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By T. Pool

Introduction After two decades of contraction and consolidation, the uranium industry has seen a recent major expansion. Rapidly increasing uranium prices and the ability to raise speculative capital in share markets worldwide have brought over 300 new participant companies into the uranium industry: “juniors” as they are known. These companies participated in a global land rush for known deposits as well as for prospective land positions in order to secure a “piece of the action” for their respective portfolios. Mostly publicly-traded companies, these “juniors” have captured the attention of world’s investing public with spectacular gains; as much as 1,000s of percent in less than four years. The initial phase is over, however, and these companies must now prove that they can be successful in exploration or production.

Jan 1, 2007

By Poltak Sinaga

PT Kaltim Prima Coal?s 13-km (8-mile) overland conveyor (OLC) was commissioned in 1991. It is a conventional three-roller, 35 degree trough belt type. Cost and performance optimization during initial design resulted in a 5.4-m/sec (17.7-ft/sec) belt speed, 1,000 mm- (40 in.-) belt width to convey 1.35 kt/h (1,490 stph) and 7 Mt/a (7.7 million stpy) of coal. Despite a high initial figure, the belt speed was lifted to 6.5 m/sec (21 ft/sec) in 1996 to accommodate mine throughput in-crease. In 2002, a new low loss ST2100 1,100 mm- (43 in.-) wide belt replaced the ST2250 that was due to be changed-out. An upgrade project was initiated at the end of 2003 to further increase the belt speed to increase the OLC capacity to 30 Mt/a (33 million stpy). Upgrading the OLC by increasing the belt speed was the lowest capital option. Increasing belt width and/or modifying the trough angle to have larger cross sectional area was not an economical option because it would require expensive changes and significant down time of the OLC. To achieve 30 Mt/a (33 million stpy), the belt speed had to be increased to 8.5 m/sec (28 ft/sec). Although such high belt speed looked feasible, there was no information at that time of other OLC operating at such high speed. There was a risk that the conveyor would not operate safely and reliably at higher speeds. This risk was escalated by the fact there was no facility to lower or fine-tune the belt speed once the higher belt speed was implemented.

Jan 1, 2009

By A. Vien

Over the past several years, Svedala has developed a continuous charge monitor (CCM) for tumbling mills. It consists of a strain gauge embedded into a rubber lifter and associated electronics. This paper describes the results of a research program to evaluate the technical and economical merits of such a device on a SAG mill. The evaluation includes validation through discrete element modelling and comparison to measured static volumetric load. Inclusion of the measurement into a control strategy and its potential for condition monitoring is discussed.

Jan 1, 2001

By G. E. Jones, G. K. Hoffman

Through the USGS National Coal Availability pro-gram, two San Juan Basin studies have been completed. The study areas are in the northwest Bisti field, Fruitland Formation and in the eastern Standing Rock field, Menefee Formation. Original resources are 4.66 Gt and 3.46 Gt (5.14 billion stand 3.82 billion st), respectively, in the Bisti and Standing Rock areas. Bisti coal resources are greatly reduced by the Bisti-De-Na-Zin wilderness area (1.13 Gt (1.25 billion st)). Technological restrictions remove 31% from Standing Rock original resource. Available resources are 60% (2.79 Gt(3.07 billion st)) of the Bisti original resource and66% (2.26 Gt (2.49 billion st)) of the original Standing Rock resource.

Jan 1, 2000

Man’s search beneath the earth for minerals has always required light, and the devices used to provide illumination have been both innovative and unusual —from stone vessels holding fat and a wick of grass or fiber to a shower of sparks produced by a thin steel disc. While the date when lamps were first used in mines is unknown, Greek and Roman records from 3000 BC definitely mention their use in underground mines. Early Remans most likely used a lamp similar to the one depicted at right. Over the ages, various types of devicives and methods of illumination have been tried and used. One interesting scheme for underground light was to reflect sunlight down the shaft and along drifts using mirrors or other reflective materials. Bunches of resinous wood were also used for underground lighting in many parts of England. In the mid-18th century, the speding mill was developed in England. It worked by rapidly turning a thin steel disc against a flint, causing a shower of sparks to appear. The light produced was uncertain, highly variable, and unsafe in gaseous environments. In Europe, an open pan-type hanging oil lamp was developed and used in some operations in the 1700s. This type of lamp had one opening for a wick and a second opening for refilling the oil reservoir. The lamps were embellished with goad luck charms – a good luck rooster was used in many parts of Europe while a frog and “gluck-auf” were used in Germany. These lamps were introduced in Mexican mines, and a few have found their way into the southwest US. By 1850, a small wick lamp known as the lard-oil lamp, which resembled a tea pot, was invented in Scotland. These lamps were fueled with grease from a packing house –lard, bacon grease, or tallow. Whale oil was also used. Many improvements were made on these lamps, such as the use of windshields and the attachment of miners’ candle-holdm to support the lamp. While these lamps were handy and inexpensive to operate, they were dangerous because their large flame could ignite support timbers or other flammable materials. Miners from the United Kingdom brought this type of lamp into the US. Domestic producers of oil wick lamps were primarily located in Hazleton, PA; What Cheer, IA; Pittsburgh, PA; and Frostburg, IN. The first patent for an oil wick lamp was granted to W. Seybold of McKeesport, PA. Incidentally, these lamps were advertised in a 1903 Sears-Roebuck catalog for 10 cents apiece. Oil wick

Jan 7, 1980

Following a disaster in a mine, it is important to understand the state of the mine damage immediately with limited information. Computational fluid dynamics can be used to simulate and ascertain information about the state of ventilation controls inside a mine. This paper describes a simulation of tracer gas distribution in an experimental mine with the ventilation controls in various states. Tracer gas measurements were taken in the lab experimental apparatus, and used to validate the numerical model. The distribution of the tracer gas, together with the ventilation status, was analyzed to understand how the damage to the ventilation system related to the distribution of tracer gases. This study will be used in future research in real mine measurements to compare collected and simulated profiles and determine whether damage to the ventilation system has been incurred during an emergency situation, the nature of the damage and the general location of the damage.

Jan 1, 2011

By Z. A. Md-Nor

Risk management is an established loss-control methodology that has been applied successfully in many industries. Recently, interest in this structured approach has grown in the mining industry. The main objective of this research was to develop a risk-assessment process, which is a part of risk management, that can be used by the U.S. mining industry to more thoroughly characterize risks associated with haul truck-related fatalities. The assessment is based on historical data obtained from the U.S. Mine Safety and Health Administration (MSHA) investigation reports, which includes 113 fatal incidents that occurred from 1995 through 2006. The risk-assessment process used in this research involves the following basic steps: identification of the risks, risk analysis and risk evaluation. The preliminary hazard assessment (PHA) method is used in identifying and quantifying risks. Risk levels are then developed using a pre-established risk matrix that ranks them according to probability and severity. The resulting assigned risk value can then be used to prioritize control strategies. This paper is a part of a detailed study on risk assessment for equipment-related fatalities in mining sponsored by the Western U.S. Mining Safety and Health Training and Translation Center.

Jan 1, 2008

By L. B. Hales

Expert control of grinding and flotation plants has been successfully used in the minerals industry since the 1970?s. The earliest of these systems were written in a hard-coded fashion in FORTRAN, BASIC or Pascal. Second generation systems were built using the first experimental expert system shells that were being developed in the artificial intelligence community. Later systems were deployed in expert systems designed for real-time processing plants that also include the ability to model the process with neural network models and optimize setpoint selection through the use of genetic algorithms. [1,2] In spite of the fact that significant performance increases have been achieved using these systems they are not perfect and can be improved. They suffer from the static nature of their rules and to a degree the process models. There is an opportunity to further increase system performance by systematically taking advantage of the tremendous amount of data produced by the expert system to improve the design, the heuristic rules, the model topologies and the use of the models. Data mining refers to extracting or mining knowledge from large amounts of data where the objective is to automatically analyze, classify and summarize the data to automatically discover and characterize trends in it and to automatically flag anomalies. [3] Clearly, modern process control systems are capable of collecting vast amounts of data. Without a doubt, these data contain important information on the operation of our plants and their ultimate optimization. Coupling the information mined from these data with Expert Control Systems should produce more effective control and greater knowledge of the grinding process and the flotation process. Now, with the advent of effective monitoring of entire minerals plant electric consumption it is possible to not only optimize plant production in real-time it is possible to analyze total plant electrical consumption and incorporate it into the plant control logic thereby improving the overall plant economic performance. This is particularly important with the ever more complex power contracts that plants operate under.

Jan 1, 2012

By P. Campbell, E. M. Gardy, L. Hachkowski

Introduction The efficient process control of a uranium mill and its associated mining operation requires a nearly continuous knowledge of the uranium concentration in the ore. Generally, the approach is to use laboratory assays of grab samples from the mill feed belt. In some cases, elaborate and expensive systems have been used to ensure random sampling, but even with these systems, mass-balance discrepancies still exist. There is a requirement for an on-line instrument that can give a prompt, accurate analysis of a large portion of the feed stock. The authors have recently evaluated a laboratory system that achieves these goals using neutron activation and delayed neutron counting. The development of the on-line uranium ore analyzer is a consequence of previous work done at the Whiteshell Nuclear Research Establishment (WNRE) (Campbell et al., 1978 and 1981), and is based on the emission of delayed neutrons after the neutron irradiation of fissionable materials. The mechanism of delayed neutron emission has been described (Keepin, 1965), but briefly is as follows. The fission fragments resulting from irradiation are in an excited state. Certain of these delayed fission products, precursors, decay to a more stable state by the emission of a delayed neutron. The delayed neutrons can be divided into six groups with effective half-lives ranging from 0.2-55 sec. It is important to note that more than 50% of the delayed neutrons are emitted within the first 6 sec after irradiation; this has an influence on the design of the analysis instrument. Measurement Cycle The measurement cycle involves a neutron irradiation, a delay time, and a counting period. The laboratory demonstration model of the ore analyzer comprises a californium-252 neutron source, a source chamber, a pneumatic transfer facility, and a neutron irradiation and counting module (Fig. 1). The ore sample is placed in the irradiation chamber. The neutron source is transferred to the center of the chamber for a 5-sec irradiation while the helium-3 thermal neutron detectors are switched off. As the source returns to the storage chamber, the detectors are switched on and the delayed neutrons counted. The total assay cycle is 16 sec. The current instrument design calls for the ore to be cut from the main belt every 16 sec by a mechanical arm and dropped into the analyzer directly, or via another belt. The cycle starts when there is a sufficient mass of ore in the irradiation chamber to depress a switch and stops when the delayed neutron count is finished. The ore is then dropped through the bottom of the analyzer chamber and returned to the main belt. The counts from each cycle are accumulated and the data reduced to give the desired information. Key for Fig. 1 A-Helium-3 neutron detector B-Wax moderator for neutrons C-Irradiation chamber D-Funnel for receiving ore E-Gate F-Transducers G-Biological shield for neutron source H-Transfer tube for neutron source I-Neutron source J- Microprocessor K-Accumulator for hydraulics L-Control panel M-Electro-hydraulic servo valve to control movement of the source N-Electro-hydraulic proportional valve to control movement of the gate O-Hydraulic power unit Irradiation and Counting Equipment Irradiation of the ore is achieved using a 1 X 10 7 neutron*s-1 californium-252 neutron source. The source is contained in an iron capsule and pneumatically transferred between the irradiation/counting and storage chambers. The irradiation/counting chamber possesses 12, 600-mm (24-in.) long helium-3 thermal neutron detectors embedded in an annulus of wax (Fig. 1). Two sets of six detectors are each interfaced to a preamplifier, amplifier and single-channel pulseheight analyzer system, and the two systems are connected to a scaler. A special timing unit controls the transfer of the source and the on and off switching of the detector assembly, in sequence with the movement of the source. Results and Discussion In the experimental demonstration, using the 107 neutron.s-1 source, a 10% uranium ore was measured to ± 10% (2o total error) in 10 cycles and ±6% (2o) in 100 cycles. Since a larger source was not available, it can be statistically predicted that a 109 neutron-s-1 source could be used to measure a 0.1% ore to ± 10% (20) in 10 cycles. The uranium can occur as discrete nonhomogeneous particles in the ore, and the error caused by such a distribution of particles is ± 4% (2o), as determined by

Jan 1, 1984

Newmont?s Twin Creeks Mine, located in northern Nevada, is producing gold ore from surface mining operations. The ore is currently processed at three different on site facilities depending on the ore type and the grade. The processing facilities operate under stringent geochemical blending constraints that must be met from mine ore deliveries and off site sourced ore. To analyze various strategic options, the technical team utilizes the mathematical optimization approach. However, due to the size and the complexity of the operation, there are unique challenges in optimizing life of mine production scheduling. This paper describes those challenges and the methodology developed to take advantage of different scheduling software systems that effectively compensate each other and result in reasonable guidance. The paper also describes how those scheduling results are reflected in detailed mine plan and cost estimate work.

Feb 27, 2013

By W. P. Diamond, S. L. Cario, F. Garcia, J. D. Byars, T. P. Mucho

The National Institute for Occupational Safety and Health (NIOSH) has been conducting research at a Pittsburgh Coalbed longwall mine to evaluate and optimize bleeder ventilation and gob gas venthole longwall methane control systems. Gas flow into these two methane control systems was investigated using a combination of Sulphur Hexafluoride (SF6)tracer gas studies and gob venthole pressure monitoring experiments. The insights gained from this research has facilitated the development of a longwall subsided strata methane control system conceptual model. This model provides the basis for design suggestions to increase the efficiency of the gob gas venthole system to permit the bleeder ventilation system to become a "safety net" for methane control.

Jan 1, 2000

By M. E. Gershon

I would like to congratulate Professor Gershon on an idea that is obviously valuable and is certainly new to me. It has, however, to be further developed, in that one can get fallacious results by limiting oneself to positional weights. In the example problem, the positional weight of one block was 8.6 (the 8.0 value in the paper was incorrect) for 36 units in the cone, for a mean block value of 0.239. The positional weight of the second block was 4.4 for 15 units, for a mean block value of 0.293. Surely one would expect the second block to be rated higher. Additionally, the time value of money adjustment cannot be determined by depth, because the time that a block is mined is determined by the mining sequence, not depth. Figure 1 shows a slightly altered version of Professor Gershon’s pit. The overall value of the pit is the same, as are the total values under each of his blocks. The values in the right-hand cone have been reversed top to bottom, and the values in the rest of the pit adjusted to keep the central cone total unchanged. All values have been multiplied by 10. Figure 2 shows the sequence of mining, at three blocks per year, for Professor Gershon’s pit, and Fig. 3, the sequence for a pit under the other block. Table 1 shows the value and discounted value (157. ) of Professor Gershon’s pit, and Table 2 shows similar values for the second pit. It is apparent that the second pit schedule is more valuable than the first.

Jan 12, 1987

By Z. Yu

Low-rank/oxidized coals respond poorly to oil agglomeration. Emulsification of kerosene in the presence of surfactants dramatically reduces the size of the kerosene droplets. While this dramatically reduces the amount of oil that is required for efficient agglomeration (down to 0.25-0.5%), more importantly, the surfactants entirely change the electrokinetic properties of the oil droplets and thus the interaction between oil droplets and coal particles. Consequently, kerosene cationic emulsions can efficiently agglomerate oxidized coal particles. The agglomerates obtained in such a process can still be recovered by screening. Surfactants can affect fine coal filtration very profoundly when used to emulsify the oil which is utilized to agglomerate coal prior to its filtration. This sequence is much more logical than the use of flocculants - highly hydrophilic polymers - as filtration additives to aid dewatering of flotation concentrates. Although such polymers flocculate coal particles, they also render coal surfaces hydrophilic and make reduction of the cake moisture content difficult.

Jan 1, 2000

By Eric Eisold

The Wachovia Headquarters and Arts and Cultural Campus project in Charlotte, NC includes a 1.5 million square foot, 48-story office tower, two museums, an Afro-American cultural center and a 1,200 seat theater for the performing arts. Public access to the Cultural Campus is through two pedestrian tunnels constructed under city streets connecting to parking garages. The 5.7 m wide by 4.7 m high mined tunnels were procured through a design-build contract. The tunnels were designed as initial/final shotcrete linings with a sprayed water barrier sandwiched between layers of shotcrete. In addition, the mix design was supplemented with a cementitious admixture to develop internal water resistant properties in the shotcrete.

Canadian mining giant Teck Resources Ltd. will be the exclusive supplier of the metals used in the production of the more than 1,000 medals to be awarded at the Vancouver 2010 Olympic and Paralympic Winter Games. Teck, the diversified resource company headquartered in Vancouver, B.C., is providing 2.05 kg (4.5 lbs) of gold, 1,950 kg (4,300 lbs) of silver and 903 kg (2,000 lbs) of copper sourced from its operations around the world. In addition to the raw materials mines, this year?s medals will make Olympic history as they will be the first to contain metals recovered from processing the circuit boards from end-of-life electronics (e-waste) that would have otherwise been destined for a landfill. After mining or production through a variety of smelting and recovery processes, each metal has been refined to enhance the metal purity.

Jan 1, 2010

By E. Topuz, C. Patrick

Longwall face-to-face transfers can cost more than $100 per minute in lost production potential and $100,000 for personnel and supplies. Such high costs make extensive planning and control of the transfer process a critical necessity for the economic feasibility of longwall operations. Operations research techniques are used for the analysis and modeling of longwall face-to-face transfers. Transfer data has been collected from companies who operate, over 35%, of the total US longwall faces. Comprehensive sequence networks of existing longwall transfers were developed; simulation was used to generate models of transfers under Carving conditions; and the economic feasibility of tine-cost tradeoffs in the transfer procedure was investigated.

Jan 1, 1994

By S. Hadley, M. Placha, M. Mishra, V. Choudhry

Under a DOE-funded project, four advanced flotation technologies (the Jameson cell, the Outokumpu HG Tank Cell, an open column and a packed column) were evaluated at the benchscale to identify the technology or combination of technologies that best improved fine coal recovery and reduced processing costs. The results indicated that two-stage application of the Jameson and packed column cells provided the optimal performance. Subsequently, proof-of-concept scale testing was conducted at the Cyprus Emerald Coal Preparation Plant. The results confirmed that levelized production costs were lower using two-stage cleaning with the Jameson cell followed by the packed column.

Jan 1, 1999

By R. L. Virta

Four companies mined ball call in four states in 2009, H.C. Spinks Clay Co. Inc. (owned by Lhoist Group), Kentucky-Tennessee Clay Co. (owned by Imerys Group), Old Hickory Clay Co. and Unimin Corp. Production, on the basis of preliminary data, was 820 kt (904,000 st) with an estimated value of $39.4 million. That was a 15-percent decrease in tonnage from 967 Mt (1.1 mil-lion st) with a value of $44.3 million that was produced in 2008. Tennessee was the top producing state with 59 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 71 percent of production was airfloat, 18 perc

Jun 1, 2010

By H. Polat, Q. Hu, S. Chander

The collection efficiency of dust particles was determined in a laboratory dust chamber equipped with a water spray. Measurements were made in the presence of selected nonionic, cationic and anionic surfactants. For the nonionic and the anionic reagents, efficiency was maximum in a narrow range of concentration. The surfactant concentration corresponding to high collection efficiency was usually much below the commonly used concentration of l%, however. In comparison, much higher collection efficiency was observed for a cationic surfactant at extremely low concentrations. For delineating the mechanism of capture of dust particles, surface tension and contact angle results were used to obtain a correlation between the work of adhesion and the efficiency of collection. Such a correlation was reasonable for the nonionic surfactants but not for charged surfactants. In the latter case, electrostatic interactions between charged droplets and particles were more important, especially for the cationic reagent.

Jan 1, 1992

By Steve Kral

"Liebherr, as most anyone involved with the global mining industry knows, is one of the world’s largest makers of mining and construction heavy equipment. The familyowned company has been around since the 1940s and, according to Stefan Heissler, by the end of next year, will employ about 44,500 people worldwide. Heissler is a member of the board of directors of Liebherr International AG.It all started for the Switzerland-based company when Hans Liebherr first recognized a need for heavy equipment in the construction industry, Heissler said. His first product, introduced in 1949, was the TK10, a mobile crane that, at the time, was a groundbreaking innovation to the heavy construction industry. From there, the company began its growth into a world-leading heavy equipment manufacturer that always relied on innovation.In October, Liebherr gathered a group of mining and construction magazine editors in Leoben, Austria to take a look at the company’s latest addition to the global mining and construction markets. On the mining side, Liebherr provided a demonstration of its T-236 100-t (110-st) haul truck and the PR- 766 50-st (55-st) crawler tractor. The one-day demonstration took place at the Erzberg iron mine near Leoben, where both machines are being proven.The Erzberg Mine, operated by VA Ersberg, has been in operation for about 1,300 years and is said to be Europe’s largest surface mine. It employs about 230 people and mines about 12 Mt/a (13,200 million stpy) of ore, producing about 3 Mt/a (3.3 million stpy) of fine-grained iron ore.T-236 rigid-frame truckThe new T-236 rigid-frame dump truck, with a diesel electric drive system, is Liebherr’s entry into the 100-t (110-st) class and is the first in this class with a four-corner, oilimmersed braking system. The haul truck was first introduced during the 2016 MinExpo in Las Vegas, NV. The unit has since successfully completed its testing phase and is currently in its first field operation trials at the Erzberg iron mine in Austria."

Jan 12, 2017