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The annual reports of the supervising engineers of the seven sections comprising the Mining Division are assembled in the following pages and constitute the annual report of the division. In planning activities, the aim has been to adapt the work to changing conditions and needs of the mining industries and to avoid becoming bound to any particular type of investigation when others are found to be of more pressing interest.

Jan 1, 1939

By Pedro Lilienfeld

This report describes the development, design, fabrication and testing of a port-able, battery-operated, light scattering monitor (henceforth to be designated as ILSDM) for the rapid measurement of the concentration of respirable dust in mining environments. This instrument incorporates state-of-the-art design characteristics and makes use of advanced solid-state components both for light emission as well as for its detection. The use of a pulsed light source combined with synchronous signal detection minimizes drift problems and optimizes the sensitivity of the measurement. Simplicity of operation, reliability and ruggedness, light weight as well as improved performance were salient objectives of this instrument development program. Continuous clean-air flow screening of all critical optical surfaces, and optimized optical detection and electronic signal processing design resulted in about a hundred-fold decrease of noise and drift with respect to precursor instruments. Equivalent mass concentration measurements 88 low as 10 micrograms per cubic meter can be routinely performed with time constants of about 2 second.

Jan 1, 1979

By William J. Wuest

This U.S. Bureau of Mines report presents an overview of ground control considerations associated with floor heave. Factors affecting heave, such as in situ stress, floor characteristics, and mine geometry, are described. Floor-displacement monitoring and data analysis methods are outlined. Finally, floor heave remediation is discussed. The remedial techniques are divided into four categories: mine maintenance, supplemental support, mine structure, and techniques for multiple-seam operations. Other subjects covered in the report include laboratory and in-place testing of floor rocks, U.S. and international case studies, effects of mine layout, determination of excess horizontal pressure, and types of heave failure. The emphasis of this report is on practical considerations; theoretical discussions are kept to a minimum.

Jan 1, 1992

By Meliton M. Garcia

The volume of gases produced in major and trace amounts following the detonation of two water gel and two emulsion explosives in a mine were determined. The volume .of the major gases (CO, CO2, NO, and NO2) was measured immediately following detonation, during the mucking operation, and following the removal of the muck. Tests to identify and quantify the gases produced in trace amounts were performed following the detonation only. The volume of each major gas per pound of explosive (ft /lb) ;ranged as follows: CO, 0.0424-0.3231; CO , 0.6819-1.5632; NO, 0.0129-0.1320; and NO2, 0.0019-0.1111.. An approximate average of 95% of the gases produced was found in the test chamber immediately following the detonation, while less that 2% was found in the chamber following removal of the muck. Benzene was the most significant compound found to occur in trace amounts. Scaling tests performed with a water gel and an emulsion explosive suggest that the volume of the gases per unit mass of explosive detonated diminishes as the amount of explosive per blast increases.

Jan 1, 1986

By C. Özgen Karacan

In longwall development mining of coal seams, planning, optimizing and providing adequate ventilation are very important steps to eliminate the accumulation of explosive methane-air mixtures in the working environment. Mine operators usually try to supply maximum ventilation air based on the capacity of the system and the predicted need underground. This approach is neither economical nor safer as ventilation capacity may decrease in time depending on various mining and coalbed parameters. Thus, it is important to develop better engineered approaches to optimize mine ventilation effectiveness and, therefore, to ensure a safer work environment. This study presents an approach using coalbed methane reservoir modeling and an artificial neural network (ANN) design for prediction and optimization of methane inflows and ventilation air requirements to maintain methane concentrations below statutory limits. A coalbed reservoir model of a three-entry development section, which is typical of Pittsburgh Coalbed mines in the Southwestern Pennsylvania section of Northern Appalachian Basin, was developed taking into account the presence and absence of shielding boreholes around the entries against methane inflow. In the model, grids were dynamically controlled to simulate the advance of mining for parametric simulations. Development and application of artificial neural networks as an optimization tool for ventilation requirements are introduced. Model predictions are used to develop, train, and test artificial neural networks to optimize ventilation requirements. The sensitivity and applications of proposed networks for predicting simulator data are presented and discussed. Results show that reservoir simulations and integrated ANN models can be practical and powerful tools for predicting methane emissions and optimization of ventilation air requirements.

By R. H. Grau, S. B. Robertson, F. Garcia, A. C. Smith, T. P. Mucho

Researchers working for the National Institute for Occupational Safety and Health (NIOSH) at the Pittsburgh Research Laboratory are developing ways to protect the health of miners. Part of that effort is devoted to improving the air quality in underground stone mines by developing ventilation techniques that can be used in these types of operations. The air quality in these large opening nonmetal mines can be significantly improved by using diesel particulate matter (DPM) controls along with sufficient ventilation quantities to remove contaminants. Practical methods of ventilating these underground stone mines can be accomplished by using mine layouts that course and separate ventilation air through the use of stoppings. The design, construction, and maintenance of effective stoppings in large openings have been a real challenge to mine operators. Several different types of stoppings have and can be used for this application. The choice of stopping design, material used, and construction techniques should be dependent upon a number of factors such as the intended life and effectiveness desired.

By Ray E. Harris

Introduction A resource of more than 122 Gt (134 billion st) of minable trona and mixed trona and halite underlies an area of about 3400 km2 (1300 sq miles) west of Green River, WY (Culbertson, in preparation) (Fig. 1). In 1982, the total domestic consumption of soda ash (refined trona) was 6 Mt (6.7 million st) (Kostick, 1983). About 90% of this came from Wyoming trona. This enormous deposit occurs in the Wilkins Peak Member of the Green River Formation that is of Eocene age. This formation is derived from sediments deposited in a large lake named Gosiute. Lake Gosiute occupied the Green River Basin in southwestern Wyoming some 38 to 54 million years ago. The Wilkins Peak Member represents a restricted, evaporite-rich cycle of deposition when the trona deposits were formed. A total of 42 trona beds are known. Of these, 25 are of sufficient thickness and extent to be considered minable (Culbertson, in preparation). The production of sodium compounds from the trona deposits in the Wilkins Peak Member began in 1896 when wells were drilled within the present boundaries of the town of Green River. The purpose of the drilling was for extraction of sodium carbonate brines. Sodium carbonate (sal soda) was removed from these brines at a plant in Green River. Bedded trona was discovered in 1938 in a core from an oil well drilled south of Westvaco. In 1947, the underground mining of trona began. Production has continued from 1948 to date. Currently, five companies are mining trona and producing soda ash from the Wilkins Peak Member in Wyoming. Additionally, Allied Chemical Co. mines and processes trona for Church and Dwight's sodium bicarbonate (baking soda) operation in Green River. Competition in the soda ash industry depends primarily on the efficiency of mining and refining, allowing for lower-cost production. Newer plants and mine designs should increase efficiency. Solution mining holds promise as an even lower-cost method of mining. Employment in the soda ash industry is declining since the newer mining and refining methods are less labor intensive. Declines in employment, however, may be offset as production increases. Due to the large resource, the availability of minable trona should not be a problem for perhaps hundreds of years. Geology of Wyoming trona deposits Forty-two beds of trona or mixed trona and halite occur in the

Jan 10, 1985

By Charles Findlay

As one of its projects for degasification of major panels of coal prior to mining within them, the Bureau of Mines conducted methane emission studies during development of a set of three headings 1,800 feet in a major coal panel (2,700 by 3,500 feet) which had been completely isolated by sets of main headings for 12 months in the Federal No. 2 mine (Pittsburgh coalbed) in northern West Virginia. Similar emission studies were conducted in the development of two sets of main headings in virgin coal areas nearby. Comparing the two sets of data indicated that the isolated coal panel had been degasified by approximately 70 percent.

Jan 1, 1973

By Samuel Canchaya

Los paquetes medianos y grandes de software a minería contienen en sus módulos de estimación de reservas alguna forma de análisis variográfico geoestadístico. En esa perspectiva, el presente trabajo señala la optimización de métodos tradicionales utilizados en dicha estimación a través de los conceptos y parámetros de la caracterización variográfica y estadística psra así minimizar las limitaciones de los métodos tradicionales.

May 25, 1998

By André van Wageningen

Since the beginning of this century Boliden Mineral and Atlas Copco have worked together in stages on improving the accuracy and quality of drilling. Navigation of the drill rigs with IREDES has been in use in the Boliden mines for several years. Recently the capability of the system has extended with map navigation to more accurately follow the ore in cut&fill mines. The system allows for changes on the individual round level to follow the ore without changing the whole design for the heading. Those changes are done in a CAD-system and remove the need for face markings and will allow for even better accuracy in both height and wall position. All the information between the CAD-system and the drill rigs is exchanged using the IREDES standard. This paper describes the workflow and the use of the IREDES standard.

Oct 1, 2009

By S. R. Amos, N. O. Lotter, A. L. Hannaford, J. F. Oliveira, D. W. Broughton

"Ivanplats Ltd appointed Xstrata Process Support to perform the flowsheeting development work for their hypogene and supergene geomet units of the Kamoa Copper deposit, located in the Democratic Republic of the Congo. Through systematic flowsheet development using modern Process Mineralogy, the optimised milestone flowsheet delivered a saleable concentrate grade of 32.8% Cu at 85.4% recovery with hypogene ore, and a saleable concentrate grade of 45.1% Cu at a recovery of 83.4% for supergene ore. The significant value of this development is that a single flowsheet will treat both hypogene and supergene ores and produce saleable concentrates. Further work to advance the flowsheet performance has been identified for investigation in the near future.INTRODUCTIONLocation and Description of the Kamoa DepositThe Kamoa copper resource is located some 40 km west of the city of Kolwezi, in the south west of the Katanga Province of the Democratic Republic of the Congo, in the region of Central Africa. Drilling at Kamoa in 2008-2009 had discovered laterally continuous, sediment-hosted, high-grade stratiform copper mineralisation in a newly discovered copper district that forms a previously unrecognised western extension of the famous Central African Copperbelt – which hosts such world-class deposits as Kolwezi, Tenke-Fungurume, Konkola and Nchanga. This discovery showed that the western end of the Copperbelt in the Congo does not terminate at Kolwezi (Friedland & Broughton, 2009). The resource contains hypogene and supergene geomet units with a transitional zone located inbetween the (upper) supergene and the (lower) hypogene. In the hypogene unit, the major copper sulphides are bornite, chalcopyrite and chalcocite, whilst in the supergene, the sequence is led by chalcocite, then bornite, and finally chalcopyrite. Covellite is present in both units as a minor copper sulphide. Both geomet units will be mined and treated in one concentrator, either as blends or as campaigns."

Jan 1, 2013

Protect mine rescuers from heat-induced stress that drastically cuts their endurance and saps their strength. Approach To prevent exhaustion caused by thermal stress, a rescuer can wear a liquid-cooled hood and vest which absorbs heat, thereby reducing the heat-induced strain on the rescuer's heart and circulatory system. How It Works Liquid coolant is continuously circulated through a self-contained system in which the coolant is chilled by a heat sink on the wearer's belt. The coolant, which is a mixture of alcohol and water, is pumped from the heat sink to bladders inside the hood and vest where it absorbs body heat. After absorbing heat In the hood and vest areas, the coolant returns to the heat sink where it is rechilled by passing through a tube coiled around a steel can containing a block of ice. To adjust the temperature of coolant leaving the heat sink unit, a valve can be operated by the wearer, causing part of the flow to bypass the coil. A small pump and a rechargeable battery are also part of the assembly.

Jan 1, 1979

By Frederick Laist

AFTER a series of experiments covering a period of about three years, ending from the spring of 19iJ.2 to the spring of 1915, a 2,000-ton leaching plant for the treatment of the accumulated copper concentrator tailing was built and put into operation. During the experimental period, the first step was that of laboratory experiments or beaker leaches. The results on this small scale were so satisfactory that a small operating plant, capable of handling 5 tons of roasted tailing per day, was installed. Again, the results proved satisfactory and an 80­ton plant was built and operated continuously from August until February, 1913. In this plant, full-sized roasting and leaching units were

Jan 8, 1916

The Performance of Benzyl Arsonic Acid as a Collector in the Flotation of Wolframite and Cassiterite Slime

Sep 13, 2010

By F. S. Karn

Conditions necessary to obtain optimum yield of useful products when coal is rapidly heated to extreme temperatures by laser irradiation were determined by the Bureau of Mines. Product distribution and yield were investigated as functions of several variables. Low-rank coals with high-volatile matter gave highest total gas yields. Medium-rank coals gave the highest yields of H2 and CA and low-rank coals gave highest yields of CO and C02. Macerals gave gases of approximately the same composition, but the total gas yield increased in the order fusinite, micrinite, vitrinite, and exinite. Total gas and C2H2 yields varied inversely with particle size. The addition of nominally inert gases such as Ar, He, N2 increased yields of H2, C2H2, and total gas. Metals such as nickel and platinum had little influence on the rate of coal decomposition. Total gas yield increased with total energy of irradiation, and the ratio of C2H2-CH4 increased with concentration of energy. A study was also made of the irradiation temperature, and a material balance was calculated.

Jan 1, 1970

By T. T. Campbell

This investigation was undertaken by the Bureau of Mines to determine if high-purity ductile molybdenum of uniform quality can be prepared by bomb reduction techniques. Molybdenum trioxide (Mo03) and mixtures of molybdenum dioxide (Mo02) and trioxide were reduced by magnesium in closed steel bomb reactors. Very high pressures in excess of 5,000 p.s.i. developed during magnesium reductions of Mo03. The addition of calcium oxide to the bomb charges caused a significant reduction in pressure. Reaction efficiencies higher than 95 percent were obtained during magnesium reductions of either Mo03 or mixtures of Mo02 and Mo03, but high pressures were encountered when the charges contained from 30 to 60 percent Mo02. Reaction efficiencies were usually low (less than 80 percent) when the bomb charges contained more than 40 percent Mo02. The charges with the best composition considering operating pressure, yield, and purity contained from 10 to 30 percent Mo02. The addition of small amounts of carbon to the reaction charges was helpful because some deoxidation occurred during the reduction and also during subsequent arc-melting of the regulus metal. The purity of the bomb-reduced, arc-cast molybdenum metal ranged from 99.2 to 99.8 percent and in some instances the metal contained as little as 5 parts per million oxygen.

Jan 1, 1962

By Donald W. Breck

Zeolites were first recognized as a new group of minerals by Cronstedt with the discovery of stilbite in 1756. The word zeolite was coined from the two Greek words meaning "to boil" and "a stone" because of the loss of water when heated in the mineralogist's blow pipe. (1) In 1845 it was discovered that certain soils have the power of retaining ammonium Salts. (2) These were the first ion exchange experiments. Later it was discovered that it was the hydrated silicates in the soil that produced this phenomenon and several years later a paper was published dealing with the action of dilute salt solutions on silicates which showed that this base exchange principal, which we now call cation exchange, is reversible. The quantitative cation exchange behavior of zeolite minerals, such as chabazite, was studied. As a result any aluminosilicate which exhibited the property of ion exchange was referred to as a "zeolite;" even today the term has been applied to clay minerals as well as synthetic organic ion exchange resins.

Jan 1, 1973

By Wellington Pereira Inácio

This work investigated the toughness behavior of polyester matrix composites reinforced with up to 30% in volume of long, continuous and aligned sisal fibers by means of Charpy impact tests. It was found that the addition of sisal fibers results in a marked increase in the absorbed impact energy of the composites. Macroscopic observation of the post-impact specimens and SEM fracture analysis showed that longitudinal rupture through the sisal fiber interface with the polyester matrix is the main mechanism for the remarkable toughness of these composites.

Jan 1, 2010

By Marco Taipe

Uno de los mayores costos del proceso minero es el de perforación, en tanto emplea aire comprimido. Por tal motivo, la industria minera busca diferentes alternativas para reducir los costos del aire comprimido o eventualmente a través del uso del sistema electro-neumático. Este sistema es de fácil instalación y mantenimiento puesto que se basa en electricidad y agua, reduciendo costos y a su vez mejorando las condiciones de trabajo a través de la versatilidad del presente sistema.

Sep 12, 2011

By K. M. Stone, N. J. G. Masson, A. C. Woollett

The Jabali zinc deposit, in Yemen, contains at least 9.4 Mt at a grade of 10.7% zinc, 2.2% lead and 77g/t silver. The zinc occurs as smithsonite with minor hydrozincite. The Jabali ore does not produce a zinc concentrate of sufficient grade to be acceptable to conventional smelter/refineries, and it has been necessary to formulate a less conventional development plan. This involves the construction of a mine and concentrator at Jabali and a metal production facility using a new flowsheet designed specifically for the treatment of oxide material, at Yanbu, in Saudi Arabia. In order to give the facility the necessary economies of scale, the Jabali concentrate will be supplemented by feed from other deposits, this may be either oxide or sulphide material. The paper outlines the geology and proposed mining and treatment operations at Jabali, the flowsheet for Yanbu and presents preliminary costs for both operations

Jan 1, 2002