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By Robert E. Miller

Mass blasting of open stopes and pillars is a normal operating practice at Isa Mine. Three main parameters are used to classify the types of mass blasts. These are type of explosive used, blasthole diameter and system of initiation. Both electric and non-electric initiating systems are currently employed. The advantages gained by large firings are many. More efficient utilization of manpower, due to the concentrated and continuous charging, is achieved. There is no requirement for men to re-enter areas where localised ground conditions may have deteriorated and exposure of ringfirers to stope voids is reduced.

Jan 1, 1980

By K. T. Dreher, J. A. Brierley, C. L. Brierley

Water from underground uranium mines located in the Ambrosia Lake district near Grants, New Mexico, U.S.A., is treated to reduce levels of uranium, selenium, radium and molybdenum. The treatment system consists of a series of ponds and an ion exchange plant. Bacterial and algal populations present in the pond system are considered agents which actively assist in removal of the pollutants present in the water. Pondbottom sediments maintain a reducing zone and a large population of sulfate-reducing bacteria of the genera [Desulfovibrio] and [Desulfotomaculum]. Uranium, molybdenum, and selenium accumulate in the pond sediment. Stimulation of the microbial sulfate-reducing activity resulted in a decrease of soluble concentrations of these elements in laboratory systems. Predominant components of the treatment ponds’ algal flora are the filamentous [Spirogyra] and benthic [Chara]. Laboratory study indicates that [Spirogyra] is more active than [Chara] in removal of uranium and molybdenum from solution. However field-collected algal samples of both of the genera contain uranium and molybdenum. Laboratory studies indicate that death and decay of the algae in association with pond sediment does not result in return of cellbound uranium and molybdenum to the water. The algae appear to act as bio-filters for accumulation of particulate pollutants and agents for adsorption and/or absorption of soluble pollutants.

Jan 1, 1980

By Öner Yücel, M. Zeki Dogan, A. Metin Ger

Technical and financial feasibility studies conducted at the Middle East Technical University, in Ankara, Turkey, have revealed that a 400 km long prospective slurry pipeline between Hasançelebi and Iskenderun could efficiently and economically transport iron concentrates, with a size of 55%-325 mesh and of amounts varying between 0.25 and 8.0 million tonslyear. Particularly for annual throughputs above 500,000 tons, favorable results have been obtained regarding the processing of the ore, the applicability, the transport cost, and the foreign ex- change currency savings.

Jan 1, 1980

By Jr. Moulton

Extractions of minerals from Searles Lake brines have taken place since 1873. Early operations were for borax and raw trona found on the surface, expanded after 1914 to include potash, salt cake, and soda ash. A new soda ash plant now in operation will double area production. The evaporite beds were formed by desiccation of Eastern Sierra runoff. The resulting series of brine-bearing salt beds supply the fluids necessary to feed the area chemical plants. Production methods include evaporation and crystallization for potash, borax, and salt cake; carbonation of brine to recover soda ash; and organic extraction of borax.

Jan 1, 1980

By Carl A. Holley

Agglomeration is very closely identified with the mining industry. Ores must be crushed finer and finer to separate minerals from gauge and the fine ore concentrates must be agglomerated so they can be handled for further processing. This paper reviews each type of agglomeration device and summarizes the areas of usage for each type of agglomerator.

Jan 1, 1980

By W. A. Steingraber

This paper discusses the application of deep well disposal techniques to the problem of disposing of large volumes of low level radioactive wastewaters generated by the in situ uranium mining industry in Seth Texas. Data is presented on wastewater composition and volumes, geologic and hydrologic parameters of the disposal reservoirs, tell construction techniques, well operation, well monitoring requirements, and critical factors in evaluating the Safety and environmental impact of a deep injection well system.

Jan 1, 1980

By Wm. Terry Siemer

Abstract. The value of industrial rocks and minerals produced in New Mexico in 1978 exceeded 227 million. 1e state ranked first in the nation in production of potash and perlite and was a leader in pumice production. Other commodities with sizable production in New Mexico include barite, caliche, clay, dimension stone, fluorspar, gypsum, humate, limestone, mica, salt, sand and gravel, scoria, and silica sand Non metallic resources are distributed throw out the state, but development and exploitation is concentrated in western and southeastern New Mexico. The value of industrial rocks and minerals within the state grew about 9 percent to more than $227 million in 1978. Continued growth, however, depends on continued demand, exploration, and development.

Jan 1, 1980

By R. Hemp

This paper describes work carried out to obtain a heat balance in the B3 shaft longwall stope at Blyvooruitzicht gold mine. Recordings were made of the temperature of the air and chilled water entering and leaving the section during three periods, August 1 September 1977, November 1 December 1977 and March 1978. These recordings, together with numerous other measurements were used to determine the rate at which heat was being removed from the section by the various fluids flowing through the section. The rate at which heat was entering the section was then calculated, by considering each source in turn. These two sets of figures made it possible to draw up a heat balance, and also obviously gave vital information on the magnitudes of the various heat sources and on the methods used to remove heat. In general reasonable heat balances were obtained, the errors being in the range -6 per cent to +22 per cent.

Jan 1, 1980

By M. Dayne Aldridge

A description is given of an experimental ventilation control system designed, built, and tested by WVU under United States Bureau of Mines sponsorship. A description is given of the control, system used and the mine-wide microcomputer-based ventilation monitoring system used with it. Test results of experiments conducted with this system at Eastern Associated Coal Corporation's Federal No. 2 underground coal mine are presented. In addition, a brief description is given of a new microprocessor based system presently being tested.

Jan 1, 1980

By Fritz F. Prugger

This paper considers some of the main aspects of underground mining in the flat, rich, but deep lying deposits of Saskatchewan. It briefly describes the pertinent geological features as they relate co mining and the practical de-stressing techniques used to allow productive extraction in the high stress environment present in many of the province's mines. Fining layouts, materials handling and the evolution of some of the world's largest mining equipment are examined.

Jan 1, 1980

By R. A. Frith

"Belts of Yellowknife Supergroup volcanic and sedimentary strata in the Slave Structural Province are separated by granitoid complexes. The strata and most intrusive rocks are 2.7 and 2.5 Ga old, but rocks around 3.1 Ga have been recognized in some of the complexes and are believed to represent a once-extensive sialic crust. Volcanics were erupted along rifts in this crust and the rifts became sites of crustal foundering and the development of troughs that filled with turbidites of volcanic and granitoid provenance. Present margins of the granitoid complexes may be close to the original margins of deposition of volcanics, with associated mineral deposits, and close to the thickest parts of basins of sedimentation.The Hackett River volcanic belt extends 100 kilometres between Mara River and Back River and is crudely S-shaped, with a northern sector surrounding a core of granitoid basement rocks, a northeasterly facin g central sector and a southerly facing southern sector. Up to 8 kilometres of andesitic volcanics with intercalated felsi c volcanic rocks are preserved within the central sector. The f elsic rocks include thick lenses of volcaniclastics with large, quartz-eye-bearing clasts, but the known metal deposits are not associated with these. Both of the deposit areas, the Hackett River area in the northern domal sector and the 'A itch ' Lake area 40 kilometres to the south in the central sector, are near the tops of relatively thin atypical volcanic sequences above suspected basement rocks. The Yava deposit near 'A itch , Lake overlies a unit of subaerially deposited, welded, andesit ic ash flows and the Hack ett River deposits overlie highly metamorphosed volcaniclastic rocks that include suspected ignimbrites.The deposits are notably argentijerous and lead-rich. They consist of stratigraphically zoned sheet-like bodies of iron sulphides, sphalerite, galena and chalcopyrite underlain by altered rocks containing chalcopyrite stringers. The Yava deposit was formed where hydrothermal fluids exuded through the fractured floor of a flooded caldera basin. The Hackett River deposits may have been formed in a similar setting and it is not inconceivable that all the known deposits in the belt were formed in a single large caldera basin, although there is no independent evidence for the required major fault separation between the Hackett River dome and the 'Aitch' Lake area."

Jan 1, 1980

By V. L. Burdick

A literature review of current uses of Mn02 in ceramic applications with suggestions for future research. Historical background, oceanographic distribution, geology, exploitation, law and politics. Uses of Mn02 in ferrites, semiconductors, catalytic processes, thermo-luminescence and photochromic materials. Select bibliography of 33 items, plus 129 references.

Jan 1, 1980

By R. Le Houillier, M. Nagamori, A. J. Plumpton

"Asbestos tailings are a typical serpentine, hydrated magnesium silicate, consisting primarily of antigorite and a few per cent of unrecovered fibrous chrysotile. Serpentine has unique thermal properties in that dehydroxylating calcination at 600 to 700°C can yield an amorphous structure in which most of the magnesia is liberated from the original bond with silica and thereby rendered chemically active. The amount of activated magnesia can be quantified by selective leaching with a weak acid such as acetic acid. Many wet processes have been proposed to extract magnesium values from calcined or natural serpentine by means of various acids and their ammonium salts. However, the only commercial utilization of serpentine today is found in dry processes such as the production of fused magnesium phosphate fertilizer .The present paper reviews the physical chemistry of the dehydroxylation of serpentine and also various wet and dry processes in order to provide a general view regarding the chemical transformation of asbestos tailings.IntroductionAsbestos fibers occur as chrysotile, a serpentine polymorph. More than nine tenths of mined asbestos ores consist of massive non-fibrous serpentine, primarily the polymorph antigorite, which is discarded as tailings after fiber extraction. For many decades, Quebec has been a world leader in the production of asbestos fibers. As a result, colossal tonnages of serpentine have accumulated in the Eastern Townships'!'. Serpentine minerals are found in large deposit s throughout the world, and significant research efforts have been made, particularly in Japan and the USSR, mostly in attempts to extract magnesia or silica values therefrom.The chemical composition of serpentine (chrysotile and antigorite) may be ideally expressed as Mg3Si2Os(OH). which corresponds to 43.7% MgO and 43.3% SiO2. Natural serpentines often contain a few per cent of Ni-bearing magnetite and other impurities, and therefore the contents of MgO and Si02are both about 40% or lower.Serpentine (hydrated magnesium silicate) is virtually insoluble in weak acids. However, when dehydroxylated under controlled conditions, ' it decomposes to an amorphous state in which magnesia and silica are isolated and chemically active. The magnesia so activated is readily soluble in weak acids. This unique characteristic of calcined serpentine, first discovered in 1942,, has since attracted the attention of innumerable researchers, whence many processes have been proposed."

Jan 1, 1980

To reduce needless paging of persons by all phones in a mine or mill, while retaining all-location page capability. Approach Standard pager phones of any manufacturer are modified to include the option of selective calling and message holding. How It Works All commercial mine pager phones presently rely upon voice paging via a loud-speaker. When a page is initiated, every phone in the system broadcasts the audible voice page, even phones in locations where the desired person could not possibly be. The advantage of this scheme is that whole-mine paging occurs. The disadvantage is that persons soon begin ignoring pages because they occur all the time, and most are for someone else. Also, it requires considerable battery power from all phones making it necessary to change batteries very frequently, even in phone locations where personnel rarely go. In addition, if a voice page is made and not heard, there Is no way to leave the message. Therefore, persons who at a later time come near a phone, have no way of knowing a page was made and was not acknowledged. This results in situations that often have a direct bearing on safety and productivity.

Jan 1, 1980

By E. A. Khopunov, V. I. Revnivtsev

The process of triboelectric separation from the point of view of its potential for selective separation of various mineral particles can be described as "dry flotation." Large scale practical applications of this technique are limited because suitable models which can describe contact charging of mineral particles have not been developed. Among the various concepts a promising one is an attempt to change development in dielectric minerals within the limits of contact phenomenon in semiconductors. Experimental investigations reported in this paper indicate that the charge development is mainly a result of contact electrification of dielectric minerals characterized by "donor" and "acceptor" type energy spectra due to lattice defects.

Jan 1, 1980

Urban development to the south of Sydney is approaching areas of current and proposed coal mining. Already some structures and residential areas are affected by mining subsidence.Subsidence resulting from either conventional pillar extraction methods or longwall mining has been monitored for 15 years to enable the characteristics of the surface deformation to be determined.The vertical and horizontal displacements of survey stations on the surface are monitored and the results arc used to calculate subsidence, changes in slope of the surface, curvatures along the subsidence profile, and the ensile and compressive strains. These features are in turn related to the underground extraction to give a description of surface subsidence and the development of subsidence with time.Subsidence investigations have been carried out over all or part of the workings of six collieries in the Southern Coalfield.Two case histories illustrate the procedure in the investigation of subsidence phenomena. The first example is the study of the subsidence over a series of longwall panels in one seam and the second is a study of subsidence over pillar extraction in two seams one above the other. From the results of the investigations the effects of panel widths on subsidence are determined.This and other information assists mine planning in areas where surface movement and deformation are important considerations.

Jan 1, 1980

By Creasey JW, Rixon KL

Underground mining in the Bowen Seam has shown that the majority of outbursts have co- incided with faults, igneous dykes and sills, stone roof rolls or some combination of these. The coal measures are deformed principally by N- S trending, easterly dipping thrusts presumed to he associated with the major, reverse Collins- ville Fault. The old Collinsville State Mine records suggest that thrusts and strike-slip faults have been common sites of outbursts. In contrast, normal faults have not been outburst- prone. Detailed geological mapping in Bowen No. 2 Colliery 53 east and west panels has been carried out in the hanging wall of a thrust zone of 6.1 m throw. The associated sheared coal has been defined and several fracture sets delin- eated. Sheared coal can be observed up to 170 m from this thrust zone, but this is dependent on the vitrinite content of the upper seam section worked. Fvidence indicates that outbursts have crnrroJ only in extremely sheared coal. Curious spherical- to cylindrical-shaped c,,.31 ohjects ("apples" and "rods") are related to the deformation in the vicinity of the thrust zone. The frequency of rods rises from 0 at 31)0 m, to I per metre at 150 m, and to 2.5-8.5 per metro at 10 m from the -

Jan 1, 1980

By Rawlings C. D

An assessment is made of the potential for thick seam underground mining of black coal in Australia. A brief summary is given of the geomechanical environment and previous mining history existing in a number of areas of particular interest from the point of view of thick seam mining. A classification of thick seam mining methods is presented with emphasis on the critical geomechanical para- meters influencing the performance of such methods. A summary is made of perceived geomechanical research requirements related to thick seam mining in Australian coalfields.

Jan 1, 1980

By B. Ladanyi

An adequate knowledge of the overall behavior of a rock mass at a given site is fundamental to the satisfactory design of a rock slope. The be- havior is controlled by a variety of factors, in- cluding rock type, geological structure, stress and ground water conditions. There are essentially three lines of approach that may be used to obtain information on the in-situ rock mass behavior for the purpose of the design of a rock slope: (1) Direct measurements of rock mass properties by means ol laboratory and field tests. (2) Evaluation of rock mass properties from a study of slope failure case histories and sta- tistical information on stable and unstable natural rock slopes. (3) Evaluation of in-situ behavior of rock mass by using a physical or mathematical model technique.

Jan 1, 1980

By L. S. Gormely

El presente texto describe el desarrollo del proceso de lixiviación adecuado en canchas para un yacimiento en óxidos de cobre. La lixiviación en canchas es una alternativa de tratamiento útil que se considera para aquellos óxidos cuya ley sea demasiado baja para procesarlos por trituración fina y lixiviación por agitación y que presenten dificultades técnicas para someterlos a lixiviación en tinas. Así, en el sistema de canchas, la lixiviación será más rápida y más eficiente que en una simple lixiviación en pilas.

Jan 1, 1980