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By Charles LeMoyne

The Cable belt Company has been building single flight conveyors for a number of years. The simple design concepts of this type conveyor, introduced over thirty years ago, when distances of one to two miles were considered major advances in technology, remain relatively unchanged. Conveyors that are 6 to 20 miles (9.0 to 32 kilometers) long are being built and are presently in operation through- out the free world. The Cable Belt conveyor is not conventional in its construction. Cable welt differs from conventional troughed idler conveyors in that the driving medium and carrying medium are separated. Motion is provided by two endless steel cables running the length of the conveyor. The cables are driven by a single drive unit incorporating a differential gear which insures identical cable linear speeds and equal tension in both cables at all times. The belting is located and supported by "V" shaped shoeforms moulded to the belt which form a wedging action. The friction between the belting and rope is sufficient to prevent slippage (See figure 01).

Jan 1, 1983

By E. H. Cho

An acid mine drainage sludge sample containing 3.6% Mn, 0.18% Ni, 0.15% Co and 0.39% Zn was obtained from the central part of West Virginia and leached with sulfuric acid at pH 3 and at room temperature. Air was bubbled through the leach solution to precipitate the iron content from the solution at pH 4.5. The leach solution contained 258ppm Zn, 105ppm Ni, 90ppm Co and 2050ppm Mn. Three distinctive solvent extraction studies were performed to selectively extract these metal ions in a sequential operation with DEHPA, Cyanex 272, and then Lix 84. The AIO ratio was 1 and the extractants were diluted 10 times with kerosene. A study of solvent extraction with DEHPA showed that Zn could be extracted without Ni or Co up to pH 2.75. A pH of 2.75 is considered to be the optimum pH to maximize the selective separation of Zn from Mn. The separation factor of Co over manganese suggests that the two metal ions be extracted together by Cyanex 272. The separation factor of Co over Ni indicates that these two metal ions can be separated most effectively around pH 5.3. Also, Ni can be effectively extracted by Lix 84 above pH 5.5.

Jan 1, 1993

By H. K. Lin, J. L. Oleson

The purpose of this study is to develop a mathematical model to describe the oxidation of cyanide with SO2as proposed in the Inco process. This research employed a direct method for measuring the change in cyanide concentration with respect to time as effected by varying concentrations of SO2, copper and pH. Developing this model may be applicable in determining optimum conditions in a process well known and used in the mining industry. It was determined that the reaction is first-order with respect to cyanide, SO2and [Cu+2].The reaction order is 0.15, or zeroth order with respect to [H+] at pH range from 8.0 to 9.5.The activation energy, Ea, is 21.6 kJ/mol. The overall rate equation, as determined through this study is: [ ]

Jan 1, 2004

By V. M. Torres

Arapiraca ore deposit has a mixed chalcopyritelbornite mineralogy, with a copper head grade of 0.7%. The reserve size does no allow profitable exploration by grinding/flotation. The technical feasibility of exploring the reserve by heap leaching was studied. Preliminary agitation tests indicated 85% copper recovery. To simulate heap leaching, column tests were performed. The tests included different ore types and acid addition levels. Operating at pH range 1.6-1.8, 67% copper extraction was achieved. Also, it was found an empirical correlation between the operation pH range, copper extraction and acid consumption.

Jan 1, 1996

By D. D. Murphy

The Bureau of Mines has studied the mechanism of shear-flocculation of silica with stearic acid. At pH 6 and 12, shear-flocculation of silica was not observed with up to 10-4M (5 lb/st) stearic acid. However, in the presence of 0.1 M NaCl at pH 6, shear-flocculation was observed at stearic acid concentrations 10-4 M (5 lb/st). Adsorption of stearic acid on silica was studied using stearic acids spin-labelled with a doxyl group. The presence of the spin-labelling group did not greatly affect the shear-flocculation properties of stearic acid. Adsorption of labelled stearic acid on silica was measured as a function of surfactant concentration with electron paramagnetic resonance (EPR) spectroscopy and gas chromatography (GC). The GC results indicate the stearic acid was predominately adsorbed on the surface at concentrations above 10-4 M. From the EPR spectra, the formation of aggregates of stearic acid was apparent at concentrations of approximately 10-414 (5 lb/st). The results are discussed in terms of a possible mechanism for shear-flocculation.

Jan 1, 1993

By E. G. Cauda

Diesel engines are a major source of underground miners? exposure to nitrogen dioxide. In an effort to reduce the exposure of underground miners to regulated and unregulated diesel emissions, primarily particulate matter, mining companies in the U.S. are retrofitting existing and introducing new engines with various exhaust aftertreatment technologies. Different aftertreatment devices, or changing the operating temperature of a selected device, can have unexpected effects on the concentration of nitrogen dioxide emitted by a diesel-powered piece of equipment. This paper provides an overview of the effects different exhaust aftertreatment technologies available to the mining industry have on no2 emissions.

Jan 1, 2010

By S. Noll

Ventilation is an essential part of any underground mining operation. It provides fresh air for workers and machinery, keeps up an adequate mine climate and dilutes and dissipates noxious gases. Possible changes in the economic environment for mining in the future, e.g. increasing energy costs, will necessitate optimization of distribution of airflow within most mines. This paper discusses the scientific set-up for measurements as well as the behavior and influence of parameters of ventilation according to airflow distribution under consideration of technically possible set-ups of mine fans. This study was done in an underground mine with a flat seam room and pillar mining method.

Feb 27, 2013

By E. H. Cho, P. K. Dai

An acid mine drainage sludge sample, containing 3.6% Mn, 0.18% Ni, 0.15% Co and 0.39% Zn, was obtained from central West Virginia. The sample was leached at room temperature with a pH 3 sulfuric acid solution. Air was then bubbled through the leach solution at pH 4.5 to precipitate the iron. The leach solution contained 258 ppm Zn, 105 ppm Ni, 90 ppm Co and 2050 ppm Mn. Three solvent extraction studies were performed to selectively extract these metal ions in a sequential operation with DEHPA. Cyanex 272 and Lix 84. The A/O ratio was one, and the extractants were diluted ten times with kerosene. A study of solvent extraction with DEHPA showed that Zn could be extracted without Ni or Co up to a pH of 2.75. A pH of 2.75 is considered to be the optimum pH to maximize the selective separation of Zn from Mn. The separation factor of Co over manganese suggests that the two metal ions should be extracted together by Cyanex 272. The separation factor of Co over Ni indicates that these two metal ions can be separated most effectively around pH 5.3. Also, Ni can be effectively extracted by Lix 84 above pH 5.5.

Jan 1, 1995

By F. Alsobrook

Coleman Quartz Inc. has a long history as the sole U.S. producer of lascas for the cultured quartz growing industry based on its unique deposits in Arkansas. Since 1989 the company has also been producing metallurgical grade silica for the ferrosilicon industry from a deposit of unusually pure Arkansas novaculite. This paper chronicles Coleman's trans-formation of an abandoned railroad ballast quarry into a generator of $1.5 million in annual sales to a nontraditional novaculite market. Potential additional applications for this high quality silica rock will also be mentioned.

Jan 1, 1992

By John Newby, Ulf Gwildis, Ken Massé, Guillaume Roux

How to connect an effluent conveyance tunnel to riser shaft and diffuser arms of an outfall system is dictated by the ground conditions, which ideally include rock or soil strata of low permeability. Where such favorable conditions are beyond reach, both the complexity of designing and the risk of constructing this crucial system connection increase disproportionally. This paper describes the considerations that went into the approach of connecting a 5-m-diameter TBM drive with the in-river riser shaft of the Annacis Island WWTP New Outfall System in the highly permeable Fraser River sands at hydrostatic pressures exceeding 3 bar.

Jun 23, 2024

By P. R. Taylor

The ability to treat refractory gold concentrates that contain appreciable amounts of sulfur and arsenic, in an economic and environmentally safe manner is important to the gold mining industry. Processing alternatives include: autoclave oxidation, bacterial oxidation and roasting. Roasting may be the cheapest of all the alternatives if inexpensive methods can be found to contain the arsenic and sulfur. The research program, being reported here, has been evaluating the ability to use hydrated lime in the roaster to capture both the arsenic and the sulfur. Lime roasting is not a new idea, it was proposed for copper ores by Bartlett in the early 1970's (Bartlett and Haung 1973) and for cobaltite concentrates by Taylor in the early 1980's (Taylor et al., 1981). In addition, ores have been roasted that contained limestone and it was shown that partial capture of the sulfur was possible. Lime -sulfur containment has been proposed for the coal fired electricity industry, as well.

Jan 1, 1992

By A. Cecala, J. Noll, J. Hummer

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent.

Jan 1, 2015

By P. L. Sibrell

Three different refractory carbonaceous gold ores from the Carlin operation in northeastern Nevada were investigated to characterize the effect of passivation treatments on the nature of the carbonaceous material. The carbonaceous material was chemically isolated from the ores and passivated residues, and examined by FTIR spectroscopy, elemental analysis, and gold adsorption capacity. The main component of the carbonaceous material in these ores was found to be a naturally occurring activated carbon-type compound. Hydro-carbons were detected on rare occasions, but no evidence was seen for humic acids. Ore samples were passivated by autoclaving, or by treatment with sodium hypochlorite or gaseous Chlorine. In some of the passivation tests, a new peak was observed in the IR spectra of the isolated carbonaceous material, that was due to carbonyl functionalities. However, all of the passivation treatments tested decreased preg robbing significantly. This suggested that the appearance of the carbonyl peak was due to the severity of the conditions during passivation, rather than the method used.

Jan 1, 1990

By Nawal Kishore, Nilesh Pratap Singh, Amit Kumar Verma, Vikram Seervi

In India, despite its natural abundance, demand for coal exceeds its countrywide supply due to failure to achieve high production targets, especially in opencast mines, which are responsible for 94.98 percent of total raw coal production in the country. Employment of technological solutions, such as surface miners, is key to achieving higher coal production and productivity in an environmentally friendly manner, especially in populated areas adjacent to the mining zone. This technology eliminates blast hole drilling, blasting and primary crushing units, thus reducing related environmental hazards like ground vibration and fly rocks.

May 1, 2023

By R. McCulloch

Exploration activity in metallic minerals continued to decline in Montana in 1992 as companies either reduced budgets or left the state. The number of active projects dropped another 50% from 1991. Expenditures were 3% to 6% of 1989's 28.6 million. Many of the major mining companies closed offices in Montana. Although depressed commodity prices have hurried the exodus, continuous changes in environmental regulations, as well as the Mining Law of 1872, without regard to economic effect have had the most serious impact. Many companies indicate that Third World countries present a more stable business environment than the United States. Grassroots projects are nearly non-existent, while late-stage programs continue cautiously. Exploration activity continued at the following projects: Garnet, Pegasus Gold; Southern Cross, Asarco; Elkhorn, Goldfields; 7-Up-Pete, Phelps Dodge and Canyon Resources; Miller Mountain, Pegasus Gold; Sheep Creek, Cominco American Resources; Checkerboard, Kennecott and BHP Utah International; Emigrant Creek, Pegasus Gold; and Crevise, American Copper and Nickel. All mineral activity, whether on private, state or federal land, is regulated by the Montana Department of State Lands under three classes of permits - Small Miner Exclusion Statements (SMES), Exploration Licenses and Operating Permits. A total of 230 Exploration Licenses are active in the state with 26 of those being new. However, there are only 433 projects current in Montana, with many of those in the reclaiming stage. The majority of exploration projects consist of individuals expending time rather than money on properties. The number of mines functioning under operating plans declined by one when W.R. Grace closed its Zonolite operation.

Jan 1, 1993

By A. Ghosh

Commonly used predictors of ground vibration from blasting, being linear in log-log plot, do not model the underlying physics of wave attenuation. Amplitude of the wave decays with distance due to geometrical spreading and inelastic attenuation producing a nonlinear carve in log-log scale. The nolinear decay of seismic waves has also been observed from non-explosive sources, such as, pile driving, drop hammer, traffic, etc. The improved predictors, by explicitly taking these two mechanisms into consideration, model the data trend extremely well at all distance ranges. Actual field data from different studies have been used to validate the improved models.

Jan 1, 1991

By M. S. Ellis, D. J. Nichols

In 1999, 1,100 million short tons of coal were produced in the United States, 38 percent from the Northern Rocky Mountains and Great Plains region. This coal has low ash content, and has sulfur content in compliance with Clean Air Act standards (U.S. Statutes at Large, 1990). The National Coal Resource Assessment for this region includes geologic, stratigraphic, palynologic, and geochemical studies and resource calculations for 18 major coal zones in the Powder River, Williston, Green River, Hanna, and Carbon Basins. Calculated resources are 660,000 million short tons. Results of the study are available in U.S. Geological Survey Professional Paper 1625-A (Fort Union Coal Assessment Team, 1999) and Open-File Report 99-376 (Flores and others, 1999) in CD-ROM format.

Jan 1, 2001

The Golden Grove Project area is located 220 km (137 miles) east of Geraldton in Western Australia (Fig. 1). The project is a joint venture involving Amax Exploration (Australia) Inc. (Amax), Electrolytic Zinc Co. of Australasia Ltd. (EZ), and Esso Exploration & Production Australia Inc. (Esso), each with 31 116% interest, and Aztec Exploration Pty., Ltd. (Aztec), with a 3 1/2% carried and a 3% contributing interest. The venture covers two significant volcanogenic massive sulfide deposits and some 40 km (25 miles) of highly prospective Archean volcanics. During the course of the past 12 years (to 1983), all four companies were responsible for operating the project at one time or another and all influenced the discoveries. The Gossan Hill and Scuddles deposits are typical examples of volcanogenic massive sulfide deposits associated with Archean explosive submarine acid to intermediate volcanic complexes. They are located in the northwesterly trending Yalgoo greenstone belt of the West Australian Archean Shield. Gossan Hill, located in 1972, is essentially a copper deposit with minor zinc lenses; to date, 97 diamond holes have delineated a geological resource* estimated to contain 13 Mt (14.3 million st) of of 3.4% Cu and 13 g/t (0.38 oz per ton) Ag in the main lenses with minor lenses totaling 2 Mt (2.2 million st) of 3.7% Cu and 17 g/t (0.49 oz per ton) Ag and 1.7 Mt (1.9 million st) grading 1.5% Pb, 14% Zn, and 87 g/t (2.8 oz per ton) Ag. Scuddles is a zinc-copper deposit with gold and silver credits. It *Resource estimate provided by Esso for inclusion in Aztec Exploration Pty. Ltd. 1982 Annual Report was discovered in 1979 and, to the end of 198 1, had been delineated with 42 diamond holes. On the basis of this drilling, a geological resource* of 26 Mt (28.7 million st) has been estimated in three coalescing lenses. The lenses comprise 7.5 Mt (8.3 million st) of 2.1 % Cu, 12 g/t (0.35 oz per ton) Ag, and 0.3 g/t (0.009 oz per ton) Au; 7.6 Mt (8.4 million st) of 0.4% Cu, 9.9% Zn, 73 g/t (2.3 oz per ton) Ag, and 0.7 g/t (0.02 oz per ton) Au; and 1 1.0 Mt (1 2.1 mil lion st) of 1.1 % Cu, 9.3% Zn, 8 1 g/t (2.6 oz per ton) Ag, and 1.5 g/t (0.044 oz per ton) Au. Readers are referred to Frater (1978) and Harris et a). (1982) for a more detailed geological account of these deposits.

Jan 1, 1991

By Y. Akin

The floatability of a typical boron mineral, colemanite (Ca2B6O11.5H2O), is shown to be hindered by the presence of montmorillonite type clay minerals. The clay is found to act in the form of slime coating. The mechanism of slime coating is investigated using pure colemanite and clay and their mixtures with an anionic reagent in a microflotation cell. Adsorption, flotation, solubility, zeta potential and scanning electron microscope studies reveal that slime coating occurs through electrostatic attraction. It is possible to minimize the effect of slime coating either at high surfactant concentration or at high pH values.

Jan 1, 1997

The National Mining Hall of Fame will hold its 13thAnnual Induction Banquet during MINExpo International 2000 in Las Vegas, NV. The gala black-tie (optional) event will honor eight legendary leaders of the mining industry. The event will take place at the Las Vegas Hilton Hotel on Sunday, Oct. 8. The induction ceremonies will salute mining greats elected by the board of governors from a list of nominees submitted by mining industry partners and the public. The members of the Class of 2000 will join 151 other inductees enshrined in the Mining Hall of Fame in Leadville, CO. The evening will begin at 6 pm with a cash bar reception followed by the banquet and program at 7 pm. Keynoting the banquet program will be Harrison (Jack) Schmitt. He was the geologist/astronaut of the Apollo 17 mission to the moon in 1972 (see related story on page 26). And he is the only scientist to “kick rocks on the moon.” Schmitt is also a member of the Mining Hall’s board of governors. Schmitt was also the keynote speaker at the First Annual Induction Banquet in Denver, CO in 1988.

Jan 1, 2000