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By R. J. Sweigard

One of the foremost problems in reclaiming prime farmland is compaction of the subsoil which is caused by the reclamation equipment. Wheel tractor-scrapers are most commonly used to replace subsoil and have been blamed for the majority of the compaction problems. Two methods of alleviating this problem that are presently being considered are mechanical subsoil loosening machines and truck- shovel combinations for subsoil handling. A field study was conducted in which dry bulk density measurements were taken in an effort to determine the effectiveness of truck-shovel combinations and subsoil loosening equipment in reducing bulk density in comparison to typical scraper replacement.

Jan 1, 1987

By Louis A. Panek

Research on roof bolting has developed significant information with respect to the functions that can be performed by properly installed bolts and the methods that can be used to ensure that effective installation has been achieved. The present paper brings together results that are pertinent to the design of a bolting system for reinforcing horizontally stratified mine roof with vertical bolts. The design approach is based on the use of bolts to decrease the maximum bending stress within an arbitrary sequence of roof strata (such as shown by figure 1) in which the only loads are the weights of the individual beds. The use of rock bolts to achieve other objectives, such as to stabilize a fractured rock mass on the periphery of a mine opening (3), is excluded from consideration herein.

Jan 1, 1964

By A. D. S. Gillies

The effectiveness of coal mine face ventilation and the ability of air flow to maintain satisfactory methane and respirable dust levels in the working face area has been studied through the use of scale modeling techniques and underground testing procedures. In particular, consideration has been given to examination of the effects of operation of a high air flow machine mounted dust scrubber unit on face air patterns. Results obtained through a cooperative study with the Peabody Coal Company demonstrate that new mining cycles can be considered which increase production efficiency while maintaining satisfactory ventilation conditions.

Jan 1, 1982

By C. D. Wittreich

The University of Idaho, Department of Metallurgical and Mining Engineering, through the Generic Mineral Technology Center, has been engaged in mine design research at the Lucky Friday Mine, Mullan, Idaho. The purpose of the research is to develop and implement the longwall underhand cut-and-fill mining method for conditions at the Mine. The longwall underhand cut-and-fill mining method involves backfilling mined stopes with a compacted tailings-cement mix. After the backfill has been allowed to cure, mining is resumed from underneath. Horizontal stresses in the Lucky Friday Mine are exceptionally high and rock bursts are a common problem. Beus and Chan (1980) have reported a 2:1 horizontal to vertical stress ratio at the mine with a 65-MPa (9,500-psi) maximum horizontal stress at the 1,295-m (4,250-ft) level. Using this mining method under these stress conditions, it is desirable to have a backfill material that has sufficient strength to safely carry the high horizontal wall loads while minimizing external steel supports.

Jan 1, 1987

By G. T. Lineberry

Reduced clearance is one of the most important characteristics of encumbered space in underground coal mining. Another key variable is the maximum velocity at which a piece of mobile mining equipment can operate in this limited space. Typical velocity- clearance curves for different mine transportation systems are developed and characterized. Applications of the relationships are examined, emphasizing their significance in the design and control of mine materials handling systems.

Jan 1, 1983

By B. Waquet

The genesis of a hydrothermal subsea mound, by chimney debris heaping and mineralizing fluid circulating upward, induces a vertical maturation gradient. Connected porosity is easy to measure and, after mineralogical evidence, can be use as a maturation index. Thus, to understand how a rock property evaluates with maturation, it is possible to plot it against connected porosity. Results are that uniaxial compressive strength, Young's modulus, and in a lesser certitude tensile strength, abrasivity and hardness, increase very weakly with maturation until a maturation threshold (equivalent to a connected porosity equal to 0.2), and rocket to much higher values after it.

Jan 1, 2011

By Yoginder P. Chugh

The term "fatigue" in mechanics, is used to refer to reduction in the strength of a material subjected to fluctuating or alternating stresses. Stresses that vary with time are called fluctuating stresses and if during fluctuation the stresses also change sign, they are called alternating stresses. In the field of rock mechanics, the term fatigue (static fatigue) has often been misused to refer to failure of geologic materials in time domain under constant load. To avoid confusion, we use the ten cyclic fatigue here to refer to failure of rock under alternating or fluctuating stresses. Fatigue in metals has been studied for over 100 years. Fatigue properties of geologic materials have, however, received little attention in the past. This is probably because until recently very little was known in regard to the behavior of geologic materials even under static loading. Secondly, suitable equipment for conducting cyclic fatigue experiments was not available until quite recently. A few cyclic fatigue studies have been undertaken on geologic materials to relate it to percussive or rotary drilling mechanisms (e. g. Grover et a11*; Burdine2). The results of these studies were inconclusive due to limited effort. Cyclic fatigue in concrete has been studied more extensively than geologic materials (e.g. Nordby3, Gray et al 4 and Bennett et a15) and mechanisms of fatigue in concrete are better understood than in geologic materials.

Jan 1, 1975

By Stuart Brashear, J. W. Reil

The manuscript of this paper was not available for publication when the Proceedings went to press. Should the authors elect, they may distribute copies at the time of the Symposium.

Jan 1, 1986

By S. Zaharia

The authors present the state-of-the-art regarding natural and anthropic hazards on the stability of the saliferous Costiui basin. The factors that may potentially result in sliding, piping and collapse, are emphasized, given the existence of a large number of old salt mines. Also, a geotechnical risk map of this hydrosalt complex in Romania is presented.

Jan 1, 2008

By K. M. O’Connor

Time Domain Reflectometry (TDR) is a pulse testing technique developed by the telecommunications and power industry for use in locating breaks in cables. Variations of this principle have been utilized in applications pertinent to closure and reclamation of coal operations. This paper focuses on applications of TDR technology in the mining industry including monitoring of slope movement, abandoned mine subsidence, ground water levels and subsurface LNAPLs, landfill cover performance, and consolidation of mine tailings. TDR technology has been particularly effective for remote automated monitoring, and alarm systems have been implemented for monitoring subsidence.

Jan 1, 2003

By J. S. Aronofsky

The areas are identified where the techniques of operations research have been applied in the petroleum industry. Particular emphasis is given to the linear program models that have been used for solving management problems. Of the entire gamut of applications for linear programming, attention is focused on the models that represent underground reservoirs. Such models could be used to help schedule drilling rig operations and to schedule oil production. A framework is established for placing the model for underground reservoirs in the proper perspective along with the models which represent other facets of the oil business. One of the remarkable phenomena of this century is the rapid growth in the size and' complexity of human organizations. The mere size of modern business means that administrative decisions can affect vast quantities of capital and large number of people. Mistakes can be tremendously costly, and a single wrong decision can require years for rectification. Moreover, the pace of modern business is such that decisions are required more rapidly than ever before; the mere postponement of action can give a decided advantage to a competitor. It is not surprising that the increase in difficulty of decision making has been followed by efforts to put this activity on a more objective basis. The growing science of operations research, which relies heavily on the methods that have proved so successful in the physical sciences, is one aspect of these efforts.

Jan 1, 1962

By B. J. Scheiner

The Federal Bureau of Mines has developed a chlorine-oxygen leaching technique for the recovery of metal values from lead-zinc sulfide concentrates. Lead, zinc, copper, cadmium, and silver extractions are in the 95- to 99.9-percent range. During leaching, the zinc, copper, cadmium, and silver are solubilized as metal chlorides, and lead is converted to insoluble lead sulfate. The iron contained in the concentrate is converted to insoluble iron oxide, and a majority of the sulfide is converted to elemental sulfur Minor metals such as copper, cadmium, and silver are recovered by precipitation with zinc dust. Zinc is then recovered from the purified zinc chloride solution by evaporation to dryness; the lead is recovered from the leach residue by brine leaching and crystallization to produce lead chloride. Recovery of zinc and lead metals by fused-salt electrolysis of the chlorides is being studied separately.

Jan 1, 1975

By J. K. Conibear

Since the 1948 introduction of hydraulic fill at the Sudbury Ontario Mines of the International Nickel Company of Canada, 32,000,000 tons of water-borne sandfill and 420,000 tons of portland cement addition have been placed in underground workings. Fill method mining, currently conducted at six of the ten operating mines, accounts for 28 percent of the total mines underground production. Both classified mill tailings and screened alluvial pit sand are used as fill for cut-and-fill primary mining, undercut-and-fill pillar recovery, and backfilling of blasthole and shrinkage stopes. Cemented fill, consisting of a lean mixture of portland cement, is used in areas where a stabilized fill is required to reduce dilution and aid in the recovery of adjacent pillar ore.

Jan 1, 1970

By Charles E. Weaver

A core from the La Camelia attapulgite mine in north Florida was studied in detail to determine the detailed vertical variability and the relations of the various parameters. The structural, textural, mineralogical and chemical data indicate there are two major depositional cycles represented within the minable interval. The sediments deposited during the two cycle differ in detail but in general are similar. The environments of deposition grade from shallow marine to lagoonal to tidal flat to marsh. The sedimentary structure (lamination, burrows, pebble conglomerate), mineralogy (attapulgite, montmorillonite, sepiolite, dolomite, calcite) chemistry (Al, Mg, Fe) are closely related to each other and their nature is determined by the depositional environments. Most of the clay minerals and carbonate minerals are authigenic and are therefore particularly sensitive to environmental differences. The variability and environmental features seen in this core are characteristic of the sediments in the general attapulgite mining area. A detailed understanding of the relationships discussed should be of value in prospecting, mining and processing.

Jan 1, 1972

By A. Wallace Mitchell

Barite deposits in Nevada occur as bedded and vein-types along a north-northeastern -trending zone which parallels the Antler orogenic belt The bedded deposits of Nevada are the most significant economically. They are presently supplying eighty-five percent of the domestic barite production which is used primarily as a weighting agent in the petroleum drilling industry. The ore bodies are controlled both structurally and stratigraphically, occurring along regional and local structural breaks in siliceous eugeosynclinal rocks of mid-Paleozoic age. Evidence for origin of the barite includes sedimentary and hydrothermal features indicating that localization probably took place along fractures in the seafloor.

Jan 1, 1980

By Fulvio V. Fonseca

The Trombetas bauxite deposits were discovered by ALLAN, as from the original work of the geologists Drs. E. E. GREIG and 3.A. STAARGAARD on the axis of the Amazon river, between Manaus and Santarem - (see fig. 1). With research licences obtained in 1965 by the SANTA RITA BAUXITA - a subsidiary of ALAN a group of Brazilian geologists, under the supervision of IGOR MOUSASTICOUSHVILLY, begins researches on the areas of Parintins, Juruti and Mathias with unsatisfactory results. In 1966, photographs obtained from the US Air Force and the Brazilian Oil Company PETROBRAS -, covering an Amazon region between Parintins, Santarem and north of Trombetas river, permitted the identification of a great number of plateaux between the Nhamunda and the Trombetas rivers. Based on this information, a research group has worked intensively from 1966 to 1967 allowing the discovery of the trihydrated bauxite in a quite large area. After five years of intense work and analysis of approximately 56.000 samples, near 500 million of tonnes of bauxite are evaluated on the several plateaux of the, area, thus insuring the commercial exploration of these deposits. Such discovery places Brazil among the detainers of the main bauxite stocks of the world and as a potential exporter.

Jan 1, 1980

By S. M. Hsiung

This paper presents the results of an extensive study concerning a series of roof falls in a room-and-pillar coal mine located in West Virginia. Three dimensional finite element modeling was employed to identify the possible causes for the roof falls. The effectiveness of possible roof control measures for alleviating or eliminating the adverse roof conditions is analyzed, discussed, and compared. The best mining alternatives are recommended. It has been found that large overburden depth and typical roof geology are the major reasons for the roof falls. Angle bolting may not solve the problem encountered in the mine studied. Changing the mine layout currently used in the mine appears to be the best alternative. The recommended pillar size and entry width which will eliminate the problem completely are 90 ft. x 90 ft. and 14 it., respectively.

Jan 1, 1985

By L. G. Martin

Early mining at Manhattan demonstrated that blasthole assays alone were insufficient to control the disposition of material. A program was began using controlled blasting, intense sampling and panning of crushed samples, fire assay checks, and geologic inspections to sort material in the pits. Statistical data confirms that the method provides effective control at minimal cost. This cost is easily offset by additional tonnage found in areas considered to be waste.

Jan 1, 1980

The main goal of this paper is to present readers with recommendations for choosing coaxial cables appropriate for mining applications of Time Domain Ref 1 ectometry (TDR) to monitor rock mass movements. Prior to discussing the recommendations, mining applications are illustrated with examples and the operating principle of TDR is discussed briefly. Items that affect the result of the monitoring system performance include the coaxial cable selected, the grouting material used, and the installation procedure.

Jan 1, 1986

By Carlos Viramontes Aldana

Mining in Mexico is one of its post traditional activities, whose influence in the development of important cities and communications has been decisive. Precious metals and, to some extent, copper and tin were known and used before the Colonial period, but from the sixteenth century to tie end of the nineteenth century, mining and metallurgical industries were concentrated in the precious metals, mainly silver. This silver was exported to Spain and other countries under the Spanish. Rule, Mexican peso was known world wide since the end of the sixteenth century and Mexico ranked as the first silver producer since the eighteenth century.

Jan 1, 1985