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By L. J. Terrill

Lateral displacement in the immediate roof beam at the Waste Isolation Pilot Plant (WIPP) is a significant factor in assessment of excavation performance for the design of ground control systems. Information on roof beam lateral displacement, expansion, fracture formation, as well as excavation convergence, is gathered using a variety of manually and remotely read instruments. Visual observations are also used when possible. This paper describes the methods used to measure lateral displacement, or offset, at the WIPP. Offset magnitudes are determined by the degree of occlusion in drillholes that intersect the offset plane. The Borehole Lateral Displacement Sensor (BLDS) was developed for installation at WIPP to monitor offset at a high degree of accuracy at a short reading frequency. Offset measurements have historically been obtained by visual estimation of borehole occlusion. Use of the BLDS will enable relationships between time dependent roof beam lateral displacement and expansion to be established in much shorter periods than is possible using visual observations. The instrument will also allow remote monitoring of roof beam displacement in areas where visual estimations are not possible. Continued monitoring of roof beam displacement, convergence, and expansion, is integral to timely and pertinent assessments of WIPP excavation performance.

Jan 1, 1996

By Meng Xiao, Peng Huang, Lizin Lan, Feng Ju, Shuai Guo

"Through changing the axial load on backfilling material compaction test to reflect different overlying strata pressure on backfilling material, the stress-strain relations in the compaction process of backfilling material under the geological condition can be obtained. Based on the characteristic of overlying strata movement in backfill mining, a model of roof thin plate is established. By introducing the stress-strain relation in compaction process into the model and using RIZT method to analyze the bending deformation of roof, the bending deflection and stress distribution can be obtained. The results show that the maximum roof subsidence and maximum tensile stress occurring at the center are 255mm and 5 MPa, respectively. Tensile fracture of roof under the geological condition of Dongping mine did not occur. The dynamic measurement results of roof in Dongping mine verify the theoretical result from the aforementioned model, thereby suggesting the roof mechanical model is reliable. The roof thin plate model based on the compaction characteristic of backfilling material in this study is of importance to research on backfill mining theories and application of backfilling material characteristics.INTRODUCTIONSolid backfilling mining (SBM) is a green mining technology in which the solid waste materials is placed into the gob to support the overlying strata and to control roof's subsidence and movement (Miao, 2012; Miao et al., 2010, 2015). SBM has been successfully used in several mines to solve many problems, including coal extraction under buildings, water bodies and railways, surface subsidence, and environmental problems. Good results have been obtained in many mines (Zhang et al., 2009). The key in the application of SBM technology is controlling strata movement. However, the critical factor influencing the controlling effect of strata movement is compaction characteristics of backfilling materials. Thus, a roof model of SBM is built based on the filling materials' compaction characteristics. A subsidence equation and the critical failure condition of roof was given and field verification was performed at Panel 15061 of Donping Mine."

Jan 1, 2016

By C. W. Parmalee

The ideal fuel for burning ceramic wares is the one that, among other characteristics, has little or no sulfur. For that reason wood was long considered the most desirable fuel but its high cost has practically eliminated its use except in regions where it is very abundant or other circumstances warrant its choice. The fuels commonly employed are natural and producer gas, oil, and coal. The last named is undoubtedly the most important, not only in this country but abroad. Occasionally anthracite is used but the larger part is bituminous. The quality of the coal used depends on the kind and the value of the products being manufactured. For some materials, such as common brick, hollow block, etc., the quality of the coal is of less importance than in the manufacture of polychrome terra cotta, pottery, porcelain, etc. It is obvious that in burning clays that contain notable amounts of pyrite, marcasite or gypsum, as is the case with many common clays, the sulfur content of the fuel is of much less importance. The permissible amount of sulfur in the coal used will depend on the kind of product being manufactured. "A good sample1 of coal commonly used in pottery ovens has something like this quantity of sulfur: total sulfur, 1.20 per cent.; sulfur in ash, 0.11 per cent.; volatile sulfur, 1.09 per cent." This is based on English pottery practice. Correspondence with a. number of leading manufacturers in this country has produced the following figures: Sanitary Ware.—(a) 1.0 per cent, maximum, (b) 0.5 per cent. Sewer Pipe.—(a) 1.2 per cent., (b) 1.1 per cent, present run, 3.0 per cent, has been used. Terra Cotta.—(a) 0.5 per cent, basis of contract, 1.0 per cent, approximate. Pottery.—1.0 per cent, contract, 1.5 per cent, probable content. Enameled Brick.—1.3 per cent, maximum, (a) and (6) designate different firms giving figures. Since a pottery kiln for sanitary ware will require about 14 tons of coal for a bum, the quantity of SO2 that will be generated from a 1-per

Jan 1, 1920

By Ray Brandon

The recent introduction of polymer geogrids for ground control purposes in underground mines allows mine operators more flexibility in choosing improved products for several applications. This is evidenced most clearly in longwall recovery operations. Since November, 1994, many mine operators have chosen Fortrac geogrid assemblies for the purpose of securing longwall recovery areas prior to shield removal. Fortrac is a lightweight, strong, and flexible polyester geogrid available in many strengths. Utilizing the "diamond" seaming method, different strengths of Fortrac geogrids are easily fastened together so stronger geogrids may be placed in the most critical areas and lighter geogrids in less critical areas.

Jan 1, 1996

By E. D. Gardner

AGAIN in 1945, the fourth year of World War 11, the American mining industry met the necessary demand made upon it for metals. Lack of labor prevented full production in some districts; maximum output, however, was maintained with the man power available. Development work and maintenance of mechanical equipment were neglected in favor of immediate production. Drafting of the younger men continued throughout the year, and the loss of personnel to war industries with higher wage rates continued up to "V-J" Day, Aug. 14. Labor shortages were more critical in 1945 than in 1944 though the man-power situation eased for some districts in the last quarter of the year. The trend in mining for the most part was to increase tons per man-shift by continued increased mechanization and refinements in methods and practices; larger equipment was installed where practicable. Labor shortages, together with the current higher wage rates, have advanced mechanization several years ahead of normal progress. The manpower shortage and the employment of inexperienced men had the effect of decreasing the average efficiency of the individual workman, but this condition was largely balanced by improved organization, greater efforts to improve labor relationship, and increased use of incentive pay systems. Safety instruction was emphasized, personnel contacts were increased, and more frequent foremen meetings were held to clarify contract agreements. Many of the large companies maintained schools to train green workmen.

Jan 1, 1946

By Davis M. Lapham

Ore bodies at Cornwall, Pennsylvania, have been mined since 1742 principally for iron from magnetite, but also for copper (in chalcopyrite), silver (in chalcopyrite), gold (in chalcopyrite), cobalt (in pyrite), sulfur, and crushed limestone aggregate. Metallization occurs as a limestone replacement above the essentially conformable, south dipping portion of a discordant saucershaped diabase sheet. Pre-Triassic and Triassic faulting have emplaced host Cambrian limestone and two Ordovician(?) hornfels units, now for the most part resting above diabase. Thermal metamorphism of carbonate-bearing country rocks largely to calc-silicates, is ubiquitous. Metasomatism, particularly of potassium, is unique to ore zones. Associated magnetite- actinolite mineralization replaces, in a preferential sequence, all earlier metamorphic and metasomatic minerals and rarely diabase chilled margin. Mineralogical (diopside, actinolite, mica, sulfides, oxides) and chemical (Fe, Cu, S, Co) zoning of the eastern ore body is focused down dip, near its western edge, along a major vertical fault through diabase. This zoning is spatially related to magnetite veins in diabase, to an ore body within diabase, and to a shear zone that probably extends through the sheet.

Jan 1, 1968

By Michael W. Lewis

The latest downturn in the world’s metal prices has forced many mining companies to focus on cost reduction and productivity improvements to remain competitive. Maintenance represents a significant part of the overall operating costs in the mining industry. A structured, proactive maintenance approach, such as reliability-centered maintenance, can achieve cost reductions and productivity improvements. Remote condition-monitoring systems are becoming commonplace because they have the potential to identify problems before failure. Detection of equipment degradation before failure will enable repairs to be scheduled, thereby reducing costs and interruptions to production. The mining industry is in the midst of uncertain times. Decreasing commodity prices, demand, head grade and capital availability along with increasing environmental requirements have put pressure on mining companies to significantly reduce costs to maintain short- and long-term viability. Corporations are looking at expansion, merger/consolidation and financial/hedging programs to achieve these cost reductions. Mines are reducing costs by eliminating all but essential expenditures, increasing production levels, reducing overtime and investing in new technologies.

Jan 1, 2000

By L. R. Fyffe, D. R. Lentz, S. H. Mcclenaghan

"Abstract - The Eel River area in the southwestern Miramichi terrane of New Brunswick contains a complete calc-alkaline suite of volcanic rocks that are interlayered with intervals of sedimentary and polylithic fragmental rocks, and are overlain by a thick sedimentary sequence. This package, collectively referred to as the Meductic Group, was deposited in a submerged volcanic arc setting interpreted to be part of the Popelogan arc. Rifting of this arc led to the development of the Tetagouche-Exploits back-arc basin, and formation of volcanogenic massive sulfide deposits in bimodal volcanic rocks of the Bathurst Mining Camp in the northeastern Miramichi Terrane. Unlike the Bathurst Mining Camp, volcanic rocks in the southeastern Miramichi Highlands form a continuous calc-alkaline suite characterized by increasing Zr/TiO2 with increasing SiO2, in part resulting from progressive coupled assimilation and fractional crystallization of nested magma systems. Slumping of semi-consolidated volcanic and sedimentary rocks in topographically unstable areas resulted in numerous slumps and debris flows that are preserved throughout the Eel River area. In the early 1990s, the discovery of a large sulfide clast in a road cut along the Benton road sparked interest in the volcanogenic massive sulfide potential of the Eel River area. Subsequent drilling intersected smaller fragments, one clast of which graded 16.7% Zn, 5.6% Pb, 90 ppm Ag, and 220 ppb Au. The intersection of thin lenses of stratiform sulfides in another drillhole indicates favorable conditions for the preservation of massive sulfides. Their subsequent incorporation into synvolcanic debris flows resulted in the transport and deposition of sulfide clasts from hydrothermal vents to more distal locations. Similar to the Buchans deposits of Newfoundland, tracing these debris flows back to their source would be beneficial from an exploration perspective. Approximately 15 km to the southwest of the Eel River area, gold-bearing base metal sulfide clasts (11.1% Zn, 6.13% Pb, 0.19% Cu, 108 ppm Ag, and 1100 ppb Au) occur within intermediate-composition volcanic rocks at Monument Brook in eastern Maine. Sommaire - Le secteur d’Eel River dans le sud-ouest de la terrane de Miramichi au Nouveau Brunswick contient une séquence complète de roches volcaniques calco-alcalines interstratifiées avec des roches sédimentaires et fragmentaires polylithologiques, sous une épaisse couverture sédimentaire. Cet assemblage constitue le Groupe de Meductic, et a été déposé dans un environnement d’arc insulaire interprété comme une partie de l’arc de Popelogan. Le rifting de cet arc à mené au développement du bassin d’arrière-arc de Tetagouche-Exploits, et à la formation de gisements de sulfures massifs volcanogènes dans les roches volcaniques bimodales du Camp Minier de Bathurst dans le nord-est de la terrane de Miramichi. Contrairement au Camp Minier de Bathurst, les roches volcaniques des hautes terres du sud-est de Miramichi constituent une suite calco-alcaline continue caractérisée par un accroissement du rapport Zr/TiO2 à des valeurs croissantes de SiO2, résultant en partie de l’assimilation progressive et de la cristallisation fractionnée de systèmes magmatiques superposés. L’effondrement de roches volcaniques et sédimentaires semi-consolidées dans des secteurs topographiquement instables est à l’origine des nombreux slumps et coulées de débris qui sont préservés dans le secteur d’Eel River. Au début des années 1990, la découverte d’un large claste de sulfures le long de la route Benton provoqué un intérêt pour le potentiel en gisements de sulfures massifs volcanogènes dans les secteur d’Eel River. Des forages ont par la suite recoupé des fragments plus petits, dont un claste qui a retourné des teneurs de 16.7% Zn, 5.6% Pb, 90 ppm Ag et 220 ppb Au. Le recoupement de minces lentilles de sulfures stratiformes dans un autre forage indique des conditions propices à la préservation des sulfures massifs."

Jan 1, 2006

By D. H. Horswill

The Red Dog Mine is the world’s largest zinc mine. It is located 145 km (90 miles) north of the Arctic Circle in northwest Alaska on lands owned by the Inupiat Eskimo organization called the Northwest Alaskan Native Association (NANA) Development Corp. NANA acquired surface and subsurface title to this resource as part of its settlement lands under the Alaska Native Claims Settlement Act. In 1982, NANA entered into a lease agreement with Cominco. Cominco is an international mining company focused on zinc. It built and operates the Red Dog Mine. NANA’s principle objective in the development of the mine was to have it contribute to the development of sustainable communities within their traditional region. This meant creating job opportunities in a modern economy while preserving the traditional subsistence lifestyles. Preservation of their culture, language and traditions are as important to the NANA people today as they were in the past.

Jan 1, 2000

By Howard J. Haselhuhn

"The effectiveness of reagent adsorption onto hematite ore particle surfaces is critical during beneficiation to promote effective selective flocculation and dispersion and increase iron oxide recovery. The relationship between aqueous calcium in the process water and the effectiveness of common iron ore dispersants has never before been studied. The nature of common dispersants was studied in the presence and absence of calcium in the process water. The settling behavior of hematite-rich iron ore at pH 11 was assessed in the presence of calcium and inorganic dispersants: sodium silicate, sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP) and organic dispersant ethylenediamenetetraacetic acid (EDTA). It was found that inorganic dispersants are ineffective at a pH of 11 without activating the surface sites of the ore particles with calcium. Organic dispersants, however, were found to be effective with and without surface site activation.IntroductionThe United States produced 54 million metric tons of concentrated iron ore in 2011 (Jorgenson, 2013). Over 8 Mt were produced using a process known as selective flocculation and dispersion (CCI, 2011). The grade of this ore is slowly depleting, making it imperative that processing efficiency improves. To increase processing efficiency, a complete understanding of the effects of chemical reagents in the process must be acquired. This process relies heavily on dispersants to disperse iron oxides from gangue minerals in settling processes. The mechanism that these dispersants use to disperse the ore and its relationship to calcium in the process water has never been studied. The following extended abstract summarizes the relationship between aqueous calcium in process water and the effectiveness of common iron ore dispersants at dispersing hydrated hematite ore. These tests were carried out at a pH of 11, as this is a typical pH used to ensure dispersion in selective flocculation and dispersion processes."

Jan 1, 2015

By A Scrase, J Brereton

The Latrobe Valley is located approximately 150 kms east of Melbourne. Within a very small area there are 3 large brown coalmines and associated power stations, 3 large towns, and numerous smaller towns in the vicinity. The mines have been generating power for Melbourne and surrounds for the last 100 years, with two of the mines being owned and operated by the Victorian Government (State Electricity Commission of Victoria) prior to privatisation in the 1990s. All three mines were privatised with the expectation that the mine voids would be filled with water to become pit lakes, as the final landform/rehabilitation solution (Hazelwood Mine Fire Inquiry, Teague and Catford, 2016). It could be argued that until relatively recently, this was largely expected, by government and industry, to be the rehabilitation solution for managing the two key risks associated with the sites:  The geotechnical stability of the mine pits.  The prevention of fire – through covering coal batters with water. Transitioning away from mining economies requires collaborative, regional, innovative thinking with a multitude of stakeholders, from a wide range of government departments, industry, First Nations people and broader community. Closure planning and rehabilitation activities require a range of skills and experience, such as, closure planning, various scientific and engineering disciplines (pit water quality modelling, geochemical modelling, cover design, landform design, contaminated site etc), civil engineering, demolition etc. Some of these skills are similar, such as financial modelling, stakeholder engagement, contract and project management. But the majority are different to those required during the operational phase of a mine. These closure skills can also be lacking within government, with Departments more familiar with monitoring and compliance activities associated with operational facilities. Some key aspects that appear to be critical to planned successful closure are:  Collaborative regional and localised planning, with industry, government, community, First Nations and other industry, business leaders and entrepreneurs all involved in providing a smooth transition away from mining.  Well-defined and known regulatory pathways to achieve mine licence relinquishment assists in encouraging investment.  Appropriately skilled and experienced government and industry personnel.  Mining companies, who are committed to closure planning and provisioning from the earliest point in project planning.  Mine employees who are appropriately skilled and experienced in mine closure planning and implementation with access to all the relevant technical expertise required for the project. Areas like the Ruhr Valley in Germany provide good some examples of smooth processes that facilitate mine economies transition into new economies (World Resources Institute (WRI), 2021).

Aug 2, 2023

By Shawn Boltz, Erik Westman, Derrick Chambers, Xingdong Zhaoa, Qiankun Zhua

Microseismic passive velocity tomography is becoming an effective technology for large-scale mining-induced stress monitoring in underground mines, especially in the field of early warning of mining-induced hazards. Aiming at the problems of missing low-magnitude events in traditional microseismic monitoring, as well as the potential to increase the resolution of the tomograms in both time and space, a microseismic passive velocity tomography analysis method based on the template matching method was proposed. First, the template matching method was used to pick microseismic events. Then, the probabilistic, non-linear, global-search earthquake location method was used to locate the events and calculate travel time and travel distance. Finally, the fast-marching method was used to carry out passive velocity tomography analysis to image the movement of the abutment stress associated with the longwall. The results show that the selected templates can identify more microseismic events than the traditional microseismic analysis, and the variation trend of events in each day is consistent with the data from the traditional analysis. Using microseismic event locations, travel times and travel distance can effectively complete microseismic passive velocity tomography analysis in each day during the study period and can effectively identify the forward and side abutment stress zones of that longwall panel. This study provides a reference for the identification of mine-induced high stress zones, which has implications for hazard identification and mitigation, with increased resolution of the tomograms in time and space.

Jun 25, 2024

By Paul Gilmour

"The principal role of the geologist is to recognize the existence of phenomena before trying to explain them" - B.M. Keilau, 1825; A. Holmes, 1965 Some important groups of mineral deposits in the layered rocks of orogenic belts or greenstone belts occur in horizons characterized by the presence of exceptional amounts of silica, iron and carbon, with more or less significant amounts of manganese. Generally, the rocks involved are well banded. In practice, these five physical features - four compositional and one geometric - are found with many lithological guises. Iron formation, in the full, modern sense of the term (James, 1954), quartzite, ferruginous quartzite, chert, jasper, "tetsusekiei" (Horikoshi, 1969), tuffaceous jasper ("purple porphyry" - Anderson and Creasey, 1958, p. 36), ferruginous or graphitic shale, argillite, slate or schist, and hematitic tuff are but a few of the more familiar of the names that have been assigned to these rocks. Widely acknowledged and well-documented examples of metallic deposits found in such sediments include concentrations of iron and manganese and stratabound, polymetallic, massive pyritic sulfides. Less familiar examples include occurrences of asbestos (Miles, 1953; and Coetzee, et al., 1976), antimony (Coetzee, 1976), and perhaps stratabound deposits of Au-Cu-U-W-etc., such as Aitik in Sweden (Mining Magazine, 1975; and Nilsson, 1979) and Olympic Dam in South Australia (Roberts and Hudson, 1983). The case of gold is intriguing. An association between gold and iron formation has been identified at several famous deposits and districts, such as Yellowknife, N.W.T. (Morton, 1979), Homestake, S. Dak. (Sawkins and Rye, 1974), Vubachikwe, Zimbabwe (Fripp, 1976) and the Barberton district, R.S.A. (Hammerbeck, 1976). Yet a critical reading reveals the existence of many other hitherto unsuspected examples. The purpose of this note is to draw attention to that omission and the apparent explanation for it. It is not hard to detect the two most probable reasons for the discrepancy between reality and the record.Most occurrences of gold are associated, not with the familiar banded iron formation or interbedded magnetite and chert (technically, the magnetite-banded variety of the oxide facies), but with the enigmatic carbonate, sulfide and silicate facies of iron formation and/or with rocks evidently related to iron formation. All too commonly, the unfamiliar facies of iron formation have been identified by field and mine geologists and not a few researchers as products of regional metamorphism and hydrothermal alteration, as mafic igneous rocks, or as conventional sediments, ie., without regard to their intrinsically ferruginous nature. The justification for these two complementary assertions is largely to be found in the recognition of a characteristic suite of metals and minerals in gold deposits known to be associated with iron formations. Although, from a geological standpoint, a lithological association is more important than a mineralogical assemblage, the latter is the more likely of the two to be diagnostic. This arises from the different natures of mineral and rock classifications, The identification of a mineral or an element is a matter of fact. Owing to the genetic component inseparable from petrographic nomenclature, viz., "igneous": a rock (believed to have been) derived from a melt, the identification of rocks depends on inferences or conclusions about their mode of formation - conclusions that are commonly debatable and, all too often, involve subjective judgements. This is especially prone to be true, if - as at many of the gold occurrences in question - the host rocks have been metamorphosed and/or "altered". In the notes that follow greater weight has accordingly been assigned to elemental and mineralogical than to host rock composition. In other words, if, in a given gold occurrence, the suite of metals and minerals present conforms to the standards of the subject class, whereas the names assigned to host rocks do not, the latter will be viewed as suspect.

Jan 1, 1985

Gippsland has perhaps the most colourful history of exploration of any area in Australia. Hydrocarbons were first discovered in the Gippsland Basin in 1924 when a water well at Lakes Entrance encountered oil and gas shows. In 1942, the Commonwealth and Victorian Governments, in an effort to supplement a wartime oil shortage, sank a shaft near this well and produced 8000 barrels of low gravity oil up to 1956, when the field was abandoned. A total of 64 shallow wells had been drilled in the Lakes Entrance area by that time. Elsewhere in the onshore Gippsland Basin, 30 wells were drilled from 1925 to 1941. In 1960 BHP Ltd was granted an exploration permit covering much of the offshore area of the Gippsland Basin. Esso Australia Ltd joined BHP in 1964 and drilled the Barracouta-1 gas discovery in 1965. Since then over 100 exploration and appraisal wells have been drilled in the basin resulting in the discovery to date of some 3.6 billion barrels of recoverable oil and 8.8 trillion cubic feet of recoverable gas (Current remaining recoverable reserves are 906 million barrels of oil and 5.7 TCF of gas). Exploration in the offshore areas is actively continuing today and new discoveries are still being made.

Jan 1, 1992

By Moussa Wone

The Washington, DC Water and Sewer Authority (WASA) has implemented facility planning for the Anacostia River Projects portion of a program to bring its Combined Sewer System (CSO) into compliance with federal water quality regulations by 2025. The program includes approximately 19 kilometers (12 miles) of deep CSO storage/conveyance and flood relief soft ground tunnels, construction, vortex drop, overflow, maintenance and air release shafts, as well as near surface diversion structures and conveyances. The Project encompasses major technical and non-technical challenges including completion under a federal consent decree schedule, construction within the confines of heavily developed urban areas, difficult ground conditions, major infrastructure crossings, and close coordination with several major public agencies. This paper discusses the planning stage considerations related to the geotechnical investigation program, discusses obstructions that influenced alignment selection, and provides two examples of preliminary estimates of settlement induced ground movement due to the tunnel and shaft construction.

Jan 1, 2008

By L. F. Elkins

In 1946 Littlefield, Gray and Godbold published a thorough geologic description of the West Edmond Hunton Lime reservoir, located in Central Oklahoma, and discussion of its early performance.l They stressed implications of the nature of the reservoir rock on performance to be expected with production both by natural means and by pressure maintenance with gas injection. The essence of their analysis was that presence of an extensive interconnected system of fractures and solution channels constituting about 10 percent of the total reservoir void space in otherwise very low permeability reservoir rock would result in severe channeling of naturally encroaching water or injected gas through the fractures with little or no benefit to ultimate recovery of oil. Considerations were in progress to unitize the reservoir for pressure maintenance by gas injection. Some other engineers involved in the project had considerably different opinions at the time regarding continuity of fractures and regarding effects of such fractures on performance. The field was unitized Oct. 1, 1947. Subsequently, pilot gas injection tests were conducted in four areas of the field; large scale waterflooding was conducted in two parts of the field in the Bois d'Arc or Upper Hunton; and pilot waterflooding was conducted in the Chimney Hill or Lower Hunton. Full scale water-flooding is now in progress in the Chimney Hill section where it is oil productive. The primary purpose of this paper is to divine some of the secrets of this reservoir through analysis of all aspects of its performance, with the hope that it will be of help to engineers and operators in developing and operating other low permeability fractured reservoirs. In part, this considers variance of actual performance from some widely used conventional reservoir engineering assumptions. For brevity, other aspects of unit operation and its benefits to the owners are not discussed. Oil and Gas in Place For unit participation, net pay in the Bois #Arc defined by the gross SP anomaly on electric logs totalled 2,100,000 acre-ft in the 30,000-acre reservoir. Development of West Edmond predated modem logging techniques that now would be used to determine "net" or "productive" pay. In Fig. 1 this log pick is compared with detailed core analysis and core descripfion by Littlefield et a1.l for one well identified as A on the index map in Fig. 2. Not all of the gross Bois #Arc section had oil staining, but all cores with measureable intergranular permeability were stained. (The committee selection of the Bois d'Arc SP interval also includes the Frisco section as identified from cores by Littlefield.) The Bois d'Arc is oil productive throughout the entire 600-ft monoclinal accumulation from the eastern upstructure erosional pinchout to the west-side oil-water contact. (See Littlefield et al.l and McGee and Jenkins for geologic detail.)

Jan 1, 1970

By B Mobilio, M Secheny, J Rachocki, G B. Sharrock, A Jäger, J L. Lett, I Brunton, G W. Capes

Establishment of the Cadia East Panel Cave Stage One (PC1S1) commenced with the firing of the first bell in early 2011. Production began with the completion of the undercut in May 2014. PC1S1 used a post-undercut composed of 114 drawbells covering a footprint area of 73 438 m². The extraction level is located at a depth of 1200 m below the surface and is based on a 32 × 20 m El Teniente layout. Cave establishment required the construction of multiple conveyor drifts, a large-capacity jaw-gyratory crusher and ancillary ventilation and pumping infrastructure. Preconditioning via hydraulic fracturing and blasting was implemented at various locations of the cave block height. This paper presents an overview of the key learnings from the commencement of undercutting to surface breakthrough, including rock mass classification and modelling, stress measurements, preconditioning, numerical modelling and cave monitoring.CITATION:Lett, J L, Brunton, I, Capes, G W, Jäger, A, Mobilio, B, Rachocki, J, Sharrock, G B and Secheny, M, 2016. Undercutting to surface breakthrough – Cadia East panel cave (stage 1), in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 65–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By L. Sahu, S. Bhattacharya, S. Dey

"An ideal procedure to determine the limits of flotation-based separation, as is the case with washability analysis for density separation, does not exist. Therefore, a procedure called release analysis, considered to be the counterpart of the washability process in density separation, was developed to evaluate the flotation characteristics of coal fines. Since flotation is a complex process it is necessary to know the maximum recoverable yield that could be achieved at a target ash level and what could be obtained by release analysis. Due to a number of limitations in the initial procedures, modifications were recommended by various researchers to generate an optimum separation curve. This paper presents a review of, and a discussion on, the chronological evolution of release analysis methodology over the decades. Notwithstanding the availability of a standardized release analysis procedure, such as BS 7530, the paper highlights the critical parameters involved in the procedures, such as coal type, feed characteristics, choice of reagents and dosage, operator bias, and design features of the flotation cell IntroductionCoal is a heterogeneous substance consisting of various combustible constituents (macerals) and associated mineral matter. The kind and abundance of the various macerals present in the coal, such as vitrinite, semivitrinite, exinite, and inertinite, determine the type of coal. As macerals are formed by biological degradation of different parts of the plant material, they have different properties based on their original composition. Coal cleaning processes are dependent on the differences in physical properties between the coal components (the macerals) and also between the macerals and the mineral matter. Thus the cleaning characteristics of the coal might vary from one type to the next. The cleaning processes influence the distribution and the concentration of macerals in the various size and density fractions of the cleaned product."

Jun 1, 2019

By A Dunne, R Kruger, H Coleman, P G. Laurens

External and internal challenges in mining are increasing the difficulty and complexity of operating mines. The external mining environment has a big impact on mining operations and is driving the focus on safety, sustainable mining, green issues, profitability and productivity. There is a very high emphasis on ‘reducing cost to improve’, lower mining and beneficiation costs by eliminating waste/inefficiencies (reduce people, use less consumables, multiskilling, etc). The internal mining environment is getting tougher to operate in, with the deposits being more difficult to mine, more difficult to manage due to external pressure along with issues associated with maintaining quality, etc.Technological and environmental developments too numerous to mention, mean that cost control models, reduction in human resource numbers, as well as other drastic measures to curtail expenditure and increase profitability have become part of everyday business. The capability to manage the mining environment in a systemic manner has been lacking and this increases the pressure for performance on those individuals operating and managing mines.Working smarter has become crucial to ensure that businesses optimise the use of their resources, become more safety conscious, more productive and remain cost-effective, while recognising the importance of sustainable mining now and in the future. The logic of determining and managing to the capability of the mining value chain will be examined and the underlying assumptions or beliefs guiding behaviour and decision-making will be highlighted.In order to identify the obstacles in the mining value chain that hinder achievement of its full potential, the following questions have to be asked:What are the factors that influence the performance of a mining value chain?What is the design capacity of the mine?How can the inherent flow and value capacity of a mine be determined?What types of solutions will allow a mine to operate at its inherent flow and value capacity?This article will discuss the way we plan, measure, assess and manage the mine value chain, by addressing the following factors:balanced capacity versus flow and value capacity designthe use of averagingoptimising individual components in a value chain versus optimising the whole value chain.Optimising flow and value through the mining value chain is one of the three pillars of Mineral Resource Throughput Management (MR™). MR™ is an entrenched and academically supported philosophy that has been successfully applied in the past decade in various mines throughout the world by EXXPLEO, a mining and beneficiation consulting company. EXXPLEO has partnered with HCL (a global IT company) to embed the MR™ philosophy, methodology and toolsets into a formal software product called Synchronised Digital Mining (SDM). The SDM system will provide mining companies with a sustainable platform to effectively apply the MR™ principles and toolsets effectively across all operations targeting increased productivity, efficiency and profitability without having to train operations and management staff into expert MR™ practitioners to successfully achieve the desired results.CITATION:Dunne, A, Laurens, P G, Kruger, R and Coleman, H, 2015. Optimising flow in the mining value chain, in Proceedings Iron Ore 2015, pp 437–442 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Geology grads mine heated job market Salaries up 44 per cent in three years ?[Geology student] passed up a $100,000-a-year job at a mining company last December when he finished his degree in geology. The 24-year-old Canadian said he?s confident he?ll get a better offer.? Rob Delaney and Stewart Bailey, Calgary Herald, Published: Saturday, March 15, 2008 Massive shortages across the mining industry > Trades and operators are a large component > Technical people are equally hard to find > Students are in an excellent positions to secure exciting jobs > Experience is at a premium. Why?

May 1, 2008