Search Documents

By Y Ren

?ptim?sgtion t?ols nos ope? 0iu ?ingc s?ch as the cche??ling and?pi? k?(i?isatTon tool{ ?ave bg?ome(?osd-dvfective way? to e?iluata open`¦it mi~e!p?n?ept as w?ll asá?}prmv?ng mine?projecW`value> ?owerez

Aug 12, 2013

By J. L. Gillson

The word "other" in paragraph 4, line 11, column 1, page 205, should read "over;" the correct version of reason 2, this paragraph, is: 'L. . . 2) to evaluate the usefulness of certain geo-chemical techniques, V. C. Kennedy and S. W. Hobbs of the USGS had already studied the distribution of copper, lead, and zinc in the soils (both in background areas and over veins) and in the water and plants, providing a criterion for measuring the magnitude and effect of soil contamination; ...9 On page 206, in the top left hand corner of Fig. 1 (in the area bounded by 47°35' and 116°10), the reference to Fig. 3 is incorrect. The area of Pine Creek, South Fork Coeur d'Alene River, and portion of Big Creek (the area which includes, from left to right, Kingston, Pinehurst, Smelterville, and Kellogg) should be identified as that of Fig. 2A. The headings for columns 1, 3, and 4, Tables I and 11, page 209, column 2, were reversed when the paper was printed. The corrected tables are:

Jan 1, 1961

By A Proudman, J Isles, R Lawolo, G Forster

PT Nusa Halmahera Minerals (PT NHM) is an Indonesian joint venture company owned by Newcrest Mining Limited (75 per cent) and PT Aneka Tambang (Persero) (25 per cent). PT NHM operates two underground gold mines, Kencana and Toguraci at the Gosowong mine site in North Halmahera District, North Maluku Province, Indonesia.Due to several major stope overbreak events at Toguraci, the mining method and sequence was reviewed. The method was changed from a bottom up Avoca stoping approach using waste rock as fill material and leaving sill pillars, to a top down open stope method using paste fill without sill pillars.The revised mine plan originally had stoping progressing from the current level to the base of reserves followed by extraction of the sill pillars in the upper levels at the end of mine life. Geotechnical modelling was conducted on the revised mine plan and it was recommended that the sill pillars be taken early due to the risk of them overstressing and being difficult to recover if left until the end of mine life. The backfill material above the sill pillars is unconsolidated run-of-mine development waste rock or unconsolidated rock fill (URF).Due to earlier attempts to extract sill pillars under URF not being successful in the upper areas of the mine, it was stipulated that the URF above the five remaining pillars must be consolidated prior to stoping. Cost benefit analysis showed this to be justifiable due to the high-grade nature of the ore locked up in the pillars.Grout was initially planned to be injected in one pass through self-drilling anchors (SDA) in a 2.5 m pattern. Initial attempts to do this failed due to the SDA aperture and grout consistency. A modified method was employed using poly pipe installed into open holes that were drilled through the sill pillar and into the URF from below. Repeated application at each location ensured full grout consolidation. Drill holes were used to confirm grout thickness as well as add more grout. Design thickness was based on stress analysis.Despite different URF types being present due to varying quantities of fines, the process was similar for each area. The presence of paste in the URF of one target affected the quantity of grout it received.With a design thickness of 4–5 m of consolidation in the URF, depending on stope width and dip, each consolidated pillar (to date) maintained integrity during the stope operation. Some fall of material was anticipated; however, quality assurance / quality control (QA/QC) during grouting, staged stope extraction and careful blast design minimised fall of material.CITATION:Proudman, A, Isles, J, Lawolo, R and Forster, G, 2017. Rock fill consolidation for the extraction of sill pillar stopes at Toguraci gold mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 199–210 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Robert G. Bottge

The Bureau of Mines has engaged m a program to determine the availability of land for mineral exploration and development in Alaska. Land availability, based on ownership and Federal and State laws and policies, is compared with mineral terranes and mineral deposits. This is the fifth of six regional studies, which cover the State with a comprehensive set of maps and data compilations. This study covers an area of 112.3 million acres in western Alaska. In July 1986, 41.0 million acres, 37% of the study area, were available for mineral exploration and development; 14.6 million acres, 13%, were available with restrictions; and 56.7 million acres, 50%, were unavailable. Nearly 65% of the unavailable land is classified as national parks, preserves, wildlife refuges, and wild and scenic rivers. Of the 34.0 million acres of mineral terranes that underlie the study area, 12.9 million acres, 38%, are available for exploration and development; 3.6 million acres, 11%, are available with restrictions; and 17.5 million acres, 51%, are unavailable.

Jan 1, 1988

By Martin H. Stanczyk

Bench scale, laboratory batch attrition grinding tests were made of a coarse commercial kaolin in a stainless steel, 5-inch-diameter attrition grinding machine to study the effect of a number of basic operating variables on particle size reduction and electric energy consumption. The results of the investigation showed that the more important operating variables influencing the efficiency of kaolin comminution and energy consumption requirements were type, size, and shape of grinding media, grinding media to clay weight ratio, peripheral rotor speed, clay slip pulp density, degree of pulp dispersion, and the angular arrangement of the rotor and stator bars. The tests also indicated that variables having less influence on grinding efficiency and energy consumption were pulp temperature, design of rotor cage, rotor clearance, rotor-stator bar interval, addition agents, pulp level, degree of pulp aeration, and chamber liners. The research showed that grinding media had the greatest influence on abrasion of machine parts and that spherical-shaped grinding media were superior to sharp angular or long bladed media with respect to media degradation, machine abrasion as well as grinding efficiency.

Jan 1, 1968

By W. J. Kuit

Since closure in 1968, the Wedge Mine, situated adjacent to the Nepisiguit River in New Brunswick, has been flooding with acidic water containing toxic levels of heavy metals. Cominco Ltd. has undertaken a series of pollution control measures to mitigate the threat posed to the river quality. Included has been a successful treatment campaign in 1976 which discharged in excess of 30 million gallons of high-quality effluent from the accumulated volume of mine water. The sources of contamination have been identified as actively leaching waste dumps. A comprehensive program of permanent corrective measures has been prepared which will culminate in mine backfilling. Once completed, the unacceptable burden of water treatment in perpetuity at a non-producing property will be removed.

Jan 1, 1977

By E. V. Lilford

The South African Minerals Development Act (?the Act?) has been promulgated and will come into full force and effect once it is gazetted. Thereafter, all Old Order mineral rights will have to be converted into New Order mineral rights within a 5-year period, probably by the end of 2008. The conversion of rights will be achieved only with the demonstrated inclusion of empowerment groups in the conversion applications. In addition to the Act, the first draft of the proposed Royalty Bill (?the Bill?) was released during the week beginning 17 March 2003. Comments on the Bill?s contents had to be submitted before 30 April 2003. The contents were to be considered in terms of applicability and acceptability to the South African minerals industry, where after proposed comments and suggested amendments were to be submitted to the relevant State Treasury office. Specifically referring to the Bill, the general response from the industry is one of concern. Since any royalty is tantamount to a tax, the general feeling is that the current mining taxation rates are already internationally competitive and to increase these effective rates, notably at differing rates depending on commodity type, will have an adverse impact on the South African mining industry. A number of these impacts can be mitigated to some degree, depending on the flexibility of the State to address the major concerns.

Jan 1, 2003

By Bernd Kos

The management of waste materials in the aluminum industry is as important as in other basic industries. Due to the high value of the-by products of the melting process and their toxic properties we took the challenge to develop a process technology to reduce the environmental impact and to help industry to get a better yield of their by products/raw materials. In melting operations metal losses due to oxidation are nearly unavoidable, the amount of such losses, however, can be controlled. Aluminum dross actually is a by product and any shop would like to get rid of it in the most economic way. This by product still contains up to 70% valuable metal! In the present work we describe possibilities to separate metal and residues for further processing. Recycling of metal concentrates, selling of dross and dumping of the residues have been the typical solutions up to now. But there are technologies available which are designed to reduce the waste to a minimum or even avoid it altogether. Such alternatives are processing of the dross into materials which can be reused in other industrial processes in order to avoid any dumping. This can be done by separating the metal and the residues by centrifuging and further use of the residues in the chemical or refractory industry. ECOCENT means economical and ecological recovery of aluminum by centrifuging of hot dross. This process, developed by FOCON Austria, is based on the idea of treating the hot dross as quick as possible in a single operation to avoid exothermic losses, intermediate storage and unnecessary handling as well as to save energy. In the ECOCENT process the hot dross is fed without any fluxing salt additions into a converter where the relevant parameters for separation, like temperature and viscosity, will be adjusted. Further big lumps of dross are ground into smaller pieces in order to improve the later separation of the metal. After homogenizing and adjusting the temperature, the hot dross is poured as quickly as possible into a centrifuge. In the ladle or alternatively the mould of the centrifuge the centrifugal forces are used for the separation of aluminum from aluminum oxide, the major constituents of dross. The separated pure metal can either be discharged liquid or as solidified aluminum ring. The design of the device for the production of liquid or solid metal is almost identical. As soon as the centrifuging is finished the liquid aluminum can be poured back into the furnace or can be used for ingot pouring. After the pouring of the metal the "dry" residues are removed just by turning the ladle. Alternatively the aluminum solidifies in the mould and is discharged as a compact ring. The separation of the residues from the aluminum ring is automatic. Due to the batchwise operation the composition of the metal is the same as in the skimmed furnace of origin. The complete treatment cycle needs about 40 minutes. The recovery rate of aluminum is better than 90% of pure metal. This technology is highly flexible by its nature and can easily accomodate various operational requirements. The consumption of energy is more than 50% lower compared to conventional dross processing as the ECOCENT process is using the inherent energy of the hot dross. These extremely good results are not dependent on the aluminum content of the dross even from very dry dross most of the metal can be recovered. The main advantages compared to conventional dross processing are the high recovery rate, the known analysis of the metal and the immediate reuse of the recovered aluminum. The high recovery rate and the pure metal result in a short amortization period. The compact ECOCENT unit needs a minimum of space since extensive handling can be avoided. The electronically controlled process needs no cooling water and is simple, safe and environmentally sound. The residues are free of fluxing salts, their content of metallic aluminum is low and the environmental problems are thus greatly reduced.

Jan 1, 1995

By B. J. Buys

Rock bolt integrity is a critical issue for the mining industry because of its influence on the safety of mining operations. Guided ultrasonic wave testing of the defects associated with resin-anchored rock bolts was investigated. Axisymmetrical and three-dimensional finite element models were built, one of a partially encapsulated bolt and the other of a bolt with a simulated local corrosion crack. Experimental bolts were then installed in a testing block and typical responses were compared to finite element models of different defect scenarios. Encouraging results were obtained for the smaller axisymmetrical and three-dimensional finite element models, as well as during the experimental investigation. It is recommended that software with energy-absorbing elements should be utilized to consider higher frequencies and longer bolts. Once the integrity of models such as these has been established, the models could in principle be used to train neural networks for use in commercial equipment to determine the integrity of the installed bolt.

Jan 1, 2009

By Eugene T. Sheridan

The 24th annual survey of the peat industry by the Bureau of Mines, United States Department of the Interior, revealed that 76 producers in 20 States reported commercial production of peat in 1957. In addition to the States that reported production in 1956, Colorado, Idaho, and Wisconsin produced peat in 1957 Forty-four producers reported humus production; 21, reed-sedge peat; and 22, moss peat production. This total exceeds the number of active plants but several producers recovered more than one type of peat. Fifty percent of the total production was reported as reed-sedge peat, 36 percent as humus, and 14 percent as moss peat. About one-sixth of the total production was raw peat, with no preparation other than being air-dried. The remainder consisted of processed peat prepared for use by cultivation, shredding, and/or kiln drying.

Jan 1, 1958

By Altair Vieira de Souza

O tântalo é um dos metais mais versáteis na engenharia, podendo ser utilizado desde tecnologias espaciais até a biomedicina. Isso incentiva o estudo de novas tecnologias de obtenção do metal a partir do óxido de tântalo (Ta2O5). Neste trabalho é apresentada uma nova rota de obtenção de tântalo metálico a partir da reação magnesiotérmica do óxido de tântalo, usando como ignição o plasma de hidrogênio. Propõe-se um método alternativo ao processo Hunter, que apesar de ser o mais utilizado, é lento, pouco eficaz na produção de grandes quantidades e gera rejeitos degradantes ao meio ambiente. Foram misturados pós de magnésio (Mg) e Ta2O5 em recipiente projetado para permitir o efeito de catodo oco, e então aquecidos a plasma até a temperatura de ignição. Os experimentos foram realizados variando a pressão de trabalho buscando a redução completa do Ta2O5. Os produtos resultantes desses processos foram analisados por equipamentos de difração de raios X. Os resultados mostram que é possível a obtenção de tântalo metálico (Ta) a partir da redução metalotérmica do óxido de tântalo (Ta2O5) usando como agente redutor o magnésio e o plasma de hidrogênio como agente de ignição. A redução completa do Ta2O5 é obtida com o uso de pressões de 4,5 e 5,0 Torr.

Oct 30, 2017

By J. N. Van der Merwe

The data base of failed coal pillars in South Africa was analysed with regard to the time of failure in an effort to develop a method to predict how long after their formation coal pillars will fail. It was found that meaningful results could only be obtained by splitting the data base up into groups that displayed similar behaviour. It was postulated, based on observation and experience, that coal pillars fail by a process of progressive weakening progressing into the pillar from the edges. Minimum pillar dimensions to ensure failure were calculated?these were the dimensions that corresponded to a minimum ?real? factor of safety. From the scaling distance required to reach the minimum safety factor, rates of scaling for the failed pillars were calculated based on the observed real lives of the pillars. It was found that the rates of scaling were unique for different mining areas and that they correlated directly with mining height and inversely with time. Using the derived scaling rates, the predicted pillar lives were back calculated for the pillars in the data base of failed pillars. In two of the three groups, the predicted lives correlated well with the observed lives on a one-to-one comparison. In all cases, the predicted lives were in the same time range as the observed lives. Overall, the frequency of predicted lives closely replicated the observed frequency of observed lives of the pillars in the data base of failed pillars. The method was successful in distinguishing between the data base of failed and a representative sample of intact pillars. While the predictions matched the observed lives of failed pillars, the predictions of expected lives for intact (hitherto unfailed) pillars were orders of magnitude greater. It is now possible to estimate the frequencies of future pillar failures for the purposes of mine closure and undermining of surface structures within broad bands.

Jan 1, 2003

By N. Samman, S. N. Lau

"A series of new, grease-based, solvent free open gear lubricants were developed to meet the demanding service requirements of mining equipment. The use of these products has resulted in better performance under conditions of temperature extremes and in terms of longer component lives. They have gained widespread acceptance within the mining communities for such applications as the lubrication of mining shovels, draglines and ball mills.These products are WHMIS non-controlled and are environmentally acceptable. The benefits and advantages of using this type of product to lubricate mining equipment as well as the field evaluation and experience will be discussed."

Jan 1, 2002

By R Adamian, F. T. Da Silva, D. H. Gameiro

Schytill and Geldart diagrams were developed for the TiO2-C-Cl2 system at 1 073 and 1 273 K, so as to define the hypothetical relations between particle sizes and chlorine velocity for simultaneous fluidisation of mixtures of anatase concentrate and charcoal for carbochlorination. It was concluded that the operating limits on chlorine gas velocity will be controlled by the behaviour of the reducing agent, mainly because of its lower density. An increase in temperature from 1 073 to 1 273 K will have only a small influence on the fluid-dynamic behaviour of the mixture. For bubble fluidisation, the maximum sizes 0.413-0.478 mm for anatase and 0.529-0.611 mm for charcoal will be adequate. When the particle size distribution is large, fluidisation will be feasible only if conducted in two stages, otherwise the residence time of the small particles in the reactor will be very short. New diagrams will be needed for the gaseous chlorides in the second stage

Jun 21, 1905

Removal of As(III) and As(V) in Aqueous Solution There are toxic arsenical species such as As(III) and As(V), and arsenious species have specially strong toxicity. The strong toxicity causes contamination of groundwater and water pollution for the semiconductor production process. This study is concerned with the removal of As(III) and As(V) with various kinds of Mg/Al layered double hydroxides (LDH) containing CO32-, SO42-, Cl- and NO3- as interlayer anionic species. The anion exchange property is different from the kind of layered double hydroxides and the Mg-Al-NO3-LDH is superior in the anion exchange property of As(III) and As(V) due to the nature of nitrate ion existing in the interlayer. The pH condition suitable for As(V) removal is 7.1 or more. If the initial conditions such as 10mg/dm3 of As(V) concentration, 7.1 of pH, 1 m3 of amount of solution and 99 per cent of removal are fixed, the required amount of Mg-Al-NO3-LDH is 0.27kg for two step-batch operations. The As(III) is suitable to oxidize to As(V) before the removal processing.

Sep 13, 2010

By E. Z. Casassa

There has been a recent revival of interest in concentrated coal/water slurries as a substi¬tute for fuel oil or for coal/oil mixtures, particularly in electric power generation. The idea is not a new one. Coal/water slurries were transported by pipeline in the U.S. in the early nineteen-sixties, and the Black Mesa coal pipeline has been in operation for several years, while in Germany, coal/water slurries were being burnt for power generation in the early nineteen-seventies, as described by Merten and Höner (1972). Since coal is not a pure substance but a carbonaceous mixture, the different chemical and physical behavior of coal/water dispersions from different deposits must be understood in order to optimize the properties of the result¬ing slurry fuels. Since minerals which are minor constituents of coal may also strongly affect slurry properties, coal chemistry may vary considerably even within a single deposit. Thus it is unlikely that there will be a single formula for optimizing the slurry properties of all coals, and even the answer for coal from a single source may change with time.

Jan 1, 1983

By AIME AIME

THE John Fritz Medal Board of Award, at its annual meeting on Jan. 21, 1921, awarded its gold medal and diploma to Sir Robert Hadfield for the invention of manganese steel. On June 1, announcement was made that the Board of Award had awarded its gold medal and diploma to Charles Prosper Eughe Schneider for "achievement in metallurgy of iron and steel; for development of ordnance, especially the 75-mm. gun, and for notable patriotic contribution ' to the winning of the war." The award to Sir Robert Hadfield is for the year 1921; the award to Mr. Schneider is for 1922. The latter was made at this time in order that the medal might be presented by the group of American engineers now visiting England and France.*

Jan 1, 1921

By J Parnell, B Manson

Bitumen occurs in the basins in reservoir sandstones, in veinlets close to hydrocarbon source rocks, in veins through lava beds and in sulphide-mineralised veins where it is closely associated with, but predates, the sulphides. The role of organic matter was probably in enhancing metal reduction by creating a low-Eh environment rather than in metal transport. Coeval euhedral quartz crystals or albite in sulphide-bearing carbonate veins provide evidence of an aqueous component to the hydrocarbon fluid

Aug 1, 1995

By D. Bienstock

In connection with air-pollution studies, the Bureau of Mines is cooperating with the U.S. Public Health Service in investigating the use of solids for removing sulfur dioxide in concentrations of less than 0.5 percent from combustion and waste gases. Removal of sulfur dioxide at flue-gas tempera¬tures would no longer result in the cooling of scrubbed gas, which is inherent to liquid scrubbing processes used exclusively in industry today. Results are reported of extensive investigation, using metallic oxides as absorbents, adsorbents, and oxidation catalysts at 130° and 330° C. (temperatures at which flue gas may be treated in powerplant practice). The most active absorbents tested were the oxides of manganese, cobalt, copper, and alkalized alumina; 23 to 33 grams of sulfur dioxidn were removed by 100 grams of absorbent at 130° C., while scrubbing more than 90 percent of the sulfur dioxide from a simulated flue gas, and 19 to 61 grams of sulfur dioxide were removed at 330° C. A more detailed study is reported on absorption and regeneration, using manganese oxides and alkalized alumina. Adsorption of sulfur dioxide on activated carbons and molecular sieves at elevated temperatures is considerably less efficient than removal by absorption--a maximum of 7 to 8 grams of sulfur dioxide could be removed with 100 grams of adsorbent at 130° C. A potash-promoted vanadium pentoxide is effective in converting sulfur dioxide to trioxide; complete conversion in a simulated flue gas containing 0.35 percent sulfur dioxide was obtained at 365° C. Pilot-plant and cost studies are being made by the Bureau to determine the economic feasibility of removing on an industrial scale the sulfur dioxide present in gases in low concentrations.

Jan 1, 1961

By P Lever, D Hainsworth, H Gurgenci

The ACARP Landmark initiative has created the opportunity to advance the level of automation in the coal industry by first focusing on the core production area of longwall mining. A Landmark Longwall Automation project was commenced in July 2001. The major outcome of automation using on-face observation has been divided into ten outcome areas that have been fully scoped for a three-year initial project life. A major facilitating technology has been the implementation inertial navigation system (INS) technology that can map the shearer position in 3D. A focus of the project is to deliver a system that is at least as productive as the current most productive manually controlled longwall face.

Jan 1, 2002