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Filtration systems with disposable filter elements (DFEs) are used in the underground coal mining industry to control particulate matter emissions from diesel-powered permissible and nonpermissible coal mining equipment. This study was conducted in underground mine conditions to evaluate three types of high-temperature DFEs used in those filtration systems. The DFEs were evaluated for their effects on the concentrations and size distributions of diesel aerosols and concentrations of nitric oxide (NO) and nitrogen dioxide (NO2). Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. After an initial DFE degreening period, the filtration system with all three DFEs was found to be very effective at reducing total mass concentrations of aerosols in the mine air. The effectiveness of DFEs in filtering aerosol mass was found to be a function of the engine operating conditions. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the DFE elements. The effectiveness of DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. Initial heating of certain DFEs resulted in visible white smoke and substantially elevated aerosol number concentrations. The effects of the DFEs on total nitrogen oxides (NOX) concentrations were found to be minor. The NO2 fraction was found to be generally lower for the DFEs than for the muffler. The engine-out NO2 fraction of the total NOX was found to be substantially higher for low-load modes than for high-load modes.

Jan 1, 2011

By David R. Morrey

During the past 50 years, significant research has been performed in the ecology and physiology of plants that colonize soils containing elevated concentrations of heavy metals. Similar work has also been performed on plants that are able to survive acidic and saline environments. Efforts have focused on the ecological analysis of plant communities that occur over a range of metalliferous mining wastes. Investigations have been performed on the mechanisms that allow selected varieties of plant species to survive in normally phytotoxic environments and on the potential applications of metal-tolerant varieties of plant species. The purpose is the remediation and reclamation of mining wastes and soils that contain unusually high concentrations of so-called heavy metals. Characteristics of some mineral wastes Metalliferous mining wastes present special environmental restoration problems because of their toxicity. Potential toxicities are mostly caused by residual metals derived from weathering of low-grade ore or the waste products of mineral processing. In cases where pyrite forms a part of the mining waste, acid generation by oxidation may exacerbate the toxicity problem by promoting heavy-metal mobilization in aqueous solution.

Jan 1, 1995

By Shemek Oginski

The 5 km (16,194 lf) of 6.1m (20 ft) diameter TBM driven tunnel built by the J.F.Shea Co. will serve as sewage overflow storage. The TBM tunnel and four connecting tunnels excavated by drill and blast methods in hard granite will remain unlined. Based on the Geotechnical Baseline Report (GBR), the Contract documents provided a design with no required pattern of rock bolts, no probing, no pre-excavation or consolidation grouting, and lastly, no final lining of the tunnels was deemed necessary. This paper will provide a general overview of these topics with the emphasis on the actual ground conditions encountered versus the projected conditions provided in the GBR and how the GBR reflected the design of the project. Proposed modifications to the temporary and permanent ground support will be presented and the necessity of probing and pre-excavation grouting will be evaluated.

Jan 1, 2005

By M. H. Pelkki, R. J. Sweigard, P. W. Conrad, J. M. Ringe, D. H. Graves

Research has shown that excessive soil compaction is detrimental to the establishment of trees in reclaimed soils. Dry bulk density and penetration resistance are two soil parameters that can be used to indicate the level of compaction in reclaimed soils. It is believed that reclamation practices which minimize soil compaction will produce better results when forestland is the intended post-mining use. The University of Kentucky has developed reforestation test cells on reclaimed soils at a surface mine in eastern Kentucky to test this hypothesis. Each test cell has been planted with various species of trees, and since 1997, data have been collected at these test cells for soil average dry bulk density, average penetration resistance, average depth to refusal, and average survival rate of trees. These data have been correlated to determine the relationship between soil compaction and tree survival rate. It is believed that the two soil compaction parameters may ultimately be used to predict tree survival rates on reclaimed surface mined lands.

Jan 1, 2001

By James A. Madonna

Several universities and colleges in Australia, Canada and the United States, recognized the need to establish or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this, a cooperative study with industry in one state or province from each country was initiated. These include Tasmania in Australia, British Columbia in Canada and Alaska in the United States. The objective of this work was to develop a diversified geoscience educational model at the two-year technical, vocational and continuing education level that provides the source from which any nation can draw the proper educational tools to create a new geoscience program, modernize an existing program or strengthen a weak program. More than 100 mineral industry organizations provided information regarding their specific training needs for support personnel. The data gathered have been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration. These included geological, geochemical, environmental and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model was developed for the three levels of training. The international need for a study of this type was recognized as early as 1980, following numerous contacts from domestic and foreign geoscience educators regarding the structure and success of training within the University of Alaska Fairbanks Mining Extension program, located in Fairbanks. Contacts, correspondence and visits included educators from Australia, Brazil, Canada, Mozambique and the conterminous United States. The need was magnified between 1985 and 1989 at the University of Alaska Fairbanks, when an attempt failed at initiating and developing a two-year geoscience vocational-technology program leading to an Associate of Science degree.

Jan 1, 1994

By M. Hancer, J. D. Miller

It is known from soluble salt flotation practice that the K, Mg double salts of kainite (KClMgSO43H2O), and carnallite (KClMgCl26H2O) are difficult to float and must be converted to other salts such as schoenite (K2SO4MgSO46H2O) and sylvite (KCl) in order to recover potash values. The flotation characteristics of these double salts have now been confirmed in some detail by carefully controlled laboratory experiments with both cationic and anionic collectors. The experimental results are discussed in view of recent experimental findings regarding the flotation characteristics of simple salts, in which the flotation response was shown to be determined by the interfacial water structure and whether the salt could be considered to be a water structure maker or a water structure breaker. The same approach can be use to explain the flotation response of the potassium double salts ; schoenite, kainite, and carnallite. In addition, the sign of the surface charge of schoenite (K2SO4MgSO46H2O), was determined as a function of pH from nonequilibrium electrophoretic mobility measurements. Schoenite appears to exhibit three charge reversals (CR) which can be explained based on surface hydrolysis reactions. The flotation behavior of schoenite is further considered based on solution chemistry calculations, electrophoretic mobility measurements, and microflotation results.

Jan 1, 2001

By G. Bulut

The recovery of copper and cobalt from ancient copper slags from the Küre region of Turkey was investigated. A fayalitic-type of ancient copper slag containing 1.24% Cu, 0.53% Co and 53.16% Fe were subjected to an experimental study. Two different routes were followed to recover the metal values. The first route was roasting the slag with pyrite followed by leaching. The second route was flotation of the slags, roasting of the flotation tailings with pyrite and leaching. The second route was found to be suitable for the treatment of the copper slag studied. In the flotation step, a copper concentrate containing approximately 11% Cu was produced with a 77% recovery while 93% of the cobalt stayed in the tailings. In the roasting experiments, the effects of roasting time, pyrite: slag ratio and roasting temperature on the dissolution efficiencies of Cu and Co were investigated, and the optimum conditions were determined. In the tests, 87% of the cobalt dissolution was observed after one hour of roasting at 500°C with a pyrite: slag ratio of 3:1. The copper dissolution in the tests was 31%. Based on the results of this study, a process flowsheet is proposed for the evaluation of these slags.

Jan 1, 2007

By A. Adu-Acheampong

Stope instability at Ashanti Goldfields Company Ltd. (AGC) is a major concern. Using information from field mapping, major discontinuity sets were defined, Rock Quality Designation (RQD) was determined. The stability of wedges in the stope walls was assessed using the commercially available computer program UNWEDGE(Rock Science, 1992). Analytical results indicate that the presence of graphite infilling in joints contributes to instability, while steeply dipping joints control wedge slabbing and wedge toppling in the hanging wall. Stable stope widths and dimensions were determined to range from8.1 to 30 meters (m).

Jan 1, 2003

Minerals contribute to the U.S. gross domestic prod-uct (GDP) at several levels?mining, processing and manufacturing finished products. In 2008, the estimated growth rate for the real GDP of the United States was 1.1 percent and the nominal GDP was about $14.3 trillion (Table 1). Trends in various sectors of the domestic economy are often reflected in mineral production and consumption rates. For instance, continued declines in the U.S. housing market during 2008 were reflected in further reductions in the production and consumption of cement, clays, construction sand and gravel and crushed stone (mineral commodities that are used almost exclusively in construction), and those associated with the related manufacture of goods, such as ceramic tile, heating and air conditioning equipment, paint, plumbing and sanitaryware, roofing, wiring and wallboard ? all used by the housing industry. The widespread effects of the slowing domestic economy became more apparent in the last three to six months of 2008 when prices for many mineral commodities declined sharply after reaching record highs earlier in the year, indicating significantly lower demand for those materials or products containing them.

Jan 1, 2009

By Patrick J. Doig

In mid-1991, the design/build contractor set to work on the Pergau HEP in a remote corner of Malaysia, armed with only a slim volume of conceptual drawings. The next five years saw roads, power lines, buildings, dams, and over 30 kilometers of tunnel constructed, followed by two years of E&M installation and commissioning. Along the way, the project overcame geothermal groundwater, faults, land disputes, monsoon rains, marauding tigers, and those most fearsome of foes, politicians and the press. This paper is a testament to the ingenuity, commitment, and persistence of the construction industry professionals who brought this massive project to fruition.

Jan 1, 2001

By R. J. Pruett

The Georgia kaolin district is the world’s largest producer of kaolin. Georgia production tripled from 2.87 Mt (3.17 million st) in 1968 to8.35 Mt (9.2 million st) in 1998. Development of the Georgia kaolin industry can be traced to the identification of the mineral resource, the adoption of innovative process technologies and the creation of markets for kaolin. Georgia kaolin is an abundant and high-quality resource that shows a range of advantageous properties. Technical developments in wet processing, delamination and calcination allowed production of high-value products. The use of kaolin pigments in the paper industry provided a market that absorbed the rapid growth in kaolin production.

Jan 1, 2000

By P. C. Holloway

La Oroya zinc ferrite (19.5% Zn, 26.6% Fe, 0.052% Ga, 0.075% In) was roasted with coal under conditions more oxidizing than normally used in a Waelz kiln, and the roasted residues were leached with 200 g/L H2SO4. Overall zinc recoveries of up to 97% were achieved, with 35% of the zinc reporting to the fume after roasting at 1,100°C with a bituminous coal addition of 20%. Under these conditions, 93.2% of the Cd, 13.4% of the Cu, 33% of the Ga, 61% of the In and 18.2% of the Pb were recovered either in the fume or in the leach solution. At 2006 metal prices, the value of the recovered metals is comparable to that obtained from commercial Waelz kiln processing of this residue. Zinc in the franklinite (ZnFe2O4) mineral is reduced to zinc vapor, and, after oxidation, some of the zinc is found as ZnO or as Zn2SiO4 in the roasted residue. Iron reacts to form either hematite (Fe2O3) or magnetite (Fe3O4), with no metallic iron detected in the roasted residue, and less than 2% of the iron is solubilized during leaching. The residue produced after roasting and leaching is, therefore, much more stable than the residue from Waelz kiln processing and should be suitable for disposal in a landfill.

Jan 1, 2008

By C. Keefe, O&apos

Measurements of the quantity of entrained air within processes have challenged instrumentation developers for years. This is particularly true in the unique and demanding operating environment and applications seen in minerals processing. In minerals processing applications, entrained air plays a role in errors seen within nuclear density gauge measurements and in pumping efficiency. It is also the major component of flotation processes. The measurement of the quantity of entrained air, known as the gas void fraction, can now be performed from the outside of a process pipe through CiDRA?s patented passive sonar array-based technology. Within column cells, the need for a robust, no maintenance, accurate means of measuring the entrained air, known as gas holdup, has resulted in a submersible version of this technology. CiDRA?s meter technology calculates the gas void fraction by first measuring the speed at which naturally occurring sound in the process slurry propagates past an axial array of sensors. These sensors are incorporated in a band that is wrapped around the outside of the pipe, resulting in no process downtimes for installation and unprecedented reliability. A known relationship between this speed of sound and the entrained air captured in the form of bubbles within the slurry is then applied in CiDRA?s meter to calculate the gas void fraction. This paper will present the measurement technology, its operation, its calibration and its application in a variety of gas void fraction and gas holdup measurement situations such as pumping efficiencies, hydrocyclone operation, external sparging, and column cells.

Jan 1, 2008

By K. A. Lewandowski

The efficiency of heap leaching is reduced by poor solution flow characteristics (i.e., channeling and ponding) that result from fines migration. Agglomeration of the ore can immobilize fines, but for agglomeration to be successful in copper leaching, an acid-resistant binder is needed to stabilize the agglomerates. Until now, there has not been a satisfactory method to evaluate whether a binder was effective, other than squeezing a handful to see if it ?feels right.? This paper reports on several procedures that have been developed to quantitatively determine whether a binder gives good performance in an acidic solution. These procedures have been used to identify binders that would be suitable for copper heap leaching.

Jan 1, 2008

By D. Symonds, A. J. Richins, M. G. Nelson

Mining activities at Kennecott and Park City are similar in that both districts began operation in the last half of the 18th century, and both operated on a large scale for many years. However, they are different for two important reasons. First, the mines in the Park City district were always underground. The city of Park City was above many of those mine workings. It remained in place after mining activity stopped, and as the town became an up-scale ski resort, property values increased and the tailings dumps became desirable building sites. In contrast, Kennecott eventually became an open pit mine, and the growing pit effectively consumed many of the small towns that had grown up around the underground workings. Even towns on the periphery of the open pit were razed to allow for the disposal of mine overburden. Second, almost all mining activity stopped in Park City in the early 1970s, just as the first rigorous environmental legislation in the United States was enacted. (The Ontario mine operated sporadically until 1982.) Many mine structures, waste dumps, tailings ponds and piles, and tunnels were simply abandoned as the mining companies ceased business or were bought out. Kennecott, on the other hand, has been in continuous operation for more than 120 years, so a closure plan hasn’t been finalized. Nonetheless, environmental and social problems have arisen, and the company has had to address them.

Mar 2, 2022

By Brian Heer, David Young, Randall Essex

The Manapouri Power Station is New Zealand’s largest hydroelectric facility located on the South Island of New Zealand. Constructed in the 1960’s, it includes a 700 MW under-ground power station and a 9.8 km (6.1 mile), 9.2 m (30 ft) diameter tailrace tunnel. The output of the power station is currently limited due to excessive head losses in the tailrace tunnel. To remedy this situation, the Electricity Corporation of New Zealand (ECNZ) retained Woodward-Clyde to design a second tailrace tunnel and appurtenant facilities and prepare Contract Documents for construction. The Project will involve the construction of a 9.8 km(6.1 miles), 10 m (33 ft) diameter, TBM-mined tunnel, hydraulic control structures at the upstream and downstream ends of the tunnel, an underground dewatering shaft and station, and tailrace channel improvements. This paper summarizes the key design and construction issues addressed during the planning and design phases, outlines the risk management provisions incorporated in the Contract, and overviews the Interactive Tender Process (ITP)that was implemented during the pre-tendering and tendering periods.

Jan 1, 1997

By Maurice Grieves

GC. Waterman Mr. Grieves' paper on "Shaft Sinking Today--A Boring Business Tomorrow" in the Dec. 1981 issue of MINING ENGINEERING is an excellent description of recent improvements in speed and costs of shaft sinking. However, shaft boring techniques are not a recent development. In 1935-36, the Idaho Maryland Co. (gold), Grass Valley, CA, bored the vertical 1.5-m-diam Idaho No. 2 ventilation and supply shaft to a depth of 346 m. The equipment was designed and perfected by Branner Newsome and was, I believe, described in "Transactions." Pickands Mather later bored a 1.8-m-diam shaft to a depth of about 305 m using Newsome's design. The Idaho No. 2 shaft cut through hard gabbro, diabase dikes, soft serpentine, very incompetent ankeritized serpentine and a strong fault zone. The completed shaft did not require timber support; the fault zone was cemented. Equipment consisted of a rotating 1.5-m or 3-m core barrel with a slotted bottom which cut a 76-mm kerf. The cutting agent was chilled steel shot introduced into the slot as needed. The driving mechanism and core barrel were lowered into the shaft, the former secured to the wall and the inshaft "engineer" operated the motors which controlled core barrel rpm and advance. After an advance of 1.5-3 m the equipment was lifted out of the shaft, a half(?) stick of powder cut off the drilled core, and it was hoisted to the surface with a cable attached to an eye bolt at the tope of the core. A "shift" consisted of three men: hoistman, equipment operator (down the shaft), and a surface laborer. Advance was variable as equipment and techniques were perfected. Near the end of the job advance was, as I remember, 1.5-3 m per shift. Costs were, as I recall, about $115/m. Up to 4 m cores were lifted out in one piece and swung to the dump by a stiff leg derrick. The Newsome equipment was relatively inexpensive to build and operate and his method should be (more than?) competetive with the methods described by Grieves. W.E. Hawes The author, in mentioning the South African developments of the cactus grab, ignores the parallel development of the Cryderman mucker in this hemisphere. Perhaps a slightly longer history of blind hold drilling would have been in order. Blind shaft boring got a major boost at the Nevada Test Site, as part of the nuclear weapons development, when it was essential to be able to quickly assess depth for weapons testing. One of the early civilian attempts to utilize this technology occurred when Kerr McGee drilled the shaft at the Section 19 Mine at Ambrosia Lake, NM. This twin masted drill rig belonged to a subsidiary of Kerr McGee, not Shaft Drillers. This was a difficult hole, due to bentonitic shales that decomposed. Later advances in drilling fluids eliminated this problem. The Conoco project referred to is not entirely correct, and needs minor amplification: The depth of the development (not pilot) shaft drilled was 684 m, at a diameter of 3.05 m, with a 2.16 m ID hydratatic casing being installed to a depth of 669 m. Conoco Inc., not Challenger, executed the drilling, however Conoco did use Challenger Drilling Company's Rig 14-S. Rig 14-S is unique in that it is specifically designed for shaft drilling, rather than being an oil field rig used for this service. All work was planned and directed by Conoco personnel. Deviation of the aforementioned shaft from vertical was 31 cm. Two smaller shafts (pilot shafts) were drilled with the same rig. These smaller ones were drilled 1.8 m in diameter, to depth of 665 m and cased with .91-m-diam casing, to depth of 650 m to be used as pilot holes for 5.5 m diameter shafts. The total elapsed time for all drilling, casing, cementing, and rig moves was 50 weeks. The constraints mentioned of vertical accuracy, torque, wall collapse, rig set up time, lining time etc., pumping out, etc., may not be as serious as the author implies. First, vertical accuracy: The record achieved by Conoco indicates that with reasonable care, good accuracy can be obtained, primarily by having a fair amount of weight in tension, rather than on the drill bit. Second, the amount of torque that can be applied to the drill stem has been greatly increased by the introduction of larger diameter drill stems, such as the new Hughes rig uses. Third, risk of collapse of shaft walls is minimal with the proper mud program. Basically, the walls are supported by the weight of the mud and it is not removed until some type of casing is installed and grouted in. Here in the real challenge of blind drilling shafts to devise a more economical method of lining bored shafts than using steel casing. The remaining issues were minor at Conoco, provided adequate planning and scheduling takes place. An excellent paper, "Shaft Drilling--Crownpoint Project" by Hassell H. Hunter, presented at the Fifth Uranium Symposium in Albuquerque in Sept. 1981 contains details of this project. A combination of blind boring, with enlargement by either mechanical means (boring machine, or tunneling type shield) or slabbing down, with muck removal through a larger bored shaft would seem to be the future trend in shaft development. The economics, especially for wet conditions, favor this concept over conventional sinking, as has been demonstrated at Kerr McGee --Churchrock, UNC--Churchrock and Conoco at Crownpoint.

Jan 3, 1983

By Antonio De Biase

In October 2006, a 7m Double Shield TBM, boring through very poor volcanic formations, was pushed back by fluid mud, which presence had not been detected during previous field investigations, due to the high covers characterizing the majority of the tunnel axis. The present work describes the investigations made to gain better knowledge of the conditions in front and all around the TBM, the special measures implemented, the exploratory and bypass tunnels excavated, the extraordinary occurrences came true during the execution of these tunnels, the drainage campaigns, the design of the chamber excavated to free the TBM, the dismounting and restarting of the TBM.

By R. J. Boyd

SUMMARY The productivity of drill and blast methods of mining in hard rock is limited by the cyclic nature of the operation, and a plateau of performance has been reached, even with the most advanced equipment developments. Higher mine operating costs and lower metal prices have more than ever generated the need for breaking through these productivity barriers. After initial field testing The Robbins Company has designed and manufactured, on a joint venture basis with Mount Isa Mines, Ltd., Australia, a prototype "Mobile Miner" for continuous cutting of hard rock. This paper describes the cutting concept, the initial application of a completed 1,156 m (3792 ft.) long 14% decline, actual performance and delay analysis, developmental modifications, anticipated performances of a fully developed machine, and possible future applications. Sincere appreciation is expressed to the management of Mount Isa Mines, Ltd., for allowing access to the data used in this paper. The views expressed here are those of the author and not necessarily those of Mount Isa Mines, Ltd. INTRODUCTION A paper titled, "Design and Development of a Mobile Mining Machine", was presented by J.P. Kindsvater at the RETC, New York, in 1985. This paper described the evaluation of a test fixture in an andesite quarry near Seattle, followed by design, construction and

Jan 1, 1987

By R. L. Virta

Editor?s note: Each year, the June issue of Mining Engineering features an industrial minerals review. Several people put in a fair amount of time in developing the material for this issue. Thank you to the industrial minerals annual review editor, to the technical committees chair and vice-chair, and to the authors of the individual commodity profiles. Jim Norman, member SME, of GeoTrans Inc., is the industrial minerals annual review editor. Abani Samal, member SME, of Pincock Allen & Holt, is chair of the industrial minerals technical committees. Technical committee vice chairs include: ? Abani Samal, member SME, of Pincock Allen & Holt, agricultural minerals. ? Aaron McMahon member SME, of Pincock Allen & Holt, ceramics and refractories ? Bradley S. Van Gosen, member SME, of the U.S. Geological Survey, chemical raw materials. ? Mark Zdunczyk, member SME, of Continental Placer Inc., construction materials. ? Jerry Gauntt, member SME, of Marston, fillers and pigments. ? Michael Cheshire, member SME, of Indiana University, sorbents, filters and process aids. ? Candace Trimble, Oil-Dri Corp. of America, specialty minerals. Their help makes possible this June industrial miner-als issue. On behalf of ME readers, the editors thank them. Ball Clay Four companies ? H.C. Spinks Clay (owned by Lhoist Group), Kentucky-Tennessee Clay (owned by Imerys Group), Old Hickory Clay, and Unimin Corp. ? mined ball clay in four states in 2008. Production, on the basis of preliminary data, was 964 kt (1.1 millon st) with an estimated value of $45.3 million. That was a 10- percent decrease in tonnage from 1.07 Mt (1.2 mil-lion st) with a value of $49.2 million that was produced in 2007. Tennessee was the leading producer state with 63 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 73 percent of production was airfloat, 16 percent was crude and 11 percent was water-slurried.

Jan 1, 2009