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By S. P. Singh

Rockburst is a sudden manifestation of the release of elastic strain energy stored in the rock. Therefore the tendency of the rock to burst should depend upon its ability to accumulate elastic strain energy. The use of Burst Proneness Index as a simple and reliable indicator to recognize the burst prone situations in the mines has been advocated in this study. The Burst Proneness Index exhibited a strong dependence upon the brittleness, compressional and shear wave velocities and the point load strength index. It was also observed that the Burst Proneness Index increases with the increase in the strain energy per unit volume, c ressive strength and the modulus of rigidity of the rocks. In addition, important causes and the measures to alleviate rockbursts have been outlined in this paper.

Jan 1, 1986

Interest in mineral sand mining in the south west corner of Western Australia began in the late 1940's and significant production commenced in 1956. Early land use conflicts arose because of conservation implications (Ludlow tuart forest), expanded to include post-mining rehabilitation requirements (the Wonnerup mine near Busselton) and today include some agricultural/mining disputes. These latter conflicts are largely caused by the need for mining companies to secure longer-term reserves. To date, deposits containing mineral valued at A$440 million have been sterilized and are unlikely to become available in the future. There is additional pressure being placed on presently available reserves and a pessimistic picture could be drawn, whereby the southwest mineral sands industry ceases to exist by the year 2010. However, sensible land use planning, the support of policticians and the community, and responsible attitudes towards compensation and rehabilitation could, in combination, see the industry maintain significant mineral output until the middle of the 21st century. Examples of deposits sterilized by adverse land use will be given.

Jan 1, 1986

By J. Douglas Causey

In 1984, at the request of the Bureau of Land Management, the Bureau of Mines studied 9,600 acres of the 12,350-acre Antelope Creek Wilderness Study Area (MT-065-266) in order to evaluate its mineral resources. Within this report, these 9,600 acres are referred to as the study area. The Antelope Creek Wilderness Study Area, Phillips County, MT, adjoins the north end of the Charles M. Russell Wildlife Refuge. Considered part of the Missouri River Breaks, the area straddles the edge of a thrust fault zone that has deformed the Mesozoic strata in the west half of the area. Shale, siltstone, and sandstone of Cretaceous Age are exposed in the area. Coal beds averaging 3.0 ft thick occur in the Judith River Formation. About 0.20 million short tons of coal were mined from the Judith River Formation adjacent to the west boundary of the area; no production is known in the study area.

Jan 1, 1986

By L. Vandamme, J. H. Curran

A fully three-dimensional hydraulic fracture propagation model, based on the Displacement Discontinuity Technique, is briefly described. Using this model, it is shown that the geometry of a propagating fracture is dependent on several factors, among which the fluid pressure distribution within the fracture plays an important role. The containment of hydraulic fractures is found to be dependent on stress and toughness barriers in the formation. Containment is also observed to be more effective with a decrease of the viscosity, pressure or flow rate of the injected fluid. The three-dimensional layout of the fracture is shown to have a definite influence on the width and pressure distributions within the fracture. The examples considered indicate the need for fully three-dimensional models, as complements to the commonly used two-dimensional and pseudo-three-dimensional models.

Jan 1, 1986

By Dermot M. Winters, Brent T. Wahlquist, C. Y. Chen

The enactment of the Surface Mining Control and Reclamation Act (SMCRA) in August 1977 addressed subsidence resulting from underground mines, in addition to creating the requirements for reclamation of surface coal mines. Subsidence control regulations pursuant to SMCRA were initially promulgated in March 1979. Several revisions have since been made. In addition, due to court challenges some regulations have been remanded and others are still on appeal. In the meantime the Secretary has agreed to initiate rulemaking on some issues. It is yet to be determined how the prohibition of certain areas from surface coal mining operations under Section 522(e) of the Act applies to subsidence. This presentation discusses the status of the regulations and issues related to or affecting the subsidence regulations.

Jan 1, 1986

Over the last thirty years production of heavy minerals from Australian deposits has dominated the world market. The main incentive has been to suoply the raw material for titanium dioxide based pigments. These ~ninerals include ilmenite, rutile, leticoxene and more recently, synthetic rutile. Inevitably the viabilit/ of developing placer type deposits has seen influenced by other heavy minerals present, such as zircon and monazite, but these have been of secondary importance. For most of the sixties and seventies, Australia supplied the 'najority of free world rutile and zircon, and a large proportion of the ilmenite. With the run-down of rutile- rich reserves in eastern Australia, the emphasis has s:iifted in several countries, including Australia, to fill }the gap with i l Wen i to and its derivatives, leucoxene, synthetic rutile and titanium rich slag. over the next 15 - 20 years, as high grade beach placers in Western Australia are mined out, less traditional sources for mineral sands products will be opened up. Low grade placers (particularly those dominated by ilmenite) will be reassessed in Australia, U.S.A., Africa and Asia, and exploration will shift from beach and dune environment, to heavy mineral concentrations in alluvials, lake deposits and continental shelf deposits. At the same time, production of anatase and bastnaesite will be expanded, as required, from the huge resources contained in carbonatites in 3razil, U.S.A. and China.

Jan 1, 1986

A shift in the present day oil exploration scenario from West Coast can be foreseen keeping in mind peak of exploration in Cambay Basin and fast pace of development in Bombay High and its associated fields by the end of this century. Shifts in exploration from structural traps to stratigraphic traps, techno- logical development to drill in deep waters, improving economic situation for oil ventures and proven oil and gas potential of East Coast basins suggest that Indian oil explorat- ion scene will be at its peak along east coast during early 21st century. Hydrocarbon shows in Poonch and Jawalamukhi in Punjab Basin, improvements in drilling to greater depths, better seismic data aquisition, good source rock potential of Subathus and its equivalents and large geologi- cally mapped structures will reopen new avenues for explorationists. Not much exploration effort has been put up so far in Ganga Basin. Keeping in mind size of the basin, sedimentary thickness involved, presence of algal matter deposited in shallow marine environment & higher hydrocarbon indications warrant active exploration. Gondwanas in India having such a large sedimentary area can not be ignored keeping in view generation and production from the non marine sediments of Kenya, Chad, Sudan, Gadon and China. Gondwanas become all the more important in view of gas production from their equivalents-Karoos in Ethiopia and South Africa. In all, above mentioned changes can be predicted in Indian oil exploration scenario during 21st century.

Jan 1, 1986

By W. E. Horst

Historically, research organizations have made significant contributions to the development and commercialization of new chemical products for the mining industry and examples of commercial results are cited With the recent demise of research organizations within the mining industry and dynamic changes in the industry, the supporting role of R&D groups has become limited or non-existent. Cat- reduction requirements and new raw-material sources offer future opportunities for R&D organizations to continue their effective participation in the commerical development of new chemical products. Potential areas of interest for future process applications are reviewed.

Jan 1, 1986

By J. S. Hu

FTIR spectroscopy has been used for the characterization of adsorbed oleate at the fluorite surface. It has been found that modest changes in the adsorption density at high temperature and high oxygen potential do not provide a satisfactory explanation for the significant increase in the hydrophobic character of the system under similar conditions. Rather, FTIR spectroscopic measurements suggest that chemical interaction between adsorbed oleyl groups occurs at high temperature and/or oxygen potential and accounts for the increased hydrophobicity. Specifically, the intensity of the =CH bond of the adsorbed oleate diminishes at high temperature and/or high oxygen potential. Such a phenomenon was not observed in control tests with the calcium oleate soap. For extensive reaction at the fluorite surface, the presence of a new surface species has been identified. These results indicate that the fluorite surface catalyzes an oxidation and/or polymerization reaction between adsorbed oleyl groups which results in a more hydrophobic structure at the fluorite surface.

Jan 1, 1986

By Y. Nan

A new computer simulation model for the analysis of underground coal mine production systems in the Peoples Republic of China is presented. As a case study the model was used to analyse the railway system of an existing underground coal mine. Some results of this first application are given in this paper and some conclusions of common interest for underground rail haulage systems are discussed.

Jan 1, 1986

By D. Malhotra, K. Purdy, G. Ramadorai

INTRODUCTION Today, flotation is clearly the dominant mineral concentration method. Since it is a relatively selective process, it is used for almost all sulfide minerals. A recent U. S. Bureau of Mines study indicated that approximately 225 million metric tons of sulfide ore was processed in 67 plants in the United States in 1980 (USBM Staff, 1981). There were over 100 plants processing copper ores in the world (Bassarear, 1985). Sulfide ores containing lead, zinc, copper, molybdenum, precious metals, cobalt, nickel, and iron are generally separated and concentrated by flotation. This chapter briefly reviews the plant practice related to the recovery of the above-mentioned sulfide minerals with emphasis on chemical reagents used for the production of marketable-grade products. PROCESSING OF SULFIDE ORES It is beyond the scope of this chapter to review the milling data for operating plants which have been extensively covered in literature (Tveter and McQuiston, 1962; Rausch and Mariacher, 1970; Weiss, 1985; Crozier, 1979). However, the following generalizations can be made regarding the processing of sulfide ores: 1. The primary grind is targeted to produce as coarse a product as necessary to provide an economic degree of liberation. 2. The concentration process, generally flotation, is designed to produce a concentrate consisting predominantly of valuable minerals and a middling fraction which may require further grinding to produce an optimum release of minerals. 3. The chemical reagent suite (collectors, frothers, etc.) for the separation of sulfide minerals from gangue minerals is generally complex. Total reagents used in the flotation process can be as high as six to eight, as is the case for lead and molybdenite separation from complex sulfide ores. 4. Chemical reagents are generally expensive because of the high selectivity for sulfide minerals. The process flowsheet is dependent on several factors, including ore grade and mineralogical composition. Generic process flowsheets for processing different sulfide ores have been developed for discussion in this chapter. However, there appears to be a consistent relationship between the reagent combination choice and the mineralogical composition of the ore (Tveter and McQuiston, 1962). These are covered in detail in the following sections. LEAD AND ZINC Galena (PbS) and sphalerite (ZnS), which commonly occur together, are the only minerals of lead and zinc, respectively, in most primary deposits. Feed ore grades are typically 1 to 5 percent Pb and 1 to 10 percent Zn. Very often economic quantities of copper and precious metals, silver and gold, also occur with these base metals.

Jan 1, 1986

The Australian Mineral Industry has to compete on world markets, so its mineral research has to be aware of overseas developments, it must be of world class, and it must utilise as many ideas as possible in order to solve those problems that uniquely affect Australian minerals processing. North American mineral and resource research may be taken as a guide to world government, industrial, contract, and entrepreneurial research trends and ideas. A number of interesting findings are noted that may guide Australian developments and strategies for the future, in minerals research and exploitation.

Jan 1, 1986

Excessive use of computers in teaching, especially in self-learning programs, may destroy creativity and initiative. It is essential that engineers remain innovative to develop new technology. Safety legislation may have hindered the Development of mine managers. It may be necessary to develop two distinct streams of mining engineers. One should be biased towards human relations and safety, to 'be a certificated mine manager, and the other should be mathematically based as a high-technology mining engineer who would not necessarily qualify for a certificate of competency without a postgraduate course.

Jan 1, 1986

By K. K. Haramy, J. McDonnel

INTRODUCTION Primarily because of mining at greater depth, an increasing number of coal mines in the United States experience floor heave problems. In many instances, the floor heaves at a slow rate without causing health and safety related problems; only additional roadway maintenance and coal handling equipment are required. However, when rapid, massive heaving occurs, the safety of mine personnel in the vicinity is jeopardized. Extensive floor heave causes a redistribution of stress around the mine opening and can cause additional ground control problems. This paper presents an analysis of rapid floor heave in a deep western coal mine. The analysis is based on field measurements, laboratory data, and beam design theory. Factors affecting floor heave, such as mining-induced stress, mine opening size, entry orientation, mine geology, rock physical properties, and gas pressure, are considered. Examination of floor heave in the mine indicates that heaving is primarily caused by deformation of a soft floor member that is subjected to high mining-induced stress. Theoretical analysis of in situ floor stresses resulting from overburden loading indicates that floor failure will occur. The analysis is confirmed by visual observations of floor heave in the mine. Recommendations for mine layout and opening design to control rapid, massive floor heave under these conditions are also presented. MINE-FLOOR-FOUNDATION THEORY The floor stratum in a coal mine acts as a foundation to support coal pillars and artificial supports, thereby providing support to the mine roof. The overburden load, transferred through pillars and other supports, applies tremendous stress to the floor. Soil mechanics theories provide solutions for foundation design problems that apply to the mine floor. Based on foundation theory, vertical load on pillars causes high shear stress zones in the floor. If the floor is relatively weak, it may fail and dislocate upward into the mine opening. Strong roof strata that do not readily fail transmit most of the overburden load through pillars to the floor. Heaving may result, depending on the thickness and physical properties of the floor

Jan 1, 1986

By W. J. Miles

Oil based drilling fluids utilize a number of industrial mineral products to accomplish oil and gas drilling in several environments where water based drilling fluids are less effective or inappropriate. These industrial minerals include: organically modified bentonite, organically modified lignite, barite, hematite, mica, calcium chloride and other salts. A variety of organic products are also utilized in oil based drilling fluid formulations. Oil based drilling fluids are preferred in several drilling situations because: they can be used to drill through water sensitive formations; they produce holes that are very close to the drill bit gauge; they exhibit high temperature stability; they are more environmentally acceptable; they minimize producing formation damage; they provide faster drilling rates when used with new polycrystalline diamond drill bits; they minimize pipe sticking and lost rig time.

Jan 1, 1986

By J. W. Harshbarger, E. L. Montgomery

The region of metallic ore deposits in northern Chile, southern Peru, western Bolivia, and northwestern Argentina occurs in arid zones at altitudes as high as 6 km (19,700 ft). Because surface water supplies are meager, new mines require unexploited sources of water. Prolific ground water aquifers occur in salar basins in this region of the Andean Highlands. Exploration water wells have been constructed and aquifer characteristics have been tested in eight salar basins. Results indicate ground water quality is good. Aquifer transmissivity and storage computed from results of pumping tests indicate maximum capacities of more than 170 L/sec (2700 gpm) for individual production water wells. Results of investigations conducted by the authors demonstrate that ground water reservoirs in the Andean Highlands comprise a source of large quantities of water for the mineral industry.

Jan 1, 1986

The New Zealand Steel Ironsand Slurry Pipeline was successfully commissioned in February 1986. The project includes 18 km of high pressure, polyurethane lined buried pipe. McConnell Dowell Constructors Limited has developed a coupling which has allowed this pipeline to be fully welded. The design and development of the coupling and its application on this project is discussed.

Jan 1, 1986

By J. L. Yordan

An induction time apparatus has been constructed in the present work which has a sensitivity limit of 100-150 micro-seconds. The basic unit is similar to the one used by Eigeles and Volova (1960) and Trahar (1983), but it operates with a micro-computer and has a greater sensitivity. Using this apparatus, the flotation chemistry of the quartz-amine system has been studied. It has been found that at a given dodecylamminium hydrochloride concentration, the induction time is at a minimum at approximately pH 10.5. At this pH, the collector hydrolizes to form neutral amine and the flotation recovery reaches a maximumy,suggesting that iono-molecular species are the surface-active species responsible for flotation. This finding confirms the earlier conclusions obtained using the surface tension (Somasundaran, 1976; Finch and Smith, 1973) and contact angle (Smith, 1963) techniques. The induction time measurements have also been conducted as a function of particle size, collector concentration, indifferent electrolyte concentration and temperature. The results are compared with flotation data, and the activation energies for the bubble-particle adhesion have been calculated.

Jan 1, 1986

By R. E. Ray, J. W. Stevenson, J. A. Berry

Conventional concrete block plastered with a cementitious coating is the most common material used in the construction of permanent stoppings to direct airflow in underground mines in the US. All mines experience various degrees of strata convergence depending on depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting insignificant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overhead to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating a polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

Jan 1, 1986

By J. M. Pachter

Property sales and acquisition are prominent features of today's coal industry. Before selling or buying a site, a company must know the property's economic net worth. Any evaluation of economic net worth would be inadequate if determinations of a property's environmental liabilities and costs were omitted. Short-term and long-term costs can result from liabilities related to reclamation, water treatment, subsidence, and hazardous waste disposal. A structured, interdisciplinary approach can aid in the delineation, summation, and scheduling of these costs and liabilities.

Jan 1, 1986