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By Fred N. Kissell, Robert J. Timko

Safe escape from coal mine fires continues to be a concern of the mining industry. The most life-threatening fires occur outby the working sections. Because stoppings always leak some air, an outby fire may in time cause intake escapeways to become contaminated with smoke and toxic gases. Smoke and gas infiltration into intake escapeways can be minimized by raising their air pressure over that of adjacent airways. This can be done by checking off the intake escapeway near the working face. The Bureau of Mines has investigated the use of a parachute stopping as a quick-erect check curtain during mine fires, and the concept has been tested in several mines. In every instance, when a parachute stopping was erected on the section, the intake pressure went up substantially. The pressure-raising effect of the parachute persisted for up to 1200 m (4000 ft) outby. Results indicate that checking off the intake escapeway may serve as a viable way to improve safety during mine fires.

Jan 1, 1991

FIRST TOWN PLANNING PROPOSALS Initially, accommodation at the minesite was provided at the Pastoral Homestead situated some seven kilometres north-east of the mine and between 1963 and 1966 was the base of the exploration camp. Tents were used for sleeping of 100 men and the Homestead used for dining and office facilities. With the beginning of ore production and shipment due to commence in 1969 a permanent town location was sought. Early town planning studies had been commissioned by Amax Inc. and Colonial Sugar Refining Co. Ltd. and in 1967 The Broken Hill Proprietary Company Ltd. took over the responsibility for putting them into effect. The location chosen was about four kilometres due east of the mine. Certain dominant factors influenced this choice. It was near enough to the mine to share services, yet far enough away not to be affected by dust and noise and received the additional shelter of a range of hills separating it from the mine. A predominant slope to the east provided good drainage and the ground was easy to excavate for services.

Jan 1, 1976

A remarkable industrial renaissance is underway in the People's Republic of China (PRC), says USBM's Dr. K. P. Wang in his recently released 96-page report on "The People's Republic of China-A New Industrial Power with a Strong Mineral Base." Dr. Wang's summary of the current mineral position of the PRC includes many insights into its future potential and trade possibilities with the West.

Jan 2, 1976

Uranium minerals were found in Australia as early as 1869, but it was not until the 1940's that a search specifically for uranium was begun. Instrument types and techniques used in early exploration are still used today, but have been developed into more sophisticated and portable types. Recent improvements in exploration have been the introduction of the gamma ray spectrometer, radon sampling and geochemical surveys. The environments of presently defined uranium deposits are predominantly sedimentary. Known deposits in igneous environments are usually small. The size of targets which are likely to provide economic deposits is of the order of 10,000 tons U308, producible at a cost of less than $10 per pound. Such targets are most likely to be in Precambrian sediments or in granitic masses. Recent exploration in Australia has included investigation of Precambrian sediments, Precambrian and Palaeozoic granites, Mesozoic and Tertiary sediments, Precambrian volcanic rocks and brecciated masses of unknown age. The origin and method of emplacement of uranium in these environments is not well known but there are indications that syngenetic sedimentary processes are important, and volcanic rocks may make a major contribution to the supply of uranium.

Jan 1, 1970

By E. D. Williamson

DURING the wartime rush to prepare the glass necessary for the needs of our army and navy, the problem of the temperature control of the annealing kilns became most serious. The narrow limits of strain allowable (all the specifications called for less internal strain than the average of the previously used German glass) made necessary a very exact procedure and the methods had to be used on a much larger scale than theretofore. At the Charleroi plant of the Pittsburgh Plate Glass Co., the members of the staff of the Geophysical Laboratory, which was cooperating with the company, had occasion to study the methods available, and reached a number of conclusions (many of them by no means new except in their application) that may interest and assist those who have to meet similar problems in other fields. The following is a short account of the essential features of the system of temperature control evolved, along with a rather abridged statement of the reasons that led to the adoption or rejection of various schemes.

Jan 8, 1919

By Werner Langguth

SINCE the introduction of the improved method of precipitating gold from chlorine solution by SO2 and H2S at the Golden Reward chlorination-works, Deadwood, S. D.,* this modern method has been further adopted in the chlorination-works of the Portland Consolidated Company at Deadwood, and in those of the Black Hills Milling and Smelting Company at Rapid City, S. D. It has proved practically most successful in the handling of large quantities of gold solution, and constitutes up to date, with Mr. John E. Rothwell's most important improvement, namely, barrel-leaching under hydraulic pressure, the principal progress made in gold chlorination. The method of refining the gold sulphides which result from this method of precipitation, was introduced by me in 1890 at the Golden Reward works, and in 1892 at those of the Black Hills Company. It has not suffered any changes during the last three years, and is substantially as described below:

Jan 1, 1895

By Jim Petrunyak, Conny Postpack

The authors describe in this paper a systematic approach toward reducing coal production costs up to 35% through the use of explosives energy for overburden removal. In this system, explosives are employed to blast as much as 65% of the overburden instantly from highwall to spoil pile, with only the lesser portion requiring removal by dragline, shovel, or loader.

Jan 1, 1983

By I. Nishkov, L. Alexandrova

The kinetics of froth flotation and the three-phase contact (TPC) parameters are studied at temperatures varying from 20°C to 40°C. The material floated consists of glass spheres and a quartz particles with various diameters. Dodecylamine hydrocloride (DDAHCI) is used as a collector. The equilibrium three-phase contact angle is measured with a microscope technique using the modified Mingins-Scheludko method. Using a Wilhelmy method, the temperature effect on the surface tension of the DDAHCI solution is determined. The formation of the thin film on a polished plate of vitreous silica and the expansion of TPC is monitored by means of a metallographic microscope and recorded on a attached camera at different temperatures. The experimental data show an intensification of the flotation kinetics at 30 and 40°C in the case of small particles. Such an intensification is not observed with the larger particles. The cause for intensification of the flotation kinetics is sought for in the dependence of the TPC rate of expansion and induction time on temperature.

Jan 1, 1995

By H. D. Freeman

The Pacific Northwest Laboratory (PNL) is developing cover technology for uranium mill tailings that will inhibit the diffusion of radon to the atmosphere. As part of this cover program, an improved radon flux measurement system has been developed. The radon measurement system is a recirculating, pressure-balanced, flow-through system that uses activated carbon at ambient temperatures to collect the radon. With the system, an area of 0.93 m2 is sampled for periods ranging from 1 to 12 h. The activated carbon is removed from the radon trap and the collected radon is determined by counting the 214Bi daughter product. Development of the system included studies to determine the efficiency of activated carbon, relative calibration measurements and field measurements made during 1980 at the inactive tailings pile in Grand Junction, Colorado. Results of these studies are presented.

Jan 1, 1981

By Hassan El-Shall, M. N. Ahmad, Ponisseril Somasundaran, C. R. Holland, G. M. Walker, N. Iles, R. D. Chandler, Regis Stana, B. Duddy, Patrick Zhang

Phosphoric acid is a major raw material for the production of ammonium phosphate (AP) that is used as an intermediate in fertilizer production. Impurities within commercial grade wet process phosphoric acid are important in producing a fertilizer granule with good handling properties. The impurities identified as being important are; iron (III), aluminium and fluorine-containing compounds. Results show that the viscosity of the AP slurry produced increases by increasing the amount of impurity in the acid. Bench scale tests have been successfully replicated on a plant scale leading to a better understanding of the composition of impurity levels within phosphoric acid required to produce a high quality, free flowing, hard, spherical and non-caking granular fertilizer.

Jan 1, 2002

Increased world consumption of crude and products coupled with the trend toward supplying this demand from the nearest and most economical source of supply had the economic effect of broadening the demand for Venezuelan crude. As a result of this, Venezucla produced more in 1934 than in 1929, the previous peak year. During 1934 Venezuelan output is estimated at a total of 139,382,000 bbl., a daily average of 381,868 bbl., against 120,442,000 bbl. in 1933, a daily average of 329,978 bbl. This is an increase of 51,890 bbl. per day. It is interesting to note from the comparison of production for the past 10 years (Table 1) that in spite of the fact that Venezuela produced more in 1934 than in 1929 its share of world production is slightly less than in 1929 and 1930. During the latter part of 1934 Vcnezuela produced its first billionth barrel of crude. Only three other crude-producing countries of the world have attained this distinction; namely, United States, Russia and Mexico. Venezuela still ranks third in the producing countries of the world, being surpassed by the United States and Russia. Exports of crude and products from Venezuela for 1934 are estimated at 133,400,000 bbl. This is an increase of 16,107,000 bbl., or 13.73 per cent as compared with 1933.

Jan 1, 1935

Jan 1, 1935

Feasibility studies in the development of mining projects are fundamental to most investment decisions. It is important that the issues addressed and the degree of detail involved in feasibility studies are consistent with the investment decisions to be taken. Emphasis should be placed on a thorough analysis of critical project parameters prior to detailed investigations being undertaken into other activities which are not relevant to the decisions at hand. Therefore, the issues to be decided upon should be influenced significantly by the stage of development of the project and by the reliability of technical and financial information used in the study. Some of the more critical parameters of feasibility studies are commodity prices, inflation rates and discount rates. Advice is given on the selection of these inputs and also on their application in the feasibility study as the project progresses through its various development stages. The feasibility study should involve not only a formal evaluation of project economics but also an analysis of all project related risks and a comparative analysis of projects competing in

Jan 1, 1983

CABS - Costs and Budget System - is being developed to provide more appropriate tools to assist cost control. The most important of these tools is responsibility accounting, that is to ensure the respons- ibility for costs and budgets is placed at the lowest possible managerial level in the Company. The system design and computer techniques utilized include the use of on-line facilities for enquiry purposes plus entry and validation of data. Data base management is used to permit the complex relationships that exist between data in CABS to be defined and maintained. The system must be flexible in order to cater for organisational and other maintenance changes with minimum time delays. The major outputs of the system are reports produced in several cost dissections, by responsibility, by products by cost collection group and type of expense. A significant role in CABS has been played by users. This includes development, control and review of the system proposals in order to ensure that the objectives and requirements from all sections in the Company are met. This role has included Project Leader for the system plus a committee formed to provide formal acceptance of the system Design.

Jan 1, 1977

By John D. Morgan, Sylvain J. Pirson

AN instantaneous and continuous analysis of a mineral suspension should be of great value in controlling various mineral preparation processes. Described herein is a method of analysis based on the use of high-frequency alternating current, which, under certain restrictive conditions, could be of use. THEORETICAL CONSIDERATIONS In a suspension of conductive minerals, the electrical effect primarily responsible for the variations in electric conductivity is the capacitance. In Fig Ia, let an alternating voltage E be applied across two electrodes F and F', between which are two rows (S and T) of mineral particles, all of approximately the same size, immersed in a fluid. Let the number of rows of particles between the electrodes be R and the number of particles in each row be N. If A is the area of a particle, D is the distance separating two particles, and K is a constant depending on the fluid, the capacity, Co, of the particle system will be given by: [KRA C0 ND] Referring now to Fig Ib, let R, the number of rows, be held constant, but let N, the number of particles in each row (S and T), be increased X-fold. The capacity, C1, of [ ]

Jan 1, 1947

By D. Koch

Bentonites and bentonite containing sealing materials are used since many years for sealing purposes in foundation, dike construction, hydraulic engineering and landfill construction, especially for encapsulation of old waste deposits In the near future compacted bentonites will be important components of multi-barrier systems for dry charge of old mines, for underground disposal of hazardous or radioactive wastes. Because of their exceptional physical, structural and chemical properties, bentonites are offering manifold possibilities to protect the environment against the negative effects of dumping grounds. Often the compliance with legal regulations for waste dumping or the isolation of contaminated areas is possible only by using bentonite containing sealing systems. The essential properties of bentonite, bentonite containing building materials and the different techniques of making horizontal technical base liners and vertical cut-off walls are explained. For horizontal technical base liners the adsorption ability, the ion exchange capacity and the swelling behavior of bentonites are important. For cut-off walls bentonite controls the rheological behavior of the slurry and is responsible for the low permeability of the hardened bentonite-cement-wall. In the multi-barrier systems of repositories for chemical or radioactive wastes compacted bentonites are considered to be favourable sealing and backfilling materials because of their high swelling capacity, their adsorption and ion-exchange ability and their plasticity in water saturated state.

Jan 1, 2005

By G. A. Munoz, J. D. Miller

Gold leaching of an auriferous pyrite ore from the Portovelo deposit in Ecuador indicates that noncyanide leaching systems, such as thiocyanate and thiourea, are not as effective as the traditional cyanide system. For example, whereas approximately 95% of the gold can be leached from the ore with cyanide, only about 50% gold dissolution can be achieved with a thiocyanate leaching system. Electrochemical measurements indicate that gold is not cathodically protected by pyrite in these systems. Based on the results of preliminary diagnostic experiments, it appears that gold dissolution in thiocyanate and thiourea systems is limited by passivation due to the formation of either elemental sulfur or sulfur compounds on the gold surface.

Jan 1, 2000

By L. A. Panek

When rock is subjected to a load it is deformed. Ordinarily this is observed in a mine as the displacement of one point with respect to another-the deflection of the roof, which may be observed as a convergence between roof and floor; or the extrusion of material from the rib, which may be observed as a decrease of the distance between the rib and the post of a timber set. The effect of excessive pressure may be a rockburst if the rock is strong, or it may be "squeezing" ground if the rock is "soft". Some desirable effects of high stress (high in relation to strength) are the caving of roof in a longwall mining operation, the caving of ore in block caving, and the decrease in mechanical energy required to break down the mineral seam in a retreating pillar-robbing operation. In any case, whether the observable effect of rock load is desirable or undesirable, it is a displacement, and depends on the following four factors:

Jan 3, 1961

By D. S. Yantek, R. J. Matetic, A. K. Smith, E. D. Thimons, J. Srednicki

In a 2007 report to the U.S. Congress, the Office of Mine Safety and Health Research of the U.S. National Institute for Occupational Safety and Health (NIOSH OMSHR) stated that built-in-place refuge alternatives (BIP RAs) provide significant advantages over mobile refuge alternatives. At present, the requirement to locate refuge alternatives within 305 m (1,000 ft) of working faces makes BIP RAs impractical in most coal mines. BIP RAs would be practical if three issues are addressed: (1) allowing BIP RAs to be located at greater distances from the working face, (2) developing a reliable process for the design and approval of BIP RA stoppings that meet the 0.1-MPa (15-psi) design criteria, and (3) developing systems that reliably deliver breathable air to the refuge alternative. In 2015, NIOSH OMSHR conducted a study of these three issues and issued a report. In the report, justification was provided for allowing the placement of BIP RAs at greater distances from the working face than the currently mandated 305 m (1,000 ft), guidelines were developed that could be used by industry when submitting BIP RA stopping design applications for approval which are patterned after the Mine Safety and Health Administration guidelines for coal mine seal design applications, and insights were provided into options for providing a reliable supply of clean, breathable air to BIP RAs. This paper presents a summary of the study’s findings and also addresses issues discovered during the building and designing of a BIP RA that OMSHR researchers constructed in NIOSH’s Experimental Coal Mine in Pittsburgh to research the testing and improving of BIP RAs. These issues include several issues related to the delivery, distribution and exhaust of ventilation air to the BIP RA and some general construction issues that require further investigation.

Jan 1, 2016

By Y. J. Son, S. S. Nageshwaraniyer, K. M. Kim

"This paper reports on the development of a simulation-based framework for obtaining optimal blast design parameters for a hard-rock mine. To do this, a conventional medium-sized hard-rock mine was taken as a case study. The mine has two pits containing hard and soft rock types. The proposed framework contains a combination of regression analysis using Excel software by Microsoft and discrete-event simulation using Arena software by Rockwell Automation, applied to construct a model of the material-handling network of the mine. Specifically, blasting parameters are estimated by Excel-based regression analysis, processes including blasting and haulage from pits to crushers are modeled by a Forward Blasting simulation submodel, and material-handling operations including crushing, storage in stockpile, and haulage via conveyors and into SAG and ball mills are modeled by a Crusher to Ball Mill simulation submodel. A Reverse Blasting submodel is then used to obtain the optimum blast design corresponding to a target P80 particle size. Using the proposed framework, an economic analysis was performed to demonstrate the cost savings that could be realized for each rock type as a function of specific explosive energy. IntroductionIn a modern hard-rock mine, various processes such as drilling, blasting, crushing, grinding and mineral liberation are optimized to increase productivity, a practice known as mine-to-mill (MTM) optimization. Blasting is important in MTM optimization as it is the first comminution process and has an impact on all downstream processes (Julius Kruttschnitt Mineral Research Centre, 1996; Nielsen and Lownds, 1997; Nielsen and Malvik, 1999; Chung and Katsabanis, 2000; Kim and Kemeny, 2011a; Kim and Kemeny, 2011b).Two main research topics have emerged in the area of blasting design: (1) identifying the optimal target blast fragmentation at each shot and (2) controlling the blast fragmentation for that target. As part of an MTM optimization study, Kim and Kemeny (2011a; 2011b) developed a site-specific blast fragmentation prediction model that can be used to identify the target blast fragmentation and can be incorporated into MTM optimization. They also reported methodology for assigning model parameters easily and with minimal human bias."

Jan 1, 2015