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By B. C. Lewis

Have technological advancements in underground coal mining driven people's skills to new highs or have the expanded skills of mining people driven the industry's technological advancements. Who knows? What we do know is that both our technology and our people have made meaningful and significant advancements. Overall, longwall systems continue to increase productivity and retreat faster. Globally, gate road development is the primary bottleneck in a longwall mine. The primary bottleneck in gate road development is roofbolting. Generally, roofbolting is the bottleneck in room and pillar operations as well. This paper will present an integrated manufacturer's (Joy Mining Machinery) vision of the future in comparison to current equipment performance. Particular emphasis will be placed on roofbolter technologies.

Jan 1, 1999

By K. Meyer

"The largest cost centres of the David Bell Mine concentrator are grinding, leaching and effluent treatment. Optimizing results during the 6th year of operation are listed below: o SAG mill slurry density control and operating strategies improved liner life and media consumption by 10 and 25%, respectively.o Poly-met liners clad the SAG mill except for the feed end. Lower noise levels and reduced mill downtime have resulted in an improved and more efficient workplace (time required for liner changes is 2 to 3%).o A comparative grinding media study using seven different marked media at the same time showed media wear rates range 120 to 198 mg/kWh and ball mill charge replacement frequencies of 8.3 to 13.1 per year, and that a meaningful wear test must include all media to be tested at the same time in the same mill. High quality carbon steel cylinders had the best economics.o Pre-aeration, using pure gaseous oxygen is accomplished in pipe reactors. Small bubble generators provide oxygen in the first three leach tanks. 1500 to 3000 kg of oxygen is consumed per day. Leach kinetics have improved and trends indicate increases in gold recovery of three to seven ounces per day at reduced costs. Effects of reduced cyanidation of accessory metals on the effluent treatment plant will be discussed in a separate paper."

Jan 1, 1991

By Charles A. Bankston, John C. Rowley, Robert J. Hanold, Joseph W. Neudecker

The basic concepts and processes of soil and rock melting as applied to excavation technology are reviewed. The electrically heated, small diameter prototype penetrator development sequence is presented. Emphasis is placed on the different methods of handling the fluid rock and soil melts and their significance in providing new solutions in hole support and debris handling problems. The refractory materials requirements, penetrator life and electrical heater technology are presented. Consolidating penetrators, which form stable glass-lined holes in low density rocks and soils, require no debris removal and will find applications in horizontal holes for utilities, cables, and pipeline installations. Extruding penetrators are being developed to make holes in dense, hard rocks. Melt is conditioned into a variety of debris forms, i.e., glass rods, pellets or rock wool, selected to match appropriate debris handling systems. Unique use in drilling into very hot rock or magma for geothermal exploration or production wells is projected. Some of the results of laboratory and field tests of these devices are compared with theoretically derived operating performance. Coring-consolidating penetrators for geological sampling in alluvium are projected to larger diameter self-propelled and guided coring devices for prospecting along proposed tunnel alignments. Application to the melting of annular shafts for pipeline support piles in difficult conditions such as permafrost has been scoped. Conceptual design studies of large diameter tunneling equipment have indicated the system contributions and economic aspects of rock melting relative to material comminution, wall and roof support and materials handling.

Jan 1, 1974

The Zeehan field has yielded over 190 000 tons of lead and 26,000,000 oz of silver. Moh of the production took place between the initial discovery of silver-lead ore in 1882 and 1920, and the greatest part was extracted from fissure lodes in the Proterozoic to (?) lower Cambrian rocks. It is demonstrated that the prosperity of the mines relied upon the silver content, which is apparently highest in these beds, particularly where spilitic rocks are associated with them. In contrast, galena occurring in orebodies emplaced in the Gordon Limestone is low in silver.Most of the workings are relatively shallow due in some cases to enrichment related to erosion surfaces.Fault zones within a complex anticlinal structure exposing the Proterozoic to (?) lower Cambrian formations appear to have been major factors in the control of mineralization.

Jan 1, 1968

By Chao Li, Shuai Wang, Hongxu Li, Lifeng Zhang, Xie Yang

The method of chloride-hypochlorite leaching has the advantages of short process, low pollution and higher in reaction rate compared with the traditional leaching method. In this research, NaCl - NaClO solution is used to leaching gold from a refractory gold concentrate, and the influence of NaCl and NaClO concentration, reaction time to the leaching rate were investigated in this experiment. The raw materials and the leaching residue were characterized by a series of analysis methods such as XRD, XRF, SEM and EDS. Results indicate that the leaching rate and the desulfurization rate can be achieved at 96.26% and 98% with most optimum conditions as follows: NaCl concentration 50g/L, NaClO concentration 200g/L, Liquid-solid ratio 10:1, the best reaction time was 150 mins. And these conditions should be guaranteed pH<8.0, ORP>900mV.

Jan 1, 2015

By Gordon T. Austin

The combined production value of natural abrasives, which consist of tripoli, special silica stone, garnet, and emery, decreased in 1986. Shipments of processed tripoli increased slightly in quantity and 20% in value. Production of garnet, a common iron- aluminum-silicate mineral, decreased 12% in quantity and value. There was a 4% increase in the quantity and an 11% increase in the value of refined garnet shipped when compared with 1985 shipments, a new record high. Production of crude special silica stone decreased 7% in quantity and slightly in value, and shipments of finished special silica stone products decreased slightly in quantity and increased 229% in value. Production of emery, an impure aluminum oxide, increased 77% in quantity and increased 269% in value of product mined and shipped. [ ]

Jan 1, 1988

By P. R. Dugan

Sulfur removal from high sulfur coal has several objectives including: a) reduction of the atmospheric load that contributes to the problem of acid precipitation; b) reduction of ash, which contributes to decreased energy transfer in boilers, as well as ash disposal; and c) alleviation of the social and economic dislocations related to uneven geographical distribution of sulfur in coal reserves. Cost in relation to the value of refined coal will govern the development of an emerging coal refining industry. Estimation of the premium paid by power companies for coal with a low sulfur content is a good estimate of the value that will be added as the result of refining. Estimates of premiums paid in 1984 are $28.65/t ($26 per st) for reduction of total sulfur from 370 to 1% S and greater than $28.65/t ($26 per st) for removal below 170 sulfur.

Jan 1, 1988

Experiments in the bolting of a mine roof were commenced at Elrington Colliery on the South Maitland Coal Field early in 1949, following the appearance of an article in the American publication, &quot;Coal Mine Modernisation Year Book&quot; 1948. Prior to this, although bolting had not been used in the maintenance of satisfactory roof conditions, the principle of roof bolt anchorage had been illustrated in instances such as the hanging of a trolley locomotive power wire using an expanding shell type of bolt anchorage, or the insertion of an eye bolt with a split and wedge, as used to suspend a rope block over a winze being sunk in a metalliferous mine.The experiments at Elrington Colliery were the first efforts in this country to supplement the work of timber supports under a mine roof with systematic placement of roof bolts.Following the series of experiments at Elrington, full scale bolting was commenced at that Colliery in a trackless mobile section in April, 1950.The obvious success of the system at Elrington indicated that it might also be a success in the support of weak roof strata immediately overlying the workable section of the Victoria Tunnel Seam at John Darling Colliery.The system was commenced at John Darling Colliery in April, 1951, in one mechanical section on the Victoria Tunnel Seam, and the scope was gradually widened until by December, 1952, ail&apos;six mechanical units then operating on this seam were working under bolted roofs.

Jan 1, 1954

Uranium exploration over a wide area of the Southern Frame Embayment, South Australia, has defined a number of Lower Tertiary fluvial palaeochannels incised in older rocks. The buried channels contain similar stratigraphicsequences of interbedded sand, silt, and clay, probably derived from the adjacent uranium-rich Olarv Provinee. Uranium mineralization is pervasive within two major palaeochannels, and four small uranium deposits have been found in the basal sands of these channel sequences, at the margins of extensive tongues of limonitic sand.One of the channels is examined in detail with respect to channel morphology, stratigraphy, and rock alteration and the geology and ore controls of the contained uranium deposits are described.A geochemical zonation reflected by variation in limonite, pyrite, carbon, and humic malleI&apos; is defined across one of the deposits. A genetic model is proposed suggesting formation by a uraniferous geochemical cell which migrated down the stream gradient and concentrated uranium on its lateral margins adjacent to the channel bank.

Jan 1, 1978

By J. A. Delgadillo

Computer simulation and mineral modeling was applied to the optimization of a grinding circuit in a plant processing 256 t/h magnetite. These tools were used to develop a grinding and classification configuration to decrease the grade of silica in the magnetite concentrate, which is produced by the plant. Empirical grinding and classification models were finely tuned using plant experimental data. The JKSimMetTM 5.0 software was used to simulate the grinding and classification units. By applying changes in the original circuit, a throughput increment of 100% was achieved with an important reduction in the energy consumption. The silica content in the magnetite concentrate can be decreased by regrinding the coarse fraction of fine screens into a separate ultrafine grinding unit instead of returning this flow to the ball grinding mills.

Jan 1, 2008

By C M. Wawryk, S L. Garwin, J D. Foden

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Batu Hijau porphyry Cu-Au deposit in south-western Sumbawa, Indonesia is an ideal natural laboratory to study the fractionation of iron isotopes in magmatic rocks that range in composition from basaltic andesite to tonalite. Intrusive rocks are associated with a porphyry system that contains well-preserved early hypogene copper mineralisation. We analysed pre-, syn- and post-mineralisation igneous intrusive rocks. We also separated magnetite, chalcopyrite and bornite from hypogene porphyry-style quartz veins, and measured the Fe-isotope ratios of samples by solution multi-collector ICP-MS. Iron isotopic composition of samples from the magmatic suite show an increasing d57Fe with increasing SiO2, supporting geochemical and textural evidence that the Batu Hijau Tonalites underwent closed system fractionation. Equilibrium and co-existing mineral textures allow the calculation of the following preliminary empirical mineral-mineral fractionation factors at 500°C for certain mineral pairs.Iron isotopes have the potential to provide geothermometric data to complement fluid inclusion data, especially where heating stages have operational limitations and where fluid boiling results in a wide variety of inclusion types that may make analysis difficult.CITATION:Wawryk, C M, Foden, J D and Garwin, S L, 2015. Iron isotope fractionation in magmatic-hydrothermal minerals – a porphyry copper case study from the Batu Hijau deposit, Sumbawa, Indonesia, in Proceedings PACRIM 2015 Congress, pp 389–396 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Uranium ore at Sleisbeck, N.T., occurs as lenticular bodies associated with zones of bleached carbonized schists lying between walls of closely folded quartzite. The ore consists mainly of uranium micas with Borne pitchblende.INTRODUCTIONThe Sleisbeck uranium prospect is about 70 miles E. of Pine Creek, and 160 miles S.E. of Darwin (Fig. 1). The prospect consists of a well-defined, E.-W. trending line of hills, about I! miles long. The line is composed of 3 major hills called the Eastern, Central and Western hills, with minor interconnecting hills and outcrops (Fig. 2).

Jan 1, 1955

By N. R. Allen, J. D. Steenkamp

Oxidative roasting is applied on an industrial scale to beneficiate ilmenite concentrates from South African East Coast heavy minerals deposits - the aim is to increase the magnetic susceptibility of ilmenite to allow magnetic separation from chromite. The intention of this paper is to give researchers new to the field an overview of the beneficiation of ilmenite through roasting and magnetic separation, touching on the relevant fundamental aspects of magnetism.

Jan 1, 2005

By G. W. Grove, E. E. Quenon

"INTRODUCTION During September, October, and November 1946 the Safety Division of the Bureau of Mines, off' the United States Department of the Interior, Pittsburgh, Pa., tested four new types of self-contained breathing apparatus and approved them in accordance with Schedule 13C. Approval was granted with the proviso that certain specifications outlined on the approval plate be made fully effective, and with the understanding that established safe practices in training in the care and use of self-contained breathing apparatus are of major importance.The excellent records made during the past 30 years in the safe use of self-contained breathing apparatus, some of which required the almost continuous wearing of apparatus during several hours daily for days, weeks, or months, may be attributed largely to the Bureau's system of rescue organizations, selection of physically fit rescue workers, effective training, and educational work done in rescue and recovery operations during fires or following disasters and in the care and use of self-contained breathing apparatus. Loss of life during wearing of breathing apparatus was due almost invariably to poorly assembled or otherwise defective apparatus, poor physical condition of the wearer, or insufficient training or some incorrect procedure.The newly developed breathing apparatus are of much simpler design than the conventional type used for the past several years; however, it is just as important to select rescue crews carefully and to train them properly in the care, use, and limitations of the new types of apparatus as for the older long-established types, if anything like safety is to be achieved in using them. The Bureau of Mines considers that 1/2-hour and 3/4-hour self-contained breathing apparatus should be used only as auxiliary equipment in mine rescue and recovery work, and their capabilities and limitations should be well understood by those who wear them."

Jul 1, 1947

By Doris M. Hyde

The Bahama&apos;s petroleum-dominated minerals sector constricted again in 1985. The declines were mostly the result of a soft market demand for crude oil and petroleum products. In early 1984, it was a growing unprofitability that prompted Charter Oil Co. to cease using the 350,000-barrel-per-day Bahamas Oil Refining Co. facility that it jointly owns with Chevron Oil Bahamas Ltd. After midyear 1985, because of poor petroleum economics, Chevron announced it would close the refinery, leaving only a maintenance crew. In 1984, the refinery exported less than 26 million barrels of petroleum products. Chevron&apos;s throughput was reported as averaging about 8,000 barrels per day at the time of the announcement. The crude oil transshipment terminal also registered declining activity and financial losses in 1984 and 1985. Transshipments of petroleum in 1985 amounted to about 100,000 barrels per day, one-half as much as in 1982.

Jan 1, 1987

A brief review is given of the history of the Colliery to date together with the reasons for the development of an additional seam.Investigations into the quality of the coal ami its suitability for the production of metallurgical coke and determination of the economic mining limits and coal reserves are discussed. The commencement of mining operations and the inter-seamarrangements necessary for the disposal of coal won are described with the stages in the opening out of the seam itself and the reasons for the installation of a 48-in. trunk conveyor belt. Choke and manning of face equipment are considered and also the work of secondary development and pillar extraction.It is concluded that with modern face equipment and conveyor belt lines, concentrated mining followed by immediate extraction of pillars is practicable and is giving excellent results at Burwood Colliery.INTRODUCTIONBurwood Colliery, the total holding of which now comprises some 3,140 acres of land and 1,450 acres of sea leases, has mined the Borehole Seam since 1883. The early work took place from Nos. 1 and 2 shafts at Glenrock Lagoon and later on at Nos. 3 and 4 shafts at Whitebridge to which the centre of operations shifted in 1893, shaft sinking at this latter area having commenced in 1888.As all the early operations were confined to the Borehole Seam, reserves of coal on this horizon had been considerably reduced by the mid 1930&apos;s, so a cross measure drift was driven to the Victoria Tunnel Seam which is about 300 ft. above the Borehole Seam, and fully mechanized coal winning commenced from the second seam in 1938. Subsequently this cross measure drift was extended to the Borehole Seam and complete mechanization of the south-west sections of this seam achieved by 1945.Four track mounted mechanical units were put into operation in the latter area and these worked in a southerly and...

Jan 1, 1958

By R. P. Killmeyer, W. W. Wen, B. K. Parekh

A continuous pilot-scale test of the GranuFlow Process was conducted using a screen-bowl centrifuge for the dewatering and reconstitution of column -flotation concentrate at a coal preparation plant in Virginia. In this test, a slipstream of the fine clean-coal slurry from the column flotation con¬centrate was treated with a bitumen emulsion before dewatering. The treated products from the screen-bowl centrifuge appeared to be dry and in a free flowing granularform, while the untreated products were wet, sticky and difficult to handle. Test results indicated that the average moisture contents of the dewatered coal products were 35.7%, 35.5%, 32.6%, 29.9% and 26.5% (by weight) with Orimulsion additions of 0.0%, 0.7%, 3.2%, 4.8% and 6.4% (by weight), respectively. The handleability and dust reduction of the dewatered coal products were also vastly improved.

Jan 1, 2000

By K. O. Bennington

Cancrinite is one eonstituentof "red muds," a high-volume waste product of alumina production by the Bayer process. The Bureau of Mines determined the thermochemical properties of cancrinite as part of a program to provide such data for minerals of industrial importance. Cancrinite [Na7.68(A16Si6024)(N03)1.68 (H2O)4.1] was synthesized by reacting aluminum silicate gel with a solution of NaOH and NaN03, and the composition was determined by chemical analysis, differential scanning calorimetry, and thermogravimetric analysis. The heat of solution was determined by hydrofluoric acid solution calorimetry. The standard enthalpy of formation at 298.15 K, ?Hf°298, is ?Hf°298 = -3,487.97 ±2.6 kcal/mol, and the standard enthalpy of formation from the oxides and NaN03, ?H°298, is ?H°298 = -215.20 ±l.8 kcal/mol.

Jan 1, 1983

By S Vianna, K Caldwell, R Silva, T Olson, D Bell

Studies to enhance the FLSmidth forced air machine through changes in the design, showed important improvements through changes in the number of Rotor blades, stator designs, rotor air distribution and other designs features. The main outcomes from this study highlighted that increasing the number of rotor blades increased the selectivity while decreasing power requirements while stators with slots have better results in terms of recovery, flotation efficiency and selectivity than without slots.Also the rotor air distribution makes a difference in the design when comparing different distribution criteria whilst keeping all features of shape and number of blades etc constant. At the most efficient rotor air distribution design, copper recovery reached one of the highest values while keeping good selectivity. The possible explanation for that is the increase in the pump capacity indicated by the increase in the specific power.It was seen as significant that reduction in specific power for some designs tested compared with the then current standard design had an average of 30% less power consumption.As a result, FLSmidth was able to identify new designs that decreased power and improved recovery, as well as, identifying some designs that specifically improved fine and/or coarse particle recovery.CITATION:Silva, R, Caldwell, K, Bell, D, Olson, T and Vianna, S, 2013. FLSmidth flotation developments - Dorr Oliver machines, in Proceedings MetPlant 2013 , pp 413-430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By R. Agius, A. Nacu

"Adoption of the International Cyanide Management Code, regulatory requirements and community concerns have increased the need to implement suitable cyanide destruction processes at gold operations to meet ever more stringent discharge limits. As standards set for the allowable concentrations of cyanide, cyanide compounds and other contaminants may vary from country to country, jurisdiction to jurisdiction, and even from site to site, there is no “one size fits all” technological solution. Currently the most common cyanide destruction processes used in industry are sulfur dioxide/oxygen, hydrogen peroxide and Caro’s acid. Regardless of the process used, cyanide destruction plants must be reliable and achieve permit guidelines at all times. The selection of the most appropriate cyanide destruction process for an operation depends on several factors, including permit discharge requirements, tailings chemistry, location, site-specific climatic conditions and size of the operation. Only after considering all these factors together can the most effective approach be selected to achieve the permit guidelines economically and technically feasible. Finally performing the correct test work program is the most important step to ensure that the correct process design criteria can be determined to accurately calculate capital and operating costs.IntroductionThe adoption of the International Cyanide Management Code in 2005, stricter regulatory requirements and community concerns prompted by environmental incidents involving cyanide have increased the need to implement cyanide destruction processes at gold and silver operations.Process solutions associated with the extraction of gold and silver contain several forms of cyanide. The most toxic form of cyanide is free cyanide, which can be present as a dissociated cyanide anion (CN-) or gaseous or aqueous HCN. Weak or moderately stable cyanide complexes such as those of zinc, copper and nickel are classified as weak acid dissociable (CNWAD). Although less toxic than free cyanide, weak acid dissociable cyanide complexes are considered “ecologically sensitive” forms of cyanide and are regulated in most jurisdictions. In practice, reported WAD cyanide values are comprised of both free cyanide and weak acid dissociable cyanide complexes. Cyanide complexes with gold, mercury, cobalt and iron are referred to as strong acid dissociable complexes (CNSAD) and are much more stable even under mildly acidic conditions. Another term commonly used in cyanide chemistry is total cyanide, which represents all cyanide compounds present in solution, with the exception of cobalt complexes. Total cyanide levels in solutions are in most cases higher than WAD cyanide values and the difference between the two usually indicates the presence of iron-cyanide compounds. Typically, in Canada CNTOTAL levels cannot exceed 1 mg/L in solutions."

Jan 1, 2017