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By Frederick B. Brien

For many years tin mining in Bolivia has been very important to the economy of the country. In recent years the tin content of the ore reserves has been steadily declining. An improvement in concentration efficiency is highly desirable in order to increase productivity from the present-low-grade mine ores and to allow retreatment of the many millions of tons of tailings from past operations, some of which equal the present ores in tin content. A number of investigators have been or at present are working on various phases or approaches to the problem. Gravity concentration is used in Bolivia today as it has been in the past to recover tin minerals from the mine ores. An objective of the work reported in this paper was to examine the possibility of treating present low-grade ores and sink-float tailings products, at a relatively coarse grind, in order to produce a higher grade feed material to the present gravity concentration plants. The possibility of using heavy liquids in cyclones to treat large tonnages with a minimum of outlay presented itself and is of particular interest since appropriate heavy liquids are available and with physical properties which lend themselves to simple recovery methods. Tests were carried out using a closed circuit laboratory cyclone assembly. It was desirable to determine the value of using the SG50 concept and Tromp curves for analyzing the cyclone concentration test results. The effects of entrained water on the behavior of ore particles in the cyclone were examined.

Jan 1, 1964

By E. J. Karges

[For reasons well known to Mining Engineers, fine grinding in the wet form is quite universal inn plants engaged in the traction of metallic values from crude ore In the processing, of non-metallic and industrial minerals, however, fine grinding in dry form is the more common method. The crude materials generally contain less moisture than required for wet grinding, and the products are usually marketed or used in the dry form, most of them as powders. To grind wet would therefore entail the addition of water and the expense for drying the product, which is not justified. This paper will concentrate on the particle size reduction or fine grinding of materials to produce a dry powder]

Jan 1, 1963

By John B. Goddard

Crystallization of ammonium paratungstate (APT) is frequently the last effective purification step in producing high-purity tungsten. However, crystallizer mother liquors are often several times higher in tungsten than predicted by the solubility of APT. The formation of heteropoly anions, particularly those containing phosphorus and silicon, is largely responsible. Solubility of tungsten in APT mother liquor can be linearly correlated with the concentration of these and other impurities. The problem can be overcome by direct treatment of the crystallizer feed solution with alum. By appropriate treatment, the aluminum hydroxide flocculates and is easily filtered, resulting in a purified low-aluminum crystallizer feed from which high APT yields can be attained.

Jan 1, 1984

By Ayokunle Adewale Akinlalu, Sunday Bayode, Sherif Olumide Sanusi, Joshua Oluwagbenga Adeboye

Gold occurrences have been reported in Alagbede, southwestern Nigeria, but a mineral potential map (MPM) to guide academics and investors in the area is still needed. As a result, geophysical methods (aeromagnetics and aero-radiometry) have been used to assess the potential for gold minerals in the area. Several enhancement filters, such as reduction to the equator, upward continuation, analytical signal, second vertical derivative, and power spectrum analysis, were applied to the aeromagnetic data to understand the subsurface geology better. The enhancement filters applied to airborne radiometry data are K/eTh, ternary color composite, F parameter, and deviation from the ideal K values (Kd). Geophysical data analysis was used for structural mapping and geological reconstruction, while aero-radiometric data was used for hydrothermal alteration mapping. The primary trend observed in the area’s magnetically inferred structural framework map is NE-SW, while a few are in the NW–SE and E-W trends. These observed trends show that the study area suffered at least three deformation episodes. Geological evidence of gold mineralization, such as favorable lithology, geological structure, and hydrothermal alterations, has been fused to produce a reliable MPM of the area. The geographical location of the existing mineral sites in the investigated area agrees with the geological structures and the MPM produced there. Thus, the systematic approach adopted in this study can be extended to other supracrustal belts of a typical Precambrian basement complex worldwide to ensure the reliability of orogenic gold mapping and resource management.

May 9, 2023

By Neall. George M.

No method of roof control yet devised has proven to be universally acceptable for the wide range of strata conditions experienced in U.S. coal mines. However, a relatively new innovation, the roof truss, has proven itself capable of preventing roof failures which both conventional and resin bolting could not. Presently, the economics of roof trusses are not favorable when compared to bolting due primarily to drilling and installation procedures, but this is expected to change with improved truss and equipment designs. To realize the full potential of this new method of roof control, design criteria are needed which can optimize the effect of the truss for varying strata conditions. A review of the literature reveals that some work has been conducted on the roof truss. 1 Gambrell and Haynes (1970) showed that the roof truss is superior to angled roofbolts installed through a header. Sheorey, Verma, and singh2 (1973) used statics to prove that the optimum angle of inclination should be greater than 450? However, to date, no systematic attempt has been made to establish design criteria. In this report, the problem was approached in three ways. First, model studies were performed to determine general trends of truss support as a function of a number of variables. This provided a better understanding of the support mechanism involved. Secondly, beam theory was employed to calculate the actual support capacity of a truss, realizing the many simplifications, assumptions, and shortcomings of this approach to such a complicated problem. Last, field testing will be utilized to test the hypotheses previously developed and provide hard data to further synthesize roof truss design criteria. Field testing has recently commenced and should be complete before mid 1977.

Jan 1, 1977

By Carl Rampacek

Laboratory and small-scale continuous pilot-plant investigations made at the Tucson Metallurgy Research Laboratory of the Bureau of Mines have demonstrated that the copper segregation process is applicable to the treatment of oxidized and mixed oxide-sulfide copper ores regardless of the gangue constituents. The process comprises heating the ore to a temperature of 750° C. with small quantities- of sodim chloride and coke to produce metallic copper, which then is recovered by flotation. Tests were made on' 23 copper ores of different types containing 0.8 to 5 percent Cu, .The copper recoveries ranged from 73 to 96 percent in concentrates assaying 10 to 62 percent Cu, depending on the grade and type of ore, The direct operating cost for a 1,000-ton-per-day furnace and flotation plant is estimated at about- $3 per ton of ore.

Jan 1, 1960

By Pier Francesco Paglini, Gian Luca Menchini, Pier Francesco Boschi

"PROJECTThe “Caltanissetta” Tunnel is part of the ANAS S.p.A (National Autonomous Roads Corporation) $ 1.3 Billion Highway 640 Caltanissetta-Agrigento (Sicily, Italy) Rehabilitation Project, consisting in upgrading of 62 km (40 miles) of highway. The Italian multinational construction company Cooperativa Muratori & Cementisti di Ravenna, is the General Contractor for the design and build contract. The highway S.S. 640 starts from Porto Empedocle, to the intersection with the Motorway A 19 Catania-Palermo.The entire project, double carriageway designed for speed 70-120 km/h and maximum longitudinal slope of 4.2%, is divided into two sections. First Section: just finished and opened to traffic. Second Section: mainly involving the province of Caltanissetta, length about 28 km (18 miles), works started in 2013. This second section includes the most challenging work of all the project, the “Caltanissetta” tunnel consisting of two separate tubes, each with 3.9 km length and inside diameter of 13.50 m, in order to host 2 traffic lines and an emergency line. HORIZONTAL AND VERTICAL ALIGNMENT - GEOLOGY AND HYDROGEOLOGYThe plan alignment of “Caltanissetta” tunnel is formed by two tubes which are located at a minimum mutual distance of 22 m to a maximum of 63 m, with n. 9 pedestrian and n. 4 road cross passages; ventilation shafts are not provided. Overburden over portals area is about 5 m till a maximum of 120 m. Tunnel sections have variable longitudinal slope from 2.6% to 0.5%, transversal slope of about 3.5%. Right tube length is 3,992 m, left tube length is 3,877 m."

Jan 1, 2016

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 G. Zain, Abdel-Zaher M. A. Abouzeid, Y. S. Mustafa, A. A. S. Seifelnassr

The main forces acting on minerals in conventional size reduction units are compression, impact, attrition, and/or abrasion. Usually a combination of these forces shares the breakage action of the minerals with one or more of these forces dominating the breaking action, depending on the machine used. The present work concentrates on the behavior of quartz when stressed with compression force in a confined piston die. Several size fractions within the size range minus 10 mm to plus 0.85 mm were compressed in the piston die. The measured parameters are compression load, bed thickness, displacement as a result of compression, rate of displacement, and the size distribution of the products. It was found that the size distributions are, to some extent, different from those produced by the ball mill or the high-pressure roll mill. This is mainly because of the differences in the type of the acting forces in each case. It was also found that the cumulative weight of the distributions is reasonably normalizable with respect to the median particle size of the product. The specific energy expended is inversely proportional to the median size of the products, and the reduction ratios, xf/xp, are directly proportional to the applied compression force, and hence, to the specific energy expended. A simple model is suggested for predicting the particle size distribution as a function of the expended energy. The calculated values of the size distributions match fairly well with the experimental values, except at the very low energy levels, where most of the energy expended is consumed in the rearrangement and packing of the particles in the confined space with little or no breakage.

By D. B. Sikka, R. B. Bhappu

Porphyry-type copper-molybdenum (Cu-Mo) deposits typically occur in the Phanerozoic rocks and have been well-documented. During the past two decades, a number of porphyry-type Cu-Mo deposits that range in age from 1055 Ma to 2970 Ma have been identified in the Precambrian rocks of Australia, Canada, China, Finland, India. Namibia and Zambia. The Malanjkhand porphyry copper deposit M.P., India is estimated to contain 789 Mt (870 million st) averaging 0.83% copper (mill headgrade); 0.004% molybdenum; 0.2 g/t (0.006 oz/st) gold; 6 g/t (0.175 oz/st) silver and a cap of 7.5 Mt (8.2 million st) of oxide ore averaging 0.8% copper. The economic potential of the expanded copper mining milling, smelting and refining complex is expected to yield cathode copper 118.6 kt (130,700 st); molybdic oxide 830 t (914 st); gold 1.9 t (61,732 oz); silver 46.6 t (1.5 million oz); sulfuric acid 240 kt (264,500 st), copper from leach dumps 11.5 kt (12,600 st); nickel 24 t (26,400 st); cobalt 84 t (92,600 st); bismuth 16 t (17.6 st); selenium 48 t (53 st), tellurium 4.8 t (5.3 st).

Jan 1, 1995

By Jeff Reid, Mohamed Maghari, Nicholas Joens

The Burnaby Mountain Tunnel was an integral part of the Trans Mountain Expansion Project. General Contractor, Kiewit Ledcor TMEP Partnership (KLTP), contracted with McNally Construction to build an underground tunnel between the Burnaby and Westridge Marine terminals under Burnaby Mountain. The pipeline was constructed within a 2.6-kilometre tunnel, eliminating the need to run the pipeline over the mountain and minimizing community impacts. The complexities of this Project led to multiple innovations, including the design of a Tunnel Boring Machine (TBM) capable of excavating through mixed-faced conditions concurrently thus allowing the Project team to complete the tunnel with limited geotechnical information.

Jun 23, 2024

By Karl R. Zipf

A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine. The gas samples are drawn via vacuum pump to the surface and are typically analyzed for oxygen, methane, carbon dioxide and carbon monoxide. Results of the gas analyses are displayed and recorded for further analysis. Trends in the composition of the mine atmosphere, such as increasing methane or carbon monoxide concentration, can be detected early, permitting rapid intervention that prevents problems, such as a potentially explosive atmosphere behind seals, fie or spontaneous combustion. TBS is a well-developed technology and has been used in coal mines around the world for more than 50 years. most longwall coal mines in australia deploy a TBS, usually with 30 to 40 monitoring points as part of their atmospheric monitoring. The primary uses of a TBS are detecting spontaneous combustion and maintaining sealed areas inert. The TBS might also provide mine atmosphere gas composition data after a catastrophe occurs in an underground mine, if the sampling tubes are not damaged. TBSs are not an alternative to statutory gas and ventilation airflowmonitoring by electronic sensors or people; rather, they are an option to consider in an overall mine atmosphere monitoring strategy. This paper describes the hardware, software and operation of a TBS and presents one example of typical data from a longwall coal mine.

May 1, 2013

By S. M. Carpenter

In an ever increasing ?carbon? society; management and growth will be measured by one?s carbon footprint (or output). Industries, especially mining, are under an ever increasing scrutiny of carbon, water and environmental mandates. These mandates are measured by the emissions caused by the combustion of fossil fuels. The fundamental building-block for any business, strategic or management decision must be based on an understanding of one?s ?footprint?. The scrutiny is most stringent for the commodities producers, power producers & fuel suppliers in the energy market. An overview of currently acceptable standards, application of those standards and nuances experienced in collecting the data necessary to analyze and complete a company?s carbon footprint will be presented. A lack of regulation, the fear and expectation of new and ever constraining rules, regulation and a change in the federal administration is a recipe for uncertainty in the marketplace.

Jan 1, 2010

By John Fred Rivera

Since its inception during the hectic days of World War II, Kaiser Steel Corporation has developed and maintained a solid reputation as a progressive company with an incessant penchant for attempting innovative ideas to improve its stature in the American and world corporate framework. The very latest in technology is aptly demonstrated in the new Basic Oxygen Process recently placed into operation at Kaiser's huge Fontana Steel Mill. Daring ventures such as this and other developments on pollution control devices have propelled Kaiser Steel Corporation into the forefront as the largest steel producer in the western United States. Kaiser Steel's boldness and willingness to attempt new ideas and the very latest in technology is by no means limited to its steelmaking operation. It extends into every phase of Kaiser's corporate structure.

Jan 1, 1979

By A. B. Cecala, G. W. Klinowski

Introduction The US Bureau of Mines has designed and evaluated total mill ventilation systems (TMVS) at two mineral-processing operations. Both systems have proven proficient at cost-effectively reducing respirable dust levels throughout the mills. An 11.8-m3/sec (25,000-cfm) system installed at a clay-processing mill provided about 10 air changes per hour (acph). This system reduced respirable dust concentrations by about 40% throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 23.6 and 47.2 m3/sec (50,000 and 100,000 cfm) of ventilation to the mill building, corresponding to 17 and 34 acph. Average millwide respirable dust reductions were 36% and 64%, respectively. This work was done to determine general guidelines and design criteria for operations that may be interested in implementing TMVS. TMVS should be designed to draw clean make-up air in near the base of the mill. This air provides general purging and may clear some dust-laden areas throughout the mill structure. It is discharged at or near the top of the structure. Without the TMVS, dust can exit the building through open doors, windows, etc. and contaminate outside plant workers. This dust can also be recirculated back into the mill building causing additional contamination problems. TMVS is not a stand-alone system. It is a supplemental technique to assist other localized dust control systems (Mody et al., 1987). Testing Total mill ventilation systems were evaluated at two processing operations. For both tests, the primary goal was to determine the reduction in respirable dust throughout the structure. Test site No. 1. The first evaluation was performed at a clay-crushing and screening mill in New York. The mill's base dimensions were 39.6 x 9.8 m (130 x 32 ft), giving a volumetric capacity of 4250 m3 (150,000 cu ft). The TMVS was designed to provide 12 m3/sec (25,430 cfm) of ventilation air to the mill, representing about 10 acph. This was accomplished by three 4 m3/sec (8475 cfm) roof-powered exhaustors that were evenly spaced across the roof. Three wall louvers provided inlets for make-up air at the mill's base. Two evaluations were performed at this mill. The first occurred for two days in December when outside air temperatures ranged from -12.2° to 4.4° C (10° to 40° F). Temperatures with the wind chill factor dropped as low as -34° to -40° C (-29 to -40° F) during the early morning. The second evaluation was in April when outside air temperatures ranged between 10° to 26.7° C (50° to 80° F). These two evaluations verified the effectiveness of TMVS in lowering respirable-dust concentrations throughout the mill. Gravimetric-sampler respirable-dust concentrations in December ranged from 0.22 to 2.39 mg/m3 under normal conditions, compared to 0.13 to 1.55 mg/m3 with TMVS. In April, respirable dust concentrations ranged from 0.29 to 4.84 mg/m3 under normal conditions compared to 0.21 to 2.37 mg/m3 with the system on. TMVS also increased visibility throughout the mill building. Dust reductions for gravimetric and RAM-I instruments are listed in Table 1. Each value was determined by comparing the average concentration for the entire day of testing for normal and TMVS values. The mean/standard deviation values for gravimetric and RAM-1 results were 42.5/17.6 and 37.1/16.8, respectively.

Jan 1, 1996

By J. J. Gusek, J. T. Gormley, V. Scovazzo

Glenrock, WY is underlain by two abondoned coal mines. Subsidence events have been recorded over the years, with the frequency increasing in recent years. As part of Wyoming's Abondoned Wins Lands Program, investigations including mining history/methods/mappings, subsurface drilling and material site searches were performed. Portions of the mines less than eighty feet from the surface, were identified as probable for subsidence. Subsidence control by hydraulic backfill was selected. Design included search and injection boreholes, water supply from the mines and the slurry mixing, transport and injection system. Injection system performance and backfill success is king monitored during construction.

Jan 1, 1986

By G. Schriever, H. Thiel, E. J. Foell

A long-term, large-scale, disturbance-recolonization experiment with relevance to the environmental effects of deep seabed mining is described. The study is funded by the German government and was launched in the abyssal eastern tropical South Pacific Ocean in February-March, 1989. After obtaining pre-impact baseline environmental data, a 10.8 km2 (4.2 sq miles) circular area of seafloor was disturbed using a specially designed "plow-harrow" device. An initial post-impact sampling series was carried out immediately after disturbance followed by a second post-impact sampling series six months after the disturbance. Plans call for repeated visits to the site at two year intervals to monitor the anticipated slow recolonization process until the area is inhabited by a new, stabilized community.

Jan 1, 1993

By Joel L. Morrison

The preparation of coal-water slurry fuel (CWSF) has the potential to be a commercially viable technology for the coal industry. The technology base required to prepare stable CWSF using grinding circuits has been developed over the past decade and is now being applied to the preparation of CWSF from wet coal fines which are generated during coal beneficiation. When preparing CWSF, the optimum CWSF formulation must be determined to ensure that the fuel will be stable while having acceptable atomization and combustion properties, and the production run must be monitored closely to ensure that the CWSF quality is maintained. This paper describes the CWSF formulation process, CWSF preparation circuits, and some of typical problems encountered in, and solutions to, the transportation and storage of CWSF.

Jan 1, 1993

By J. E. Friant

The Mini-Disc TM cutter drill bit is a radical design departure from the traditional tri-cone rock drill bit. Miniature disc type cutting tools as small as 3.25 inches (82.5 mm) diameter are fitted to a bit body to cut individual concentric kerfs. The action is the same as that commonly used on large tunnel boring machines but miniaturized. The high performance rate and efficiency of a disc cutter are the result of producing a large proportion rock chips rather than sand or powder. The Mini-Disc TM drill bit, referred to as the "Disc Bit" has other unique features as well. It can be re-greased between runs. It can be rebuilt in the field in about 15 minutes, cutters can be replaced and the Disc-Bit appears to require less down hole hydraulic power than conventional bits. Thoroughly tested in the laboratory, the bit has recently been undergoing field trials in well drilling, blast hole drilling and shaft drilling. As any engineer knows, the laboratory cannot shake out all the problems but it eliminates the more glaring weaknesses. Performance results have been exhilarating, and a few mechanical problems were discovered and largely overcome. This paper is a progress report.

Jan 1, 1999

By QUANWEN PU, Yonggang Wei, Bo Li

The spent catalyst is one of solid waste resources, which contains precious metals with considerable recovery value. However, due to the different compositions of catalyst, the recovery process is difficult. Most of the catalysts are supported by alumina which has good alkali-soluble properties, while platinum is insoluble in alkali. Platinum is enriched by pressurized alkaline solution which is a kind of hydrometallurgical process. The novelty of this study is the separation of alumina and platinum from the spent catalyst and the enrichment of platinum in the solid phase. In this study, a leaching process using NaOH as leaching agent under high temperature and pressure was employed. The effects of alkali concentration, leaching temperature, leaching time, and liquid–solid ratio on leaching efficiency were investigated. The optimum process conditions were determined as follows: alkali concentration of 240 g/L, temperature of 200℃, pressure of 1.20 MPa, time of 1 h, liquid–solid ratio of 5:1. It was concluded that the leaching rate of alumina can reach 99.69%. The content of platinum increased from 0.1749 to 21.12%, the loss of platinum was 3.39%, and the enrichment ratio of platinum increased by 120.82 times. The leaching kinetics of alumina was studied based on the shrinkage core model. The activation energy of alumina leaching is 19.53 kJ/mol, and the leaching process is controlled by chemical reaction. Pressurized alkali solution can not only efficiently leachate alumina from the spent catalyst and enrich platinum, but also reduce the reaction time and increase reaction rate.

Feb 11, 2022