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Steady increases in longwall production have required operators to apply greater quantities of ventilating air in an effort to control and dilute respirable dust. Significant increases in shearer speeds necessitate that longwall supports also be advanced at a faster rate. Both of these factors may contribute to overall respirable dust levels on the longwall face because as supports are lowered and advanced, broken material falling from the top of the canopy is entrained directly into the air stream. To address this issue, the Pittsburgh Research Laboratory collected respirable dust samples from four longwall faces to characterize shield-generated dust. This paper investigates the influence of air velocity and shield advance rates on respirable dust levels. Also discussed are engineering controls currently used to reduce shield dust and alternative controls being investigated by the National Institute for Occupational Safety and Health (NIOSH).

Jan 4, 2010

By C. Green, J. Uhrie, C. Filippone, A. Guzman

A central aspect of heap leach management and recovery optimization is solution control. Insofar as each heap is unique in physical and metallurgical properties, it is essential to understand the hydraulic parameters that control the migration of solution on a case-by-case basis. Water Management Consultants, as part of an ongoing research effort for Phelps Dodge Process Technology Center, have adapted techniques of parameter estimation for application to data typically resulting from metallurgical column testing. The parameterization is completed within the context of a variably saturated flow model that allows interpretation of available hydraulic information collected during hydrometallurgical column tests. A novel interpretation approach is introduced to extract the necessary hydrodynamic parameters from typical hydrometallurgical data sets. Results from the application of the approach to standard metallurgical test data will be presented together with a discussion of the application of information gained to the design and operation of a heap.

Jan 1, 2002

By William Gleason

"It is the largest mining exhibition in the world that attracts thousands of attendees from around the world to Las Vegas, NV once every four years. Despite the recent struggles in the mining industry, MINExpo International 2016 promises to be as big as ever. In the following pages, Mining Engineering takes a look what some of the more than 1,800 companies plan to showcase during the three-day exhibition.CaterpillarCaterpillar will support MINExpo 2016 with an exhibit showcasing machines, technology, expertise and practical knowledge that miners can apply to help address their cost, productivity and efficiency challenges in today’s mining environment.Caterpillar will once again occupy the largest space at the event and will showcase both surface and underground machines, but the talk at the booth will focus on how Cat technology and know-how combines to help mining operations address and solve the issues that are most important to them. The main stage in the exhibit will feature presentations describing how mining companies, Cat dealers and Caterpillar work together to improve operations.“The challenge for all in the mining industry now is to optimize operations — to drive costs down while creating sustainable businesses that can weather downturns,” said Caterpillar Resource Industries group president Denise Johnson. “We believe that through our expertise and the knowledge of our dealers —combined with innovative technologies and our growing data analysis capabilities — we can help them not only survive, but thrive in these challenging times.” Johnson was selected by the National Mining Association (NMA) to chair MINExpo 2016. “Chairing this show is a great honor, and it’s a testament to Caterpillar’s partnership with this critical industry,” she said. “We’re proud to be a long-time supporter of the NMA, and we are excited to participate in another MINExpo. It’s an opportunity for us all to learn from each other how to increase productivity, control costs and improve overall operations.”Surface mining displays. The surface mining section of the Caterpillar exhibit will showcase the new MD6420C rotary drill. This is autonomy ready and optionally equipped to leverage the safety and productivity benefits of Cat MineStar Terrain. This high-precision drill management system optimizes utilization and improves drilling and blasting operations by accurately guiding the operator and improving precision of hole placement and drilling depth — and the next step is fully autonomous operation, Command for drilling. The third-generation drill incorporates proven Cat components throughout for superior reliability and durability."

Sep 1, 2016

By David van Cleave, David L. Rome

Whether you buy your minicomputer from a manufacturer or another vendor, the first thing you must do is define your needs. With good planning, the initial cost will be low and your return on investment will be maximized over the long term. Involving all members of your staff who will he using the new computer in the planning phase is also important. Their participation will alleviate any potential concerns they may have about new equipment, and their suggestions will provide valuable input for your specifications. After you define your proposed system, survey available hardware and software. The survey will help you in the next step, preparation of specifications. The specifications, along with a quote request, are then sent to various manufacturers. Consider the Manufacturer When selecting your minicomputer, one important item to consider is the manufacturer. Remember, when you buy a computer, you're also buying the services of a computer company. A firm that makes a commitment to its customers and provides a product that is field tested before releasing it for sale is preferable. Examine the company's maintenance and support packages, since every machine requires preventive maintenance. Does your manufacturer or original equipment manufacturer (OEM) support service sites in your area? Has their service record been commendable? Will they provide training for your personnel and a supply of circuit boards so you can retain a degree of self-service autonomy? Three methods of buying a computer involve the manufacturer, an OEM, and the systems house. Buying direct from the manufacturer means you go straight to the source, using no middleman. This gives you maximum flexibility; you can consider every alternative and many possible combinations of computers, peripherals, and software until you find exactly the right system for you. The OEM buys computers direct from the manufacturer and builds them into his own computerized, special purpose product. He usually sells a complete package, including software and hardware, and often noncompetitive equipment as well (a scientific or engineering instrument, for example), designed for the mining market. Because he offers a packaged product, the OEM can often charge less for the system than if you put the pieces together yourself. In many ways, the OEM also provides a unique system. And while the OEM sells a packaged solution, he also usually has the special market knowledge necessary to modify the system to meet your unique needs, if necessary.

Jan 11, 1981

By Phil Pennington, D. Jack Adams, G. Ward Wilson, Virginia T. McLemore, Luiza Aline F Gutierrez, Rodney Shields, Steven Lockwood, Samuel Tachie-Menson

Microorganisms are directly or indirectly involved in many chemical alterations and in the decomposition of minerals required for their growth. Microbial dissolution of sulfide minerals under acidic conditions can produce over 1,000 times more Acid Rock Drainage (ARD) than chemical action alone. Microbial actions can cause precipitation of minerals, adsorption or release of metals, and formation/destruction of organic-metallic complexes. Soluble minerals can serve as oxidizing substrates, electron donors/acceptors in redox reactions, and can be directly involved in cell metabolism. Microorganisms and microbial oxidation-reduction reactions and their contribution to mineral mobilization and stabilization will be discussed.

Jan 1, 2005

The National Mining Hall of Fame will hold its 13thAnnual Induction Banquet during MINExpo International 2000 in Las Vegas, NV. The gala black-tie (optional) event will honor eight legendary leaders of the mining industry. The event will take place at the Las Vegas Hilton Hotel on Sunday, Oct. 8. The induction ceremonies will salute mining greats elected by the board of governors from a list of nominees submitted by mining industry partners and the public. The members of the Class of 2000 will join 151 other inductees enshrined in the Mining Hall of Fame in Leadville, CO. The evening will begin at 6 pm with a cash bar reception followed by the banquet and program at 7 pm. Keynoting the banquet program will be Harrison (Jack) Schmitt. He was the geologist/astronaut of the Apollo 17 mission to the moon in 1972 (see related story on page 26). And he is the only scientist to “kick rocks on the moon.” Schmitt is also a member of the Mining Hall’s board of governors. Schmitt was also the keynote speaker at the First Annual Induction Banquet in Denver, CO in 1988.

Jan 1, 2000

By Tony Peach

Project Description The Ok Tedi Mine is located approximately 18 km east of the Papua and New Guinea-Indonesia border, on the southernmost extremity of the Star Mountains Range, it is situated almost equidistant from the north and south coastlines. The headwaters of the Fly River system are in the Star Mountains. The open pit mining activities are on Mt Fubilan with a (pre-mining) elevation of 2,095 metres (6,871 Feet) in the Western Province. The mine is in an area characterised by very steep topography and dense tropical rainforest. The pit has been free draining but will cease to be so in the first quarter of 2009. Ok Tedi Mining Limited (OTML) required a drainage tunnel to be driven under the mine, if possible before free drainage was no longer possible. The tunnel was required to be at least 5 m in diameter and 4,200 m (13,776 ft) long, with a possible extension of 1,100 m (3,608 Feet) if the mine decided it was required for additional drainage and underground exploration. The tunnel is being driven up grade at 0.67%, and will be connected to the pit by the raising boring of two 1.1 m (3 Ft. 6 In.) diameter shafts from the tunnel level 250 m (820 Feet) below to the pit. In Tabubil, the adjacent township at an elevation of 640 m (2,100 feet), air temperatures range from a mean at night of 20 (68°F) degrees centigrade to a daytime aver-age of 27 (81°F) degrees. Extremes of 12 and 39 (54°F?102°F) degrees centigrade have been recorded. Rain falls, on average, 339 days each year and totals 8,000 mm (315 inches), and have been known to approach 12,000 mm (472 inches) making the area one of the wettest places on earth. The portal site is at an elevation of 1,200 m or 4,000 ft and the air temperatures are a little cooler and the rainfall a little greater. Access to the mine is by air for personnel and light freight and by ship for heavier goods and materials. The port is at Kiunga on the Fly River 153 km from the portal site. The program for the project was tight, the decision to purchase the required TBM was made in July 2007 and the final decision to go ahead with the construction of the tunnel was made in November 2007.

By E. Carvajal I

Large diesel engines provide the mining industry the substantial power and torque needed to move large amounts of material efficiently. But the stresses generated by such power and torque necessitate complex maintenance programs to ensure the utmost operating capabilities are not compromised. Of all its available sensors, the Exhaust Temperature differential between the right and left banks can provide the most valuable indicator of the overall operating condition and potential degradation of a large diesel engine. BHP Billiton Escondida Mining has implemented real-time remote monitoring, diagnostics, reporting, and tracking of Exhaust Temperature differential using Modular® technology. As a result of the processes and procedures put into place surrounding their MineCare maintenance management system, Escondida has proactively replaced over 300 injectors, resulting in an increase of 4% in Engine availability.

Jan 1, 2011

By P. Anyon

Exposure to the microscopic particles in diesel engine exhaust can lead to serious health problems, including the incidence of cancers, heart disease and increased susceptibility to respiratory ailments such as pneumonia, bronchitis, and asthma. In Australia, mining companies and state government authorities are actively responding to this major occupational health and safety issue. Their initiatives place considerable emphasis on routine monitoring of diesel particle matter (DPM) exhaust emissions, both for engine benchmarking and as a part of routine engine maintenance. Implementation strategies follow two complementary paths: determination of individual engines? emission signatures combined with periodic engine re-certification; and co-operatively agreed industry-government engine maintenance programs, which are subject to audit. Both strategies place heavy reliance on real-time measurement of DPM concentrations in engine exhaust, using ruggedized instrumentation, mainly based on laser light scattering photometry. Adding value to this cooperative approach, industry has also collectively funded a government agency to design and manage a database, into which the results of all-routine DPM testing can be uploaded directly by individual mines. This win-win outcome is a great example of how cooperative action between governments and industry can deliver the goods: in this case, a safer working environment, more efficient energy use and the capacity to benchmark performance with industry peers.

Jan 1, 2009

By Robin J. Batterham

We still need to innovate, but it is getting harder. The real price of metals is declining, return on shareholder value is lower than other industries, and there is a shorter-term focus on staying viable in a capital-intensive industry where timeframes for implementation of new technologies can be long (+I5 years). In this environment, the levels of R&D spent by major minerals companies are remaining steady at around 0.2%-0.5% of revenue. This is not large and to remain viable in the future, we need to be smarter about the way in which we do R&D. The mining industry is a knowledge-based industry. Driving down the cost curve demands innovation, which demands knowledge. To be smarter and more effective in our approach to innovation, a new paradigm is required Generating, capturing and using knowledge has evolved from Mode 1 (discipline based and clear distinction between basic and applied research) to Mode 2 (multidisciplinary, team-based approached with flow between basic and applied activities). Mode 2 is now seen to be much more efficient and to deliver better appropriability (Tegart 2003). To survive, we need to innovate, and the best way to do this is collaboratively. Some examples and pointers for the future will be given in this paper. THE CURRENT SITUATION The Rand report and other recent studies have painted a grim outlook for the mining industry. The real price of metals continues to decline (Figure 1) and profit margins remain thin. This is reflected in shareholder returnwhich are well below other industries (Figure 2)-and current management strategies-which reflect something of a "survival mode." The current focus for most mining companies is on short-term, incremental gains

Jan 1, 2004

By Kwang ‘Min’ Kim, Paul T. Behum

The Old Bevier Aerobic Wetland in Macon County, Missouri, was constructed between 1990 and 1991 by the Missouri Department of Natural Resources’ Land Reclamation Program for the purpose of treating acid mine drainage (AMD). The principal source of the AMD is from an underground mine that operated during the 1920's through 1950's, which was partially exposed during surface mining in the 1960’s. Limestone bedding of an AMD collection system provided alkalinity similar to an anoxic limestone drain (ALD). Because the original aerobic wetland failed when a critical dilution water supply became unavailable, the total acidity of the AMD overwhelmed the limited neutralization ability of the aerobic wetland. The aquatic vegetation deteriorated and treatment became ineffective. The Missouri Land Reclamation Program with the assistance of the Office of Surface Mining, Mid-Continent Regional Coordinating Center rehabilitated the Old Bevier Aerobic Wetland in 2001, incorporating newer technologies to improve the performance. The new system, Old Bevier II treatment facility, consists of a 2-stage vertical flow pond (VFP) with associated oxidation cells and aerobic wetlands. This paper discusses the performance of this passive AMD treatment system, updating an earlier report. The new treatment system has operated with nearly continuous net alkaline discharge and a high iron removal rate. Treatment improves during warm months when emergent vegetation is fully established and biologic activity is greater. Reduction in system efficiency is evident during winter months.

Jan 1, 2005

By E. Fahrenkrog, D. Sbartaro, E. N. Cifuentes

An intelligent supervisor using expert system tools and applied to a crushing plant has been developed with a structure based on a model of a human operator. It consists of a knowledge base containing a qualitative model of the process and a rules base with the heuristic logic used by an operator when supervising a plant. The simulation results obtained show the potential of this type of system to supervise the automatic operation of a plant. There has been very significant development in artificial intelligence over the last two decades. Within this development, two approaches can be distinguished, (Winston, 1984). The "model approach," in which the main objective is to understand and model the be¬havior of living systems. The second approach is the "engineering approach." Here, systems capable of performing tasks usually requiring human intelligence are created. As part of this latter approach, knowledge engineering and its main achievement, expert systems, have been developed. Expert systems arose from the need to incorporate the abilities of a human expert in solving realistic problems in which the conventional approach has great difficulties. The first successful applications of expert systems were in medical diagnosis, geophysics, and fault detection. However, since 1971, when Fu (1971; defined intelligent control as the inter action of artificial intelligence and automatic control, some significant developments in the use of artificial intelligence tools for process control have been achieved (Astrom, 1986; Pinto 1988; Fahrenkrog, 1988; and Porter 1987). The modern control theory has made important advances. And, although successful in some applications, it has failed to cope with the practicalities of many industrial processes. As a result, the automatic operation of a plant has been confined to a small region around a normal operating point and to periods without any great disturbance. One of the main reasons for this is the lack of accurate and structured knowledge of the processes involved. Despite this, operators applying their knowledge, experience, and a little intuition, often obtain good results controlling the plant in such situations. Considering the above, the next obvious step is to include similar reasoning capacities in a computational system. The development of such an expert supervisory system prototype applied to a mineral crushing plant is presented. Problem description The problem is to conceive a control system with the ability to handle quali-

Jan 1, 1989

On Nov 1, 2007 House Resolution 2262 ? The Hardrock Mining and Reclamation Act of 2007 ? was passed by the U.S. House by a vote of 244-166. HR-2262, among other things, would impose a 4-per-cent royalty on existing mines with commercial production and an 8-percent gross royalty on all new claims. Not surprisingly, this possible new law was one of the hottest topics of discussion at the Northwest Mining Association?s conference that this year returned to Spokane, WA for its 113th annual meeting on Dec. 3-7. More than 1,800 delegates attended the conference that was held under the banner theme of ?Mining ?. For today and tomorrow.? Northwest Mining Association executive director Laura Skaer was one of many speakers during the three-day conference to respond to the threat to the industry posed by HR-2262 with a presentation titled ?Potential changes to the 1872 Mining Law.? In the presentation that she first unveiled at the Alaska Miners Association?s convention and trade show on Nov. 8, Skaer laid out a comprehensive list of problems with HR-2262. In addition to the association?s obvious concerns about the proposed royalty, Skaer noted that the bill includes a mine veto provision that would allow the Secretary of the Interior the authority to deny an operations permit to a project if the secretary determines that the operation would cause undue degradation to public lands and resources. Potential massive withdrawals from mineral entry are also included in HR-2262. Among the lands that could be off limits to miners under HR-2262 are wilderness study areas, areas of environmental concern and 23.6 hm2 (58.5 million acres) identified as Roadless Rule. States, political subdivisions and Indian Tribes would also have more authority to withdraw lands, she said. To combat the proposed changes, Skaer made 10 trips to Washington D.C. on behalf of NWMA members in 2007. In her presentation at the annual meeting, she also objected to provisions that include no life-of-mine permits and uncertain permit renewals and new and duplicative environmental standards that she said are vague, ambiguous and inconsistent with current federal and state environmental laws. Debra W. Struhsacker, an environmental permitting and government relations consultant, also spoke on the issue of HR-2262 with a presentation titled ?The House mining law bill ? Rip van Winkle is back ? and he?s meaner than ever.?

Jan 1, 2008

By SH. Shahsavari, H. Akbari, M. Noaparast, M. Oliazadeh

Mejel valley zircon ore in Iran is located in north part of Iran and was sampled to evaluate its concentration. The aim of this project was to define the mineralogy of this zone and separating zircon from other minerals using gravity concentrators and magnetic separators. It is constituted of various valuable minerals, mainly zirconium, niobium-tantalum, titanium, rare earth elements particularly cerium-bearing minerals namely zircon, sphene and rare earth elements oxides. We used statistical method for designing of experiments. Yates method used for analysis of basic experiments results. The grade of zircon in primary sample was 1.1%. Different experiments were designed to optimize all required parameters. The final concentration with 75% zircon was produced and final recovery was 79%. Finally, lab-scale based flow sheet was prepared using experiments results.

Jan 1, 2005

By Janet A. Flinn, David G. Fileccia

Machine guidance and control systems have become more pervasive in the mining industry in recent years but not always from mining-experienced providers. Dozers, motor graders, scrapers, excavators, shovels, draglines, drills and haul trucks are just a few examples of the types of heavy machinery now equipped with global positioning system (GPS)-aided guidance systems. While equipment manufacturers are offering their own software, many only supply solutions for the machines they produce. The proliferation of GPS equipment manufacturers entering the machine guidance and control arena has resulted in a multitude of makes and models of GPS receivers. Some of these companies also produce their own guidance software. But they usually just specialize in a narrow range of heavy machinery. So customers are forced to use multiple systems and face new challenges in implementation, training, reporting and inter-system communication.

Jan 1, 2006

By K. L. Lownie

For research and test data to serve a useful purpose, it is essential that it be derived from some known standard test procedure that allows for comparative analysis as well as independent replication and verification. Fan performance data provided by manufacturers is not absolute, and is influenced by the geometry of the test installation. For these reasons, fan test standards have been prepared in order to establish a clearly defined test procedure that allows for comparison of different fan designs, and also allows for the independent verification of test data. Internationally recognized Standards such as BS848, ISO5801, and AMCA 210 etc. are highly prescriptive, and precisely specify test duct configurations, measurement procedures, measurement planes and instrumentation to be used. Provided the laboratory tests are conducted strictly in accordance with the relevant Standard, the performance data will accurately reflect fan performance within the appropriate tolerances for efficiency, pressure and flow when tested in the defined configuration. Major differences in performance exist between a fan tested in accordance with a Fan Test Standard, and an identical fan installed in a mine ventilation system. The aerodynamic performance of any fan will be influenced by the quality of the fan manufacture, the flow system within which it is operating, the location of measurement planes, and the system stability. The flow distributions present in a standardized Laboratory test are unlikely to be repeated in mine ventilation systems, and this will also disadvantage fan performance. Unless the fan supplier takes all of these influences into account, there will an inevitable reduction in fan aerodynamic performance, and the end user will experience a shortfall in expected flow through the mine. The effect on fan performance can range from minor inconvenience to catastrophic fan failure resulting in major rectification costs and significant loss of mine production.

Jan 1, 2009

By D. Nutakor

Rock joint stiffness is not only a poorly known parameter, but also has no established laboratory measurement procedure. This paper presents methods used to determine the normal and shear stiffnesses of healed joints filled with vapor-altered minerals obtained from the Yucca Mountain site in Nevada. Results show that these joints behave linearly up to 85% of their loading history and are stiff with strengths very close to the strength of the intact rock. Factors that might have contributed to the linear behavior of these joints are discussed and areas requiring further investigation are provided. Joint normal stiffness ranges from 7.16 to 64.77 GPa/mm with an average value of 26.93 GPa/mm, while joint shear stiffness averages 11.41 GPa/mm and ranges from 3.09 to 28.41 GPa/mm. Young?s modulus of the vapor-altered joint infilling was calculated from the stiffness of the healed joint. Young?s modulus of the vapor-altered joint filling material averages 7.89 GPa and ranges from 2.15 to 19.43 GPa. Given the pervasive presence of such altered rock, usually in the form of sub-spheroidal 3-D pockets, this property should be of value in any numerical modeling attempting to describe the mechanical behavior of these tuff formations at the level of detail where inclusions might be a factor.

Jan 1, 2008

By Klaus Stoss, Bernd Braun

The sinking and lining of a large mine shaft with 8.0 m i.d. and 1,133 m total depth is described in detail. The ground freezing method was applied to safely sink the shaft through unstable, waterbearing strata. Following a brief introduction to the geological and hydrological conditions and the owner's shaft requirements, is the general technical concept to sink and line the shaft. Particular emphasis is put on the lining system which has to provide stability and absolute watertightness for the lifetime of the shaft, even though mining takes place in its immediate proximity. Machinery and equipment used to execute the work are mentioned and commented. Furthermore, the excavation and lining of the large filling stations using rock anchors and shotcrete are described. Details on performance rates are given.

Jan 1, 1983

By E. P. Deliac

The aim of this joint work between the French Coal Board and the Paris School of Mines is to be able to practically model the behaviour of a transverse drum cutting rock with picks. First a theoretical approach leads to the concept of cutting curves, giving forces and torque against penetration per drum revolution. Then experimental evidence, from full scale and reduced scale testing, validated and confirmed the theoretical shape of the curves. Finally practical applications are given, to improve the design or use of a shearer (or continuous miner). A micro-computer program is being developed to predict the cutting performances of a machine in certain conditions.

Jan 1, 1985

By E. R. Spencer

National Institute for Occupational Safety and Health (NIOSH) researchers conducted an investigation to quantify sound levels and to determine the amount of sound reduction provided by engineering noise controls installed in a talc processing plant. Baseline sound level and sound intensity measurements were performed at the plant and the measurement locations were recorded for comparison to post-control measurements. Follow-up measurements were then made at the same locations after the initial noise controls were installed. The plant subsequently decided to implement additional noise controls and the researchers returned to conduct measurements for a final analysis of all noise controls. The most significant results showed a sound level reduction in the main mill area from a range of 93-104 dB(A) down to 90-94 dB(A), and a total sound power level reduction of 21 dB(A) for air classifying mill 3.

Jan 1, 2008