is the Pittsburgh coal, 1-7 meters thick. 75 percent of the coal producted in this district is deep mine. This district produces approximately 3 million tons of coal waste materials annually. One of the coal preparation plants in the district which we have visited has been processing Pittsburgh too. 8 seam coal for the past ten years. The characteristic data of the Pittsburgh raw coal is shown in Table 1. The raw coal produced in this district is characterized by its high heating value, high ash and high sulfur contents. The coal preparation plant flowsheet designed and used to process this Pittsburgh raw coal prior to 1979 is shown in Figure 1. It was a partial coal cleaning plant' with 1 092 mt/hr designed capacity, which consisted mainly of a coarse coal cleaning circuit. The rejected fine particles in the size range of -600µm which consisted of vorsiv underflow and cyclone underflow from clean coal streams and spiral classifier overflow from refuse stream were settled down in a thickener with the aid of anionic flocculant prior to being pumped to the tailing ponds for disposal. Figure 2 shows that the same coal preparation plant in Figure 1 was modified to a semi-complete coal cleaning plant and expanded its designed capacity to 1 820 mt/hr, when market of coal fines becomes feasible in 1979. Tabling in the clean coal circuit and thermal dryer in the dewatering circuit were added to the flow sheet. The purpose is to recover more coal fines, reduce more pyritic sulfur and ash contents in coal and also to reduce solid waste material to be stored into the slurry impoundment, giving them a Longer Life. The rejected fine particles fed to the thickener are clean coal fines from two cyclone overflows and the fine refuse from the rufuse cyclone overflow. The clean coal fines presently lost to the tailing impoundments are in the size range of -150 µm and constitute about 5 percent of the overall plant feed. Total amount of tailing waste material accumulated in a tailing impoundment is estimated at 1.3 million metricton for the past ten years.

Jan 1, 1982

By G. J. Gersbach

The Robe River Iron Ore Project began in 1962 when Cliffs International acquired mining leases in Western Australia's Pilbara Region. Initial reserves were proven and bulk ore samples sent to the U.S.A. for pilot plant testwork. Cliffs Western Australian Mining Company Pty. Limited (30%) manages the project in joint venture with Mitsui Iron Ore Development Pty. Limited (30%), Robe River Limited (35%) and Cape Lambert Iron Associates (5%).

Jan 1, 1983

By Earl Rau

Introduction Will cogeneration be a major power source in the future? The location of electric power generating plants has changed. In 1900, more than 50% of electricity was generated by industrial plants. Since then, industrial plant generation of electricity greatly decreased to 17% in 1950 and to only 3% in 1980. Changing economics in electric power generating costs, though, may allow cogeneration to reverse this trend. Cogeneration has been defined as the simultaneous production of electric (mechanical) and thermal energy from a single energy source. Some applications are considered to be byproduct generation of electricity from industrial, thermal operations. Cogeneration is not new to the mining and minerals industry. Smelters and steel mills have used waste heat to generate electricity. Public Utilities Regulatory Policies Act of 1978 The potential for increased industrial cogeneration of electricity is related to the March 9, 1978 enactment of the Public Utility Regulatory Policies Act (PURPA). The US Supreme Court ruled that PURPA is constitutional. The court upheld requirements that utilities interconnect to cogenerators. It also ruled that 100% of avoided costs be used as the guideline for electricity sales by a qualifying facility (QF) to a utility. The state of New York established a floor price $0.06/kWh for electricity sales from a QF to a utility. It is obvious, then, that a cogenerator must first establish price and then become a qualifying facility in order to sell electricity to a utility. Proposed cogeneration plants The estimated industrial cogeneration potential for the years 1986 to 2000 is 9500 to 25,000 MW. Industries represented in this cogeneration estimate are pulp and paper, petroleum, chemicals, food, textiles, rubber, plastics, steel, lumber and wood, cement, glass, metal fabrication, and industrial parks. A cogeneration plant has been proposed for the Union Carbide chemical plant in Institute, WV. A steam turbine/generator would be installed to replace the pressure-reducing valve in the 2.7 MPa (400 psig) header. Scott Paper Co., Mobile, AL, proposed a cogeneration plant using a coal- and wood-fired boiler and a turbine/generator to produce process steam and electric power. A cogeneration system has been proposed for a large oil refining plant. A pulverized coal boiler would produce high-pressure steam to operate a turbine, generator. The exhaust steam from the turbine will go to the process and an existing turbine. Kansas City, MO's Armour meat-processing plant has proposed a cogeneration plant. This proposal is to use a natural gas or oil-fired, gas-driven turbine and a generator. The waste heat from the gas turbine would go to a heat recovery boiler for use as process heat. Dade County, FL is implementing a central energy system to supply electricity, air conditioning, and domestic hot water for five buildings in downtown Miami. The cogeneration system is to provide flexibility, to optimize fuel use efficiency while serving the variable thermal demands. Generation of electricity from municipal waste is not considered to be a cogeneration process but is covered by PURPA. Special considerations are provided for waste/electric power generation to encourage the development of these systems. ?

Jan 7, 1987

By Harry H. Peek

Artesian pressures of unusual magnitude occur in the deeper aquifer units beneath a considerable part of southeastern North Carolina and extend into South Carolina. The high pressures were first observed in 1968 in wells near Wilmington that were drilled to "basement" rock and which were screened between depths of about 260 to 300 m (meters). The pressure was recognized by Peek and Heath1 as an anomalous geo-pressure and unrelated to recharge conditions in the region. Since 1973, much new information has been obtained on hydro-geologic conditions in the area and a preliminary report on the deep artesian pressures was published in 1975.2 Most of the basic information has been obtained from groundwater research stations constructed by the Groundwater Section of the North Carolina Department of Natural and Economic Resources as a part of Ground-water studies in the Coastal Plain Region. These stations consist of an exploratory well drilled to basement rock with wells completed in each principal aquifer unit to provide data on aquifer characterestics, water levels and water quality.

Jan 1, 1977

By Byron R. Berger

Epithermal Ag-Au deposits form at low to moderate temperatures in near-surface environments. Historically, these deposits have been the source of high-grade ores. Increases in the market prices for gold and silver make lower-grade ores economically viable when available in large tonnages. Both the high-grade and bulk-tonnage ores are a consequence of the same processes, and general models of epithermal systems can be useful in the search for new precious-metal resources. A detailed study of deposits at Round Mountain, Nevada; Balei, Russia; Creede, Colorado; Guanajuato, Mexico; and Chanarcillo, Chile, indicates that the hydrodynamics of the fluid systems as determined by fracture geometries, the permeability, and composition of the host rocks are the key factors in the creation of both high-grade and bulk-tonnage epithermal deposits. End-member models that explain the range of observed deposit characteristics are: (1) the hot-springs deposition model; (2) the stacked-cell convection model (where mineral deposition occurs laterally along the interface of two partially separated fluid reservoirs); and, (3) the closed-cell convection model (where deposition occurs in vertical zones due to the relatively unimpeded vertical flow of hydrothermal fluids). Boiling and fluid mixing appear to be agents of precious-metal deposition with the self-sealing of the hydrothermal system being an important adjunct to boiling. Imaginative application of model concepts in exploration has led and can lead to the discovery of new high-grade and/or bulk-tonnage precious-metal deposits.

Jan 1, 1982

By Khosrow Badiozamani

Operating mines in Wyoming and Montana, which are generally characterized by shallow overburden and thick coal seams, are faced with reclamation problems which are unique to this area. Unlike the eastern or midwestern mines, removal of thick coal seams and lack of sufficient overburden creates overburden deficiencies that require careful evaluation prior to mining to insure compliance with regulatory requirements. Computer models and computer graphics can assist in such evaluation where appropriate alternatives can be selected which satisfies both the regulatory requirements and minimizes cost. This paper presents one such model used in evaluation of backfill requirements for restoration of surface and ground water regimes, restoration of mined-out areas to the approximate original contour, and the blending of the mined-out areas to the surrounding topography.

Jan 1, 1981

By K. C. Vories

Surface mining and reclamation has the potential to at least temporarily increase surface runoff and resultant erosion and gully development. This increase in erosion is due in part to compaction of the soil surface with heavy equipment, creation of large relatively unvegetated watersheds, and elimination of natural dendritic ephemeral drainage patterns. Methods for stabilizing gully channels which may develop prior to establishment of sufficient vegetation to control erosion are analyzed. Utilization of various sizes of riprap for channel lining, the use of riprap check dams, reinforcement of riprap check dams, and the relation- ship of type of control structure to area of watershed and resultant flow velocities are discussed.

Jan 1, 1986

By R. D. Hansen

This paper discusses the influence of frother type and dosage on recovery/selectivity in coal/sulfide mineral flotation as a function of particle size. It is shown that different frother structures do exhibit quite different but consistent performance characteristics depending on the underlying particle size ranges involved as well as the dosage levels of both the frother and collector. The data presented on existing commercial frothers end some new special purpose experimental frothers is used to illustrate some general operator guidelines on proper frother selection and use.

Jan 1, 1985

Mineral Resource Technologies(MRT) and Michigan Technological University (MTU)finalized an agreement that permits MRT to offer an advanced carbon removal technology process for coal fly ash from an ash residue generated by utilities. The agreement encompasses the dominant existing US patents using a wet process for fly ash enhancement. The wet process for coal beneficiation of a fly ash product involves four steps. First, a slurry mixture is formed of a fly ash material and a liquid. Second, gravity is used to separate and collect a first-material fraction of the fly ash, having a density less than the liquid. This is done by skimming off the flotation slurry material.

Jan 1, 1996

By P. M. Soupios

An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regimes of the study area, to determine the geometry of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock fabric fractures and to locate potential zones of electrically conductive contamination. The study area which covers an area of about 0.08 Km2 is a municipal solid waste site (MSW), located 20Km West of Herakleion in the central part of Crete (S. Greece). The landfill is located in a northwest oriented valley with highlands to the northeast and southwest. The combination of geophysical methods and chemical analysis are commonly implemented for characterization and management of land-fills. At the particular site, geophysical methods were focused on studying the electrical insolating properties of the materials, electrical con-ducting properties of fluids (leachates) and electromagnetic properties of the disturbed regolith materials in the burial zones. Three different types of geophysical surveys were performed: 1) 2D electrical tomography (ERT), 2) electro-magnetic measurements using very low frequencies (VLF) and 3) electromagnetic conductivity (EM31). Furthermore, in order to calibrate the geophysical methods dielectric spectrometry measurements are conducted. To evaluate the environmental degradation of the area, soil and liquids samples were collected.

Jan 1, 2005

By I. K. Choi

In a recent paper by Smith and Wen(1) the adsorption of sodium dodecylsulfate and trimethyldodecylammonium chloride on kaolinite was studied. As would be expected considering the general negative character of kaolinite, except perhaps at quite' acid pH values (2,3,4), it was found that trimethyldodecylammonium chloride adsorbed strongly on kaolinite at basic pH values. Furthermore, it was found that sodium dodecylsulfate adsorbed strongly on kaolinite at acid pH values, particularly at initial 1H values below pH 3 (final pH values near pH 4). It is interesting to note that adsorption of the anionic surfactant was strong under conditions where the kaolinite was apparently slightly negatively charged (2). The present paper reports on an extension of the work by Smith and Wen. In this paper the effects of the presence of dodecyl alcohol and sodium hexametaphosphate on adsorption of sodium dodecylsulfate and trimethyldodecylammonium chloride on kaolinite are considered.

Jan 1, 1967

By Ian McFeat-Smith

Despite a present, short-term economic recession, a remarkable enthusiasm exists in Hong Kong for building infrastructure including major tunnel projects. This paper provides details of current and recent bored tunnel works together with an insight into the impressive list of future underground projects planned by the MTRC,KCRC, Highways Department and Drainage Services Department for the next decade. Risks for each of these works including pipejacking, mixed face and rock tunnelling generally in Hong Kong are also identified. From this is evident that the scale and difficulty of such works continues to increase, requiring the use of more sophisticated methods of construction, the need for better methods of assessing and managing risks and for Government to utilize improved, more equitable Conditions of Contract for such major tunnelling projects.

Jan 1, 2001

Membrane technology has been available for over 36 years, but has been used sparingly in the general mining industry. However, recent developments in polymer chemistry, spiral wound element construction, pretreatment equipment and techniques and an expanded understanding of membrane fouling and cleaning techniques have dramatically improved the reliability and robustness of membrane based systems in the mining industry. Harrison Western has expanded the use of this “new” technology to enhance the use of membrane technologies to separate metals from large volume heap leach mining solutions containing copper, zinc, and iron, gold or silver. Moreover, membrane technologies are ideally suited to fractionations that add value to processing fluids from refineries like separating metals from acids or concentrating acids and producing high quality process fluids. Finally, wastewater from Acid Mine Drainage (AMD) or, as in the case of the Newmont Yanacocha Mine in Peru, the treatment of excess barren leach solution created during the rainy season, can be cost effectively processed to meet World Bank Standards for surface discharge. Polymeric membranes, specifically thin-film composites, have been developed that will purify, fractionate or concentrate gold, silver, copper, zinc or nickel. Recent applications have been developed for spiral wound modules that operate across the pH spectrum from 0 to 14. Systems using membranes have been constructed that operate on feed streams from 140° C to 300 centipoise. Opportunities exist to apply membrane technology to concentrate gold, silver, copper, zinc or nickel using thin film composite membranes. Engineered membrane types can operate across the spectrum from low pH (<2) acid applications to high pH > 10 cyanide applications. Incorporating HW EMS™ membrane technologies into current mining operations could allow one to increase production because the membrane technology would be used to pre-concentrate heap leach solutions, and therefore, increase utilization of existing extraction and refinery capabilities.

Jan 1, 2007