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Planning the primary development of a mineral deposit usually is done only once during the life of a mine. As a consequence, not optimizing the primary development of a mineral deposit can cause disadvantages over the whole life of a mine and can lead to higher costs. As a contribution to an improved primary development design procedure beyond the already existing work a study of the identification and quantification of the influence of parameters on primary development based on operational data from working mining operations has been completed. Based upon such a quantification of the influence of parameters a sequenced decision model was developed, that enables to develop an initial concept for the design of the accesses from the surface based upon a few critical parameters. Such a model will not replace detailed planning work within a feasibility study, but it is intended to reduce the amount of planning efforts at an early project stage through providing information what are most likely economic solutions, based on simple rules.

Jan 1, 1997

By Daniel W. H. Su

A nearly 305-m- (1,000-ft-) wide sandstone channel was projected to run through the mid panel area of a 457-m- (1,500-ft-) wide longwall panel in a southwestern Pennsylvania coal mine. This sandstone channel was known to cause serious longwallface roof control problems in the mine?s B-panel area in 1998 and 1999; and most recently, it induced many large face cavities and caused a substantial production delay in the preceding panel. For the two B panels mined in 1998 and 1999, hydraulic fracturing of the massive sandstone was conducted to facilitate better caving, thus relieving cantilever compressive stress at the longwall face. Vastly improved longwall face condition was observed and four weeks of mining delay due to bad roof conditions were eliminated. The implementation of the hydraulic fracturing technique, results of underground observation and measurement, and results of numerical modeling were summarized in a paper presented in the 20th International Conference on Ground Control (Su et al., 2001). This article is a summary of the activities that took place during a four-month period (October 2011 through February 2012) at a Consol Energy longwall mine southwestern Pennsylvania to improve face conditions and safety of underground personnel during mining of the 457-m- (1,500-ft-) wide longwall panel. The elevated concern for safety was driven by adverse face conditions encountered while mining the preceding longwall panel. Many of the problems were attributed to a thick and massive sandstone channel. A joint task force consisting of coal operations engineering, Pennsylvania operations engineering and CNX Gas personnel was formed in August 2011, which recommended drilling four hydraulic fracturing holes along the center axis of the sandstone channel to reduce pressure and improve face conditions at the longwall face. To further provide detailed monitoring of the longwall face and to evaluate the effectiveness of the hydraulic fracturing program, the Longwall Visual Analysis (LVA) software (Hoyer, 2011) was installed in early December 2011 to track the face pressure and c

Jun 1, 2013

By Paul S. Goodman

This report examines the effectiveness of bonus plans in the coal industry. The analysis uses theoretical, literature review and empirical approaches to determine the impact of bonus plans on safety and productivity in underground coal mines. The basic finding is that the modal bonus plan in underground coal mining does not have a major impact on productivity and safety indicators. The design of the plan, or organizational factors, and the process of introducing the plan all contribute to its relative ineffectiveness. Strategies and options for designing effective plans are presented.

Jan 1, 1987

By W. G. Freeman

This study provides recommendations for improved safety in underground blasting procedures based on in-mine observations of blasting practices in 30 underground metal, non-metal, and coal mines, and the analysis of blasting accidents since 1970 and existing state and federal regulations pertaining to the storage and use of explosives. Results of these analyses and observations indicate that 1) blasting accidents have declined but are an important contributor to the hazards of underground mining; 2) existing regulations are essentially adequate; 3) greater emphases should be placed on human errors and unsafe practices and the enforcement of existing regulations; and 4) future revisions of these regulations and standards should be organized, and their intent coordinated to eliminate ambiguities.

Jan 1, 1980

By R Kjar

Globally, it is anticipated that the mineral sands industry will enter a period of short supply. Demand for both titanium dioxide and zircon is forecast to continue increasing, with new projects needed to come on-stream to fill the supply gap. Victoria is well placed under this scenario as a source due to the high quality of its mineral assemblage, its excellent resource grade and the globally significant size of its mineral sands resources.Australia’s mineral sands rich Murray Basin remains under-developed, especially at its extensive Victorian margins. Development to date has not progressed adequately for the reasons of technology difficulty, history of competition with other jurisdictions and the absence of a platform that requires development as a consideration for security of tenure. Victoria’s mineral sands potential is not just about the Murray Basin, in addition, there have been discoveries in the Gippsland Basin and prospective sites in the Gippsland Basin remain under-explored. Key problems included the lack of available ground for potential developers and the intellectual property of solutions to technological problems associated with the fine grained mineral deposits belonging to a previous developer (with patents now expired).As such, the timing is right to re-visit the potential of the Murray Basin as a site for long-term development with high returns based on current and predicted prices.In order to understand why Victoria’s earth resources in general, and mineral sands in particular, remain under-explored and undeveloped, the Department of Primary Industries initiated an internal review of its role in encouraging and supporting investment in the earth resources sector.As a result, the Victorian Government has committed to taking action to encourage effective ground turnover and acknowledges that a new focus on engagement with industry is needed to bring new investment to the State. The revision of the Mineral Resources (Sustainable Development) Act 1990 provides an opportunity for the government to better align its legislative processes with industry project lifecycles and facilitate access to valuable resources that currently remain undeveloped.Victoria has a track record in assisting projects reach development stage. Iluka currently has two operations in the State in addition to its mineral separation plant that is capable of processing HMC from its South Australian operations. Iluka is expected to ramp up its Murray Basin Stage 2 operations with the WRP mine scheduled to come on line in early 2012. Meanwhile, Astron is actively seeking partners for its Donald Mineral Sands project. The project is becoming increasingly attractive given the recent price hike in zircon; Astron has access to an estimated five to 6 Mt of zircon in its Donald WIM 250 deposit.Given its substantial and valuable mineral sands endowments, the State of Victoria should sensibly be the centre of future investment in project development. However, as previously mentioned this is currently not the case. The Government is therefore committed to implementing new measures that protect security of tenure but ensure that genuine companies can access endowments where they have a clear intent to work those resources.

Oct 5, 2011

By Jr. Koch

As a means of investigating the distribution and variability of gold in ore from the Homestake mine, Lead, S. Dak., the Bureau of Mines performed a designed sampling experiment, and assay results were statistically interpreted. Fifty-six feet of diamond-drill core from five boreholes was sawed into l-inch-long cylinders, which were sampled randomly and were assayed. Analyses of variance of the assay results were used to compare and assess the different types of variation: within drill holes, among paired drill holes, among unpaired drill holes, and among furnace runs. The extreme variability in gold mineralization found is the natural variability on the smallest scale that can be detected by fire assay; most of the variability is associated with among-feet rather than within-feet sample intervals. Because of the extreme variability, one-half of the gold is in 3 percent of the samples.

Jan 1, 1967

By C. W. Davis

This is the first of a series of papers being; prepared as the work progresses in a study of the hydrometallurgy of manganese. The investigation is being made in an endeavor to make possible the utilization of lour-grade domestic manganese ores. The value of a hydrometallurgical process for manganese depends on the present and future uses for manganese products.

Jan 1, 1930

By Brosnan J. G

Simcoa Operations is the only silicon smelter in the region and since the plant was commissioned in late-1989, has progressed from supplying silicon metal to the secondary aluminium market to the current position of supplying in excess of 90 per cent of its production to the high quality chemical and primary aluminium markets. This position has been achieved through the unique advantage which Simcoa has developed within the industry, namely raw materials, people and Simcoa's ability to adopt and use modern technology. A quality culture was instilled into the workforce prior to commissioning which ultimately led to AS3902 qualification in 1992. Simcoa has continued its quality drive through the formation of 'Simcoa's Quality Leadership Process' which is planned to make Simcoa the best silicon producer in the world.

Jan 1, 1995

By D. G. Almond

Nkomati Nickel Mine in South Africa processes one of the world?s hardest ores in a 375k TPM autogenous grinding circuit. The plant employs an unconventional processing circuit, comprising a primary autogenous mill (AG or FAG) and pebble crushing circuit followed by a secondary hybrid pebble/ball mill and classification cyclone cluster. Advanced Process Control (APC) or Expert Control is now generally accepted as an advantage in most modern high capacity concentrator grinding circuits. This paper reviews the installation of model predictive control at Nkomati and examines the results and benefits of installation in an autogenous mill during plant ramp-up. The paper also demonstrates how predefining process control objectives together with good plant and supplier cooperation can achieve a robust and reliable APC implementation on a very short site program. The results conclusively demonstrate operational and economic benefits during circuit operation with the advanced process control system ON. Production performance and circuit stability were significantly better than during manual control.

Jan 1, 2012

These proceedings consist of papers presented at two Bureau of Mines Technology Transfer Seminars in early 1980 for the purpose of disseminating recent advances in mining technology related to surface coal mining reclamation.

Jan 1, 1980

By Suresh K. Bhatt, Christopher Mark

Fatalities caused by highwall/spoil bank failure in the surface mines, coal and non-metal, increased to an alarming rate of seven during 1999. To determine the causes of slope failure and successful mining practices, the National Institute for Occupational Health and Safety undertook a study. The study included: 1.A review of accident statistics; 2.A review of Federal and state mining laws pertaining to surface mining; 3.A literature review, and; 4.Mine visits. The study emphasized surface mines in the states of West Virginia, Ohio, and Pennsylvania. The review of a decade’s accident statistics using the mine Safety and Health Administration’s (MSHA) database showed that approximately 40% of all ground control related incidents reported to MSHA occurred in just four eastern states: Kentucky, West Virginia, Pennsylvania, and Ohio. The comprehensive literature search provided a historical perspective of highwall stability issues. Eleven mines we visited to obtain data on their mining practice or design. Commodities included coal, sandstone, and limestone. Based on the visits, five case studies were developed to represent typical mining methods and effective ground control practices used in eastern surface mines. Benching was found to be a common technique to reduce the overall highwall slope angle. Decking in the softer zones, such as shale, proved useful in controlling damage due to blasting.

By A. Eccles

Phase designs are the foundation upon which all open pit mine sequence optimizations and budgets should be built. Unfortunately, at times, mine engineers skip the step of developing realistic pit phase designs - designs that include access ramps and mineable widths. Without mineable phase designs, their optimized schedules are based on theoretical pit shells or ?quick-and-dirty? plans with no ramps. The output from such optimizations is almost always overly optimistic. Without mineable designs, the production estimates are misleading, because they overestimate ore, and underestimate waste stripping requirements. Worse yet, when plans are not based on realistic phase designs, they can point to exactly the wrong decision in feasibility studies (i.e. ?go? when it should be ?no-go?). This paper discusses the importance and features of good pit phase design, and demonstrates the pitfalls of relying on optimized production sequences that are not based on properly designed pit phases.

Feb 27, 2013

By Grant R. Brown

The report provides guidance for determining those environmental impacts associated with the surface mining of steeply pitching coal seams. In addition to the environmental impacts, four additional issues are addressed, namely (1) Time and motion studies of those coal mining systems employed in mining seams which pitch in excess of 250, (2) Assessment of those mining techniques, (3) Development of rationale for the mining methods employed, (4) Identification of the reclamation practices and determine whether these practices were in compliance with appropriate Federal and State regulations. Five surface mines located in three geologically distinct basins of the United States were analyzed during the period of August through November 1979. The three basins include the Hanna Basin of Wyoming, the North Park Basin of Colorado and the Southern Anthracite Field of Pennsylvania.

Jan 1, 1980

By George L. Wilhelm

Timber support of mine openings continues to be an effective system for ground support, due to its avail¬ability, flexibility, and ease of installation. Timber support of mine openings as a primary method to support loose rock has been replaced to a large extent by rockbolting and by filling systems. How¬ever, the many designs of square-set timber and varia¬tions of crib and stull support that have been developed to suit many stope configurations have proven reliable over many years of application. Integrated in modern excavation and stoping methods, timber remains an im¬portant ground support material for today's mines. ADVANTAGES AND DISADVANTAGES OF TIMBER SYSTEMS Timber, when used as a part of the total support system, is recognized for its unique support properties. More than a cover to prevent minor falls of ground, timber systems have been carefully designed to provide adequate support with sufficient compressive qualities to achieve a safe working environment in extremely diffi¬cult ground conditions. In some cases, a timber support method is designed to yield while retaining its protec¬tive support qualities. Little or no initial investment in equipment or plant is required for incorporating timber into the mining support system. Low cost cutoff saws and portable chain saws are sufficient equipment for effective use of dimen¬sioned (sawed) or round (stull) timber support. Until recently, small sawmills of various complexity were com¬mon at mine surface plants. Sawmills at the mine sites have generally been replaced by timber vendors' mills. Suppliers have been able to use efficient cutting and lumber handling methods to reduce the cost of mine timbers. Most suppliers will package dimensioned mine timber into bundles that are suitable for handling down mine shafts and on level conveyances. The principal disadvantage of timber as a support method is higher material cost and labor cost associated with its labor-intensive installation. Furthermore, stand¬ing timber reserves of mine quality wood are in short supply in some areas, and heavy competition exists for alternative uses of the timber supplies. Vendors are reluctant to supply large cross section dimension tim¬bers relatively free of defects. Some mine operations require 4.8-m (16-ft) lengths of firm timber over 0.09 m2 (144 sq in.) in section and these are difficult to obtain in large quantities. APPLICATION OF TIMBER FOR MINE SUPPORTS Timber used in mine support has been cut from many species of trees. A firm hardwood with physical properties similar to western Douglas fir has been pre¬ferred in the US. Other harder and softer woods, how¬ever, have been used when readily available or where the specific strength or crushing quality of the wood is a desired specification of the support system design. Hard¬ wood, commonly oak, has been used where maximum crushing resistance is required. Mahogany and fir are widely used for shaft guide timber. Normally, timber is used with its core axis parallel to the long axis of the timber dimension. However, in some cases, it is placed normal to its core in a "butt" log position, so as to provide maximum resistance to abrasion of the ore passage adjacent to the cut end of the block. By selective placement of timber block¬ing, controlled resistance to ground closure can be achieved which will prevent early failure of primary sup¬port members of the timber structure. Timber is widely used in modern mining operations as a construction member for chute-lip support. These designs are tailored to each operation to conform to the dimensions of the haulage equipment being used. As a construction material, wood requires none of the spe¬cial equipment necessary for placement of concrete or steel support. Placement of these alternate support ma¬terials requires carefully dimensioned and engineered excavation for their installation. Wood can be easily sawed to fit on location. The successful use of timber in heavy ground de¬pends on the careful and accurate placement of block¬ing and bracing to achieve the controlled yielding re¬sistance needed to support the mine opening. Similarly, frequency, size, and placement of top and bottom block¬ing stulls in flat-bedded deposits are carefully determined to provide adequate support at the mining face. Con¬trolled caving through failure of the stulls may be required as the scope retreats from the earlier mined-out sections. The support program must achieve both of these dimensionless qualities by specification of stull frequency and size. The utility of the square set-system of ground sup¬port and timber support is described in Chap. 2, re¬printed from US Bureau of Mines Information Circular 6691. Four examples of effective use of timber for support of stoping and other mine openings are pre¬sented in other chapters in this section. The Gilman mine's use of Mitchell slice stoping described in Chap. 3 is an early modification of the square-set mining system. This application proved reli¬able for heavy ground and overcame some of the dis¬advantages of conventional square-set timber. Chap. 4 describes the Burgin mine's use of timber with other reinforcement material. This combination of materials achieved high strength and control with yielding com¬ponent members necessary for heavy, squeezing ground. Chap. 5 describes the Bunker Hill mine's use of square¬set timber in a new configuration that provides an effi¬cient and safe support for stoping using small load¬haul-dump (LHD) mobile equipment. Chap. 6 describes some considerations in placing the widely used stull in bedded ore deposits. Finally, in Chap. 7, cost calcula¬tions for

Jan 1, 1982

By B Stump

Reliable particle size analysis in minerals processing plants is a critical factor to the economic return of a plant. As recovery of valuable minerals is compromised for particles outside the optimal size range, effective and reliable particle size analysis is more crucial than ever, particularly in the current upswing of the global commodities market. Inefficient particle size analysis can lead to excessive over-grinding, thereby significantly increasing energy consumption and reagent costs, whilst negatively affecting process operation, thickening capacity, water recovery and tailings disposal.Australia’s first installation of a particle size analyser in Iron Ore has been monitored with great interest by the industry. Previously, manual size sampling at Rio Tinto’s Paraburdoo fines processing plant involved off-site sample analysis, with a turnaround measured in days. The Outotec PSI® 500 particle size indicator, commissioned in July 2009, takes approximately three minutes per line at site.The paper will include details on the following:• plant description,• sampling design,• PSI® 500 analyser functionality description, and• key learnings from site.

Jul 11, 2011

By S. Stephen Uslan

The purpose of the study was to demonstrate the effect of positive reinforcement, specifically, social reinforcement (SR), on the frequency of eye, hand, and back injuries at four experimental salt mines. Injury data was collected from January, 1976, for the prePOMOST period and from the onset of training to September, 1978, for the post-POMOST period. All data was collected on a month-by-month basis. For the training period approximately 100 managers and supervisors from five plants were trained in the use of positive reinforcement for occurrences of "safe behavior." Each supervisor was also provided manuals and other supportive materials. Additionally, following training, all supervisors were provided some coaching experience to keep the knowledge and capabilities gained during training from being extinguished. The analysis showed significant injury reductions in two sites and no injury reductions in the other two. When the injury data was corrected for the additional man hours expended in the postPOMOST period, a third site showed reduction in injuries. Similar findings were shown when the experimental sites were compared to other sites in the industry. The results were interpreted to support the hypothesis that the application of social reinforcement is related to a reduction in injuries.

Jan 1, 1978

By AIME AIME

AT the annual .meeting of the Minnesota Section in December, Dr. Leith characterized as a question still open the exact method of origin of Lake Superior iron ores and emphasized it as an important practical problem for the future. He welcomed the step taken last year by Dr. Gruner in presenting a new hypothesis, and asked Lake Superior geologists to meet the challenge of such multiple hypotheses by unbiased, study.

Jan 1, 1932

By H. Askari-Nasab, B. Osei, K. Awuah-Offei

The U.S. coal mining industry consumes approximately 142 billion kWh/a of energy. The U.S. Department of Energy estimates that the industry’s annual energy consumption could be reduced by 49%. This constitutes nearly $3.7 billion of potential savings on coal production costs at 5.3¢/kWh of energy. Additionally, with climate change regulation on the horizon, any benefits from energy savings in the near future are compounded by associated reductions in CO2 emissions. Research indicates that operating conditions significantly affect energy efficiency. Modeling and simulation have been shown to be a cheap and reliable means of evaluating the effects of process interactions and operating conditions. The goal of this work was to apply stochastic process simulation to model the energy efficiency of a typical truck-and-shovel mining system and use the model to evaluate production strategies to improve energy efficiency. The research team conducted energy audits of truck-and-shovel overburden removal and used the results to develop regression models describing truck and shovel fuel consumption. The team then built a stochastic simulation model of the truck-and-shovel overburden removal operation and used it to assess a variety of improvement measures by simulation experimentation. Valid fuel consumption models for shovel loading and truck haulage have been formulated, based on the energy audit results. Valid stochastic process models of truck-and-shovel operations have been formulated to study energy efficiency. The following strategies, in decreasing order of impact, provide the most energy savings for truck-and-shovel overburden removal at the mine: (1) shorten haul roads, (2) increase shovel capacity and (3) increase shovel utilization through optimal truck matching. Additional data will be required to adequately describe operator effects on energy efficiency.

Jan 1, 2011

By William R. Jones, Robert M. Hernon

This report on the Central mining district of New Mexico is the partial culmination of an intensive U.S. Geological Survey effort dating back some 30 years. Robert M. Hernon went to Silver City in 1948 to finish a detailed restudy of the district that had been started in the thirties by Samuel G. Lasky. He was joined by William R. Jones in 1951, and Jones took over as project chief when Hernon resigned to do consulting work in 1953; it was under Jones' guidance that most of the work was brought to completion or nearly so ( 17, 22-24, 26-30). Hernon returned to the Survey in 1958 to work in .the southern Appalachians. Early in 1965 Jones urged that Hernon be reassigned to the Silver City project to help complete the Professional Paper report on the ore deposits of the Santa Rita quadrangle as well as to take over preparation of the report on the Central district for the Graton-Sales volume. This reassignment was approved, and Hernon began work on the present report. By late June he had completed most of it in draft form, and on June 28 Jones and Hernon left Denver for a short trip to Silver City to fill in a few gaps and to reacquaint Hernon with activities in the district, which he had not visited for 12 years. Late in the afternoon of June 29, 1965, as Bob and Bill were 85 miles short of their destination, their jeep collided head-on with a truck that was attempting to pass another vehicle in a cloud of dust. They both died instantly. As the most recent surviving member of the Silver City project (1958-1962), I was given the honorable though rather sorrowful task of putting the Hernon-Jones report "in shape" for publication. Fortunately the manuscript was already in good shape, so that the task has consisted of little more than minor reorganization and editing, and of preparation of the illustrations, abstract, and bibliography. The sections on wall-rock alteration had been left for Jones to complete in the light of his recently intensified interest in alteration geochemistry (25), and it is in these sections only that. the report may fall short, for they have been filled in from a 1958 manuscript by Jones on the ore deposits of the Santa Rita quadrangle that he intended to revise considerably. The shortcomings, however, are largely in the interpretation, not in the field data. As a brief but accurate summary of what was known about the geology of the Central mining district in 1965, this report stands as a fitting testimonial to the scientific dedication of two exceptional men.

Jan 1, 1968

By John Paul Gries

This Bureau of Mines report reviews the mineral industry of the Black Hills area, including Butte, Custer, Fall River, Lawrence, Meade, and Penning- ton Counties, S. Dak.; and Crook, Niobrara, and Weston Counties, Wyo. It includes discussion of geological occurrence, processing, and potential of 27 commodities that have been produced from the nine-county area. The value of mineral production exceeds $70 million annually. Gold and petroleum account for two-thirds of the total, followed by clays, cement, sand and gravel, and rock. The combined mineral industries annually consume 268 million kilowatts of electrical energy, 933 million Mcf of gas, and 2 million barrels of fuel oil. Water consumption is about 10,000 gallons per minute. About 2,700 persons are employed on a year-round or significant part-time basis.

Jan 1, 1974