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By Jeffrey Shawn Peterson

The testing procedures of the U.S. Mine Safety and Health Administration specify that intrinsic safety acceptance tests be conducted using a standard tungsten-cadmium electrode configuration in the break- flash apparatus. However, in realistic mining environments, other materials may be more likely sources of sparking. Information defining the probability of spark ignition between common materials such as aluminum, brass, copper, lead, tin, cold-rolled steel, and stainless steel is of more practical value in determining ignition hazards. The U.S. Bureau of Mines has completed an investigation of the influence of material on the ignition probability using the breakflash apparatus. By comparing ignition currents or ignition voltages corresponding to a probability of one ignition per thousand sparks to those found previously for cadmium, a margin of safety may be estimated for each material. This report presents the results of an investigation into the influence of disk electrode material on the probability of ignition.

Jan 1, 2002

By J Taylor, L Richards, M McKenzie

When a collapse in its services shaft caused rapid gas build up and its premature closure in. 1951, the Blackwater Mine at Wiauta was in full production with significant ore reserves yet to be mined. A total of nearly 23 tonnes of gold was produced from the mine during its 44 year life. It was New ZealandÆs deepest underground mine, producing gold from an extensive sub-vertical mineralised quartz reef that averaged 0.6 m in width. Mining was by stoping between adits and short shafts, latterly with the main mine access through the 840 m deep Prohibition shaft. Macraes Mining Company Ltd are presently investigating the possibility of reopening the mine. This paper outlines a preliminary assessment of the main geotechnical factors for achieving the reopening, using recent exploration and old mine information. The greywacke host rock mass in the vicinity of the quartz reef has been evaluated using both these sources, and the paper discusses how the geological structure, intact and rock mass strengths, the rock mass defects, in situ stresses, and groundwater inflows may effect the reopening and support of the prohibition shaft, the excavation methods and support for a new supplementary shaft, and the likely excavation and support requirements for working adits and stopes in the rejuvenated mine.

Jan 1, 1996

By Camier R. J, Perry G. J

Extensive deposits of brown coal exist in the Gippsland Basin, primarily in the Latrobe Valley. The total quantities of economically winnable coal in this region of Victoria and in other smaller fields are large enough to adequately assure Victoria's future electricity needs and to also provide large quantities for alternative applications, including liquefaction. As a result of the recent conflict in the Middle East attention has again been focussed on the production of synthetic fuels from coal. There have been many investigations over the years into the production of oil from Victorian brown coal. The purpose of this paper is to summarise the scope, objectives and major findings of these studies, with the emphasis on the direct hydrogenation route for converting brown coal to oil. The principal alternative processes are carboniastion and hydrotreatment of the product tar, or gasification and Fischer Tropsch synthesis of liquids from the product gas. The attractions of Victorian brown coal which have encouraged these studies include: ò the vast reserves of Victorian brown coal and the favourable conditions for low cost mining, ò the high quality of the coal (low ash, sulphur and nitrogen contents), ò the high reactivity of the coal giving high yields of product in hydrogenation to liquid fuels, ò the extensive data base available on the resource and its characteristics, and ò the availability of a skilled workforce and extensive infrastructure in the Latrobe Region to support a major resource development project. These advantages have been partially offset by: ò the high moisture content of the brown coal and the cost of drying, and ò the priority previously given to electricity generation in the allocation of the brown coal resource.

Jan 1, 1992

By Holly J

The period following World War II has seen many changes in stoping techniques at The Great Boulder Gold Mine. The new methods resulted in improved unit production figures, and have given some relief from the rising worldwide cost spiral in the post war years.Significant production figures are shown graphically in...

Jan 1, 1956

By A. W. Bester

Paper written on project work carried out in partial fulfilment of B. Eng. (Mining Eng.) Cullinan Diamond Mine currently handles 3.2 million tons of run of ore per annum. This is done by means of an underground train system, which is located at 763 metre level. Four trains, one in each quarter of the pipe, collect ore from passes and transport it to centrally located tips in the north and south of the pipe. The ore is then split into coarse and fine fractions. The coarse fraction proceeds to the primary crushers in the north and south. Historically, mining has been performed in such a manner that an equal amount of ore has reported to each quarter of the pipe. However, the tonnage profile of the mine will change such that the ore will no longer be split equally. For approximately five years the majority of ore will report to the east and thereafter most of the ore will report to the western portion of the mine. This will continue for the remainder of the current infrastructure level?s operational life. Coupled with this is the fact that the mine is aiming to increase its annual production to 3.8 million tons. The result is that the current ground handling system cannot accommodate the additional tons and therefore alternative ground handling options have been investigated. The continued existence of Cullinan Diamond Mine relies on finding a system that can economically handle the additional tonnage. Three options were investigated. Firstly, a train option, which would be an upgrade of the current system, was investigated. Two truck options were also investigated, the first of which was a conventional truck option. The second truck option was more interesting and involved an unfamiliar Combi truck system. The truck options were investigated primarily due to the fact that the block height of the BA West (a new production block) can be increased by 15 meters if a truck option is decided upon. This would create a significant increase in revenue for the BA West project. Each of the options was assessed in terms of its physical and financial feasibility. In terms of the physical constraints, it was found that all three systems could work. Detailed financial analysis indicated that either of the two truck options would be a suitable solution. However, due to the limited information regarding the Combi truck option, it should be further investigated. This applies particularly to the actual running and maintenance costs for the equipment.

Jan 1, 2005

The emergence of China as a global economic power has not been without its birth pangs and the current coal market is testimony to this. Traditionally the coal market has been controlled by mature economies that functioned along balanced lines of supply and demand. The emergence of China and India as major forces in the international market has shifted this balance of power from mature economies to the developing economies of China and India. Of late Chinese Central Government policy has caused wide swings in the supply of Chinese coking coal and thermal coal to the international Asian markets. This has resulted in huge increases in demand for coal from producers in Australia, Canada, Indonesia, USA and Russia. Additionally since the late 1990s the liberalised Chinese economy has been growing by between nine to 12 per cent per annum. The corresponding rise in the standard of living of their 1.4 billion people has resulted in a strong demand for raw materials, initially met by domestic production and more recently met by the importation of raw materials including iron ore, oil, coking coal and thermal coal. Commensurate with this growth in China has been the emergence of India (pop one billion) as another major developing economy in the region. Whilst the Indian standard of living is lower than that of the Chinese, this subcontinent still has some 300 million people with middle class consumption demands. India is a major importer of oil, coking coal and thermal coal. It exports iron ore to China with growth parallel to China (seven to nine per cent per annum). These combined new demands from India and China have put unprecedented pressure on the global supply of coking and thermal coals. These pressures are reflected in the current world spot prices for coking and thermal coals which are at historically high levels. Whilst current demand from China and India is high it is anticipated that new projects will partially satisfy this increasing demand. Expectations are that overall thermal and coking coal prices will rise steadily. This paper seeks to identify the potential effects of Chinese and Indian economic growth on the international markets for coal.

Jan 1, 2004

By Litvinenko V. I

Being a source of structural materials for many centuries, the modern image of the ferrous metallurgy is burdened with obsolete technologies with disregard towards new environmental protection requirements. The production cycle of metallurgical products have two clear-cut stages: I . production of liquid metal and casting into steel billets; and 2. processing of steel billets in solid state under high temperature to produce various shapes and profiles of metal products. Plastic deformation of metal at the second stage is least associated with environmental pollution and is presently being provided with more and more advanced equipment.

Jan 1, 1999

Tunnelling under squeezing ground conditions poses significant challenges. There are fundamental differences in the choice of support for mining as opposed to civil engineering. This paper reviews ground support strategies that have been used to control large deformations in mining excavations based on field data from five different mines in Australia and Canada. Recommendations are made for improved ground control strategies in squeezing rock conditions.

Jan 1, 2008

Predicting the future is a task that should always be delegated. If that is not possible, then stating your views confidently, but retrospectively, is preferable. Hindsight encourages clarity of thought and sharpens perception. When all else fails one can look back into history and see the trends, evaluate the current situation and project it a little way into the future - in this case 10 years. In exploration the rate of change has been increasing over the past 20 years. With expected developments in technology, legislation, and their sociological impacts, we will see such rapid change over the next decade as to make us uncomfortable, unless we are prepared for it.   The social obligations of our industry also have changed enormously over the past 20 years and are still changing. This will lead to further changes in the way we conduct our business if we wish to stay in business. As exploration technology improves, a further dimension is added by the expectations of the communities in which we operate. This extra dimension needs to be quantified so that we not only keep up with current developments but also get ahead of the game. This paper is based on the New Zealand experience, some of which will be familiar to mineral explorers in other countries.

Jan 1, 1997

By Met M, Orr C. W, Met B. E

As was mentioned in the last paper of this series(l), magnesium was added to lead with the idea that it would act as a de-oxidiser. The magnesium lead alloys give rise to an inter-metallic compound of the composition Mg2Pb(2) and it has some remarkable properties. It is known to disintegrate on standing in the atmosphere and it confers this property also on lead alloys in which it occurs. Magnesium forms a solid'solution with lead, and according to Kurnakow, Pogodin' and Vidusova(S) the limits of solubility are as follow...In conformity with the practice used in preceding series, the limit of concentration used in the present investigation was 0.1 %. Accordingly, it would be expected that all the alloys used would consist of the solid solution and the detrimental Mg2Pb would be absent. Whilst this was the case, it...

Jan 1, 1939

By Russell Clough

The Pacheco Pumping Plant is situated on the west end of San Luis Reservoir in western Merced County, California. It is designed to draw water from the reservoir and pump it into a 3,500,000 gallon regulating tank. The water then flows entirely by gravity to the Coyote Pump Station in Morgan Hill, a distance of 40 miles, where it is pumped into Anderson Reservoir. This water is used to recharge the depleted groundwater table in the Santa Clara Valley. Eventually, some of the water will be diverted to Hollister in San Benito County and to Watsonville and Santa Cruz in Santa Cruz County. The owner is the United States Bureau of Reclamation. The underground work consisted of a fifteen foot finished diameter surge shaft 250 feet deep to the crown of the pump chamber; a twenty foot finished diameter pump chamber which declined from the shaft at 14.2% for ninety feet and then ran horizontally for 180 feet; and twelve each five foot diameter steel lined intake shafts 240 feet deep which intersect the pump chamber in the horizontal section. (Figure 1) Upon completion of the pump chamber, the contractor had to dewater the existing tunnel under the reservoir, excavate the remaining fifteen foot plug, and concrete the transition. The low bidder for this contract was Underground - Continental-Heller at 414,456,000. Excavation of the open cut for the pumping plant and surge shaft began on April 14, 1983. This was performed using a Koehring 1066D backhoe, dozer, trucks, and two Cat 631 scrapers. The excavation was started at the surge shaft so that the grouting could begin

Jan 1, 1985

By Lawrence J. Froisland

To aid in minimizing adverse environmental impacts of mining and mineral processing, the Bureau of Mines studied changes in soil characteristics in topsoil stockpiled during mining operations. Topsoil stockpiles in arid areas of New Mexico, Utah, and Wyoming were sampled over a 1- to 8-yr period to determine any changes in physical, chemical, or biological parameters in the top 15 ft of soil. Parameters examined in this study included soil moisture, pH, electrical conductivity, and cation exchange capacity; total nitrogen, organic carbon, carbon to nitrogen ratio, extractable potassium, and soluble phosphorus levels in the soil; general levels of bacteria activity in the soil; and productivity of the soil as measured by shoot yield in growth tests. Data were analyzed by multiple linear regression to determine possible effects of stockpile age and depth. Bacteria population counts, used as an indicator of goner l bacterial activity, was the only parameter found to be significantly correlated with stockpile age and depth at more than one site. Bacterial activity increased with depth at the two sites where it was measured. Activity increased with age at one site and decreased with age at the second. Significant changes in soil pH, electrical conductivity, and moisture were significantly correlated with stockpile age and depth at single sites. This study did not show significant, consistent deterioration in soil characteristics or growth yield of topsoil stored in stockpiles.

Jan 1, 1987

By J. Trckova, P. Prochazka

Physical models from equivalent materials satisfying geometrical and physical similarity have been constructed. A special technology of simulating the excavation of an opening at the front part of a tunnel and of measuring the deformation at the tunnel face was applied. The results yielded by the physical models were used to formulate constitution relations in the numerical solution. This coupled modelling enables us to predict the behaviour of tunnel structures more accurately. On a construit des modèles physiques, réalisés en matériaux équivalents et répondant aux conditions de ressemblance géométrique et physique. Sur ces modèles, on a utilisé une technologie intéressante de simulation du forage du tunnel et de la mesure de déformation du front de taille pendant le forage en progression. Les résultats donnés par les modèles physiques ont été utilisés pour formuler les relations de constitution dans la solution numérique. Une telle construction de modèles combinés permet de prévoir plus précisément le comportement de la structure du tunnel. Es wurden physikalische Simulierungsmodelle aus äquivalenten Werkstoffen konstruiert, welche die Bedingungen der geometrischen und physikalischen Ähnlichkeiten erfüllen. Bei diesen Modellen hat man die interessante Simulationstechnologie des Tunnelvortriebs sowie die Verformungsmessung beim Tunnelabbaustoß während des Vortriebsvorgangs eingesetzt. Die Ergebnisse der physikalischen Simulation wurden zur Formulierung von Konstitutionsrelationen in der numerischen Lösung genützt. So eine kombinierte Simulation erlaubt eine genauere Prognose des Benehmens der Tunnelstruktur.

Jan 1, 2003

By NA UMC

Abstract Booklet

Dec 1, 2022

Sapporo-Iwanai district is located at the intersection of the northeast Japan arc and Kuril arc, associated with the subduction zone. This area is characterized by Miocene submarine volcanism followed by Plio-Pleistocene subaerial volcanism.   Koryu, a small epithermal Au-Ag deposit, occurred in Pleistocene (1.4 - 0.85 Ma) within Miocene sedimentary rocks near a subaerial andesitic volcano, while Toyoha, a large epithermal Pb-Zn-Ag (-Au) deposit, also occurred near a subaerial andesitic volcano. Although most of the base metal deposits formed in middle-late Miocene, Toyoha formed in Plio-Pleistocene (2.93 - 1.60 Ma) within Miocene volcanic and sedimentary rocks. This epithermal mineralization was partly overprinted by xenothermal Cu-Sn-In(-Au) mineralization (2.68 - 0.49 Ma).   Hydrothermal alteration differs vastly between Koryu and Toyoha: host rocks at Koryu were not intensively altered, although wall rocks adjacent to veins were silicified, while those at Toyoha show intensive and extensive neutral-pH alterations. Geological and chronological studies show that middle~late Miocene (12.5 - 8.4 Ma) alteration was pervasive and overprinted by Plio-Pleistocene (2.93 - 0.49 Ma) alteration. The base metal veins in the middle-late Miocene were not well developed, but were large in number with great depth.   These studies show that the hydrothermal activity at Koryu is rather small and short-lived, while that at Toyoha is large, long-lived and characterized by overprinting of different hydrothermal systems. The subaerial magmatic activities yielded not only the andesite lavas, but also generated hydrothermal solutions for the formation of both Koryu and Toyoha. The metals were possibly derived from such magma. At Toyoha, the hydrothermal solutions could also remobilize metals from old ores.   The size, life span of magmatic-hydrothermal system, and overprinting on the old mineralizing systems could constrain the type of metal deposits (precious and polymetallic deposits) nearby subaerial andesitic volcanoes in Plio-Pleistocene.

Jan 1, 2005

By F. J. Chernosky

Most previous studies of coal flotation utilized chemically pure reagents. Since such reagents are not available in quantity, a study of various wmmercially available reagents as frothers was undertaken. Flotation procedures similar to those used in a large number of commercial coal flotation plants were employed. The reagents used were compared on yield-selectivity-wst basis. The selectivity was found to be relatively constant with yields above 70% but the reagent cost varied greatly. The types of reagents available were compared. In the past, a number of papers have been written on the use of various reagents as coal flotation frothers. For the most part, these have been an attempt to correlate the intrinsic chemical and physical proper- ties of the reagents or reagent groups to the floata-bility of various fine coals. Because of the type or nature of evaluations made, chemically pure reagents were normally used. Generally, these reagents are unavailable in commercial quantities. Therefore, the results obtained with these reagents were usually limited in usefulness to the plant operator or metallurgist. This paper presents the results of a study in which commercially available forms of various reagents were used as flotation frothers. Flotation procedures which would conform in general to those employed in a large number of commercial coal flotation plants were utilized. The objective of the test was to compare these reagents on yield-selectivity-cost basis, that is, 1) the yields obtained, 2) the ash levels obtained and 3) the reagent cost relating to these results. REAGENTS The reagents employed have been grouped into the following chemical classes: 1) aliphatic alcohols, 2) terpines, 3) glycols (synthetic water-soluble

Jan 1, 1963

By M. M. Makhofane

Anhydrous zirconium tetrafluoride can be used as a precursor for the manufacturing of nuclear-grade zirconium metal. This can be done by fluorinating plasma-dissociated zircon with ammonium bifluoride in a batch reactor. This paper describes the batch process. It was proved that anhydrous zirconium tetrafluoride can be manufactured by this route as confirmed by X-ray diffraction. The process shows potential for scaling up to the kilogram scale and possibly the tonnage scale.

Jan 1, 2012

By Derek T. Novotny

Blasting cap precision is of major importance to advanced blast design. New technologies have introduced the use of microchips within detonator casings in the hope that the electronic control of the timing element will increase the accuracy of the cap and therefore improve the results of perimeter control blasting applications. The electronic detonators have proven to be accurate in timing tests done to date. They boast cap scatter results to microsecond accuracy, but the question is, does this degree of accuracy actually prove to be beneficial during practical use in the industry, or are conventional technologies applicable.

Jan 1, 1998

By E. W. Thorton

"This paper is intended to show that grinding media can effect flotation results, and in some instances the results are vastly different. I do not suggest that autogenous grinding is beneficial in the separation of all complex base metal ores, in fact I know of a case where autogenous grinding would be disastrous to any selective flotation. I do however contend that prospective flow sheets and reagent balances of any complex base metal ores should be tried with both types of grinding. I feel fortunate that the paper to be presented later in this meeting by Rene Klymouski will, I think, compliment and perhaps explain some of the results of my research.This paper will be in four parts. The first part deals with a literature survey on the subject. Surprisingly enough, very little information has been printed on the subject. The second part deals with results obtained in bench scale tests on an ore from Chester Mines Limited. It was in these tests that we realized that steel grinding was giving us serious problems. So bench scale tests are shown giving results with a stainless steel grind, a mild steel grind and a grind in a ceramic mill with ceramic billets.The third part of the paper deals with results obtained in the Mines Branch Pilot Plant, when again we ground the ore with three different types of grinding media. Incidentally, this has been the only pilot plant test made at the Mines Branch in which flotation products were made on both steel grinding and autogenous grinding on the same ore. The fourth part deals with two other New Brunswick ores and is intended to show that changing the grinding media effects ores other than that of Chester Mines Limited."

Jan 1, 1973

Waitemata Tectonic Event(25 Ma ago) created a subduction system from the northeast of Northland, causing: (1) the emplacement of the Northland Allochthon (24-23 Ma) which provided argillaceous limestone and serpentine to Northland, and minor copper to both there and East Cape (located off Northland then); and (2) Northland volcanism (from 22 Ma), which lacked economic mineralisation. The Kiwitahi Tectonic Event (1714 Ma) caused: (1) a realignment of volcanism - from coastal western Northland, to west of the Hauraki Plains (Kiwitahi); (2) a start to the migration southwards from Northland of (a) the Alpine Fault System towards Marlborough today, (b) subduction towards Cook Strait, and (c) volcanism towards Taranaki-to-Bay of Plenty (initially through Coromandel, Kiwitahi, and offshore west coast); and (3) a start to rhyolitic volcanism & associated hydrothermal activity. The latter caused epithermal mineralisation, providing in Coromandel the best known North Island metalliferous deposits. Andesitic volcanism has been active in both of these two contrasting, subequal belts since 22 Ma. Rhyolitic volcanism and hydrothermal activity was wholly restricted to the eastern Marshall Belt, with an abrupt limit to economic mineralisation at the Volcanic Divide (within Hauraki Plains) and a major change there to basaltic volcanism of the western Searle Belt. The Kaimai Tectonic Event (5-1.5 Ma) caused: (1) a temporary reversal in volcanic migration in the Searle Belt, and a duplication of rhyolitic & hydrothermal activity at Waihi (Marshall Belt); (2) the rotational rifting of both the Central Volcanic Region (by 30¦) and the Hauraki Rift (10¦), causing major curvature of the North Island and New Zealand, and the transfer of the offshore subduction system from Coromandel to East Coast; and (3) an effective end to Coromandel mineralisation. Post-Kaimai Volcanism (1.5-0 Ma) included: (1) andesitic volcanism in the Searle Belt, yielding the western coastal titanomagnetite deposits; and (2) andesitic, and rhyolitic & hydrothermal activity in the Marshall Belt - the latter providing geothermal energy, sulphur, and pumice/perlite deposits. Post-Subduction (Intraplate) Volcanism (10-0 Ma) developed in a steadily expanding northwest region of relative tectonic quiescence, as subduction and its volcanism migrated southwards. Intraplate volcanism was predominantly basaltic, providing excellent aggregate; but less common rhyolitic & hydrothermal activity provided geothermal potential and mercury at Ngawha and at Puhipuhi, and halloysitic clays of extreme brightness elsewhere in Northland. This volcanism has reached as far SE as Mayor Island, providing an early New Zealand mineral resource - obsidian.

Jan 1, 1997