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By Justus B. Deen

Given that the majority of mine ventilation operating costs are imposed by shafts, the need to predict the resistance of a planned shaft with reasonable accuracy is important. During conceptual design, shaft resistances are usually predicted by use of published friction factors, k, based upon lining and fitting configurations. More often than not, published friction factors do not directly coincide with "real" shafts, so their use is somewhat limited. For more accurate shaft resistance determination, equations both theoretical and empirical may be employed if there is detailed knowledge of the shaft. These equations treat the shaft resistance as discrete components, with their sum being the overall shaft resistance. This paper describes the basic shaft resistance equations and verifies these equations by comparison to field measured shaft resistances. Several shafts were examined which varied in depth, shape and fitting arrangements. Results are presented and conclusions drawn to show that the shaft resistance equations are accurate.

Jan 1, 1991

By J. Partyka, Trevor R. J. Kelly

This paper presents the results on noise testing of a fan only, as well as the results of a steel silencer and of flexible silencers that were connected directly to a fan. On-site facilities and free-field method set by the British Standards Institution were used to measure and then compare the fan only and different practical silencer configuration setups. In order to determine the fan-silencer combination that would give the maximum noise attenuation, total noise intensity, noise contributed to by the fan motor only, as well as aerodynamical noise created through air interacting with the fan parts were considered to obtain decibel readings for the octave bands. Subsequently, the optimal configuration found was the setup with flexible silencers on the fan inlet and the fan outlet. If only one silencer is used, it should be installed on the fan inlet. The aerodynamic noise affects the low frequencies. The flow noise is then overtaken at 1 kHz by the mechanical noise.

Jan 1, 1995

By Walter Küng

The Henderson Coarse Ore Conveying System is a three flight belt conveyor system transporting primary crushed molybdenum ore 24 km (15 miles) underneath the North American Continental Divide. One of the conveyors is 16.8 km (55,200fi) in length with 8,200 kW (11,000 HP) of installed power. The overland conveyor contains 11 vertical curves and 9 horizontal curves, some with radii as small as 1,500 m. he system began full operation in December 1999 and is one of the longest and most complicated belt conveyor systems yet constructed. he design of this conveyor system utilized many innovative engineering concepts including low-energy belt covers, low-resistance idlers, torque-controlled tail drives, combined gravity and active winch take-up systems, small radius horizontal curves and belt turnovers. his paper reviews the start-up of the system, discusses the success of the design and addresses the lessons that can be learned from the first 4 years of operation of this unique conveyor system

Jan 1, 2004

By Warwick Hoffmann, Robin Batterham, David Conochie

CRA has been actively involved in developing a bacterial oxidation process for the treatment of low grade, refractory gold resources. Success in this application is dependant on the design of large, energy efficient reactors. It was identified at an early stage, that the conventional, bottom sparged bioreactor is inherently inefficient because air must be compressed to a pressure above that at the bottom of the tank. This inefficiency increases as the size of the reactor increases. CRA has developed a novel approach to the aeration problem. In this, venturi aeration is used to aspirate air into a liquor stream. The stream is then reintroduced at the top of a draft tube bioreactor. The advantages found with this technique include · low energy requirements and high oxygen utilisations. From results at the 30 m3 scale, we predict an energy usage of -500 kWh/t sulphur oxidised at a scale of 1000 m3.

Jan 1, 1993

By R. Lee Wooten, Marco D. Boscardin, James M. Taylor

An earth pressure balance (EPB) tunnel boring machine (TBM) and pipe jacking were used to construct a 430-meter-long segment of sanitary sewer force main. The force main was constructed by first jacking a 2045-mm-outside-diameter, reinforced concrete cylinder pipe (RCCP) casing through alluvial sands and gravels. Later, a 1220-mm-diameter, ductile iron carrier pipe was installed within the casing pipe. The main concern affecting the construction method selection was the elimination of the need for dewatering, which could cause groundwater flow from deeper, contaminated sands up across a silt aquitard into cleaner, shallower sands. In addition, the method selected reduced the volume of soil to be handled and, consequentially, the potential amount of contaminated soil to be managed. Items discussed in the paper include provisions for handling boulders and controlling ground movements as excavation and jacking occurred approximately 300 mm beneath an active,4800 kPa, 254-mm-diameter natural gas transmission pipeline.

Jan 1, 1997

By M. J. Liesveld, D. Liesveld

For a Colorado mountain quarry, the Water Jet Channeling Method is far superior to Burning, Sawing, Drilling, or Shooting with Primer Cord, Water, or Black Powder. Throughout the life of our quarry, which was founded in 1947, we have used all the methods and turned to the Water Jet Channeler, which we invented and patented as our ideal way to remove dimension granite from our quarry. We jet the block on 4 sides and remove the block with plugs and feathers on the backside. The Water Jet uses approx 7.5 l/m (2 gpm) running at310,000 kPa (45,000 psi) to erode the crystals @ 1sm/h (10sf/h).The 0.533mm (.021”) nozzle oscillates back and forth to achieve an approx 5cm (2”) channel. Using the Jet, we do not lose corners or cause cracks in our red fine grain light class 5 granite.

Jan 1, 2004

By Gerald Pinter, David Nitsche, Márton Bredács, Markus Haager, Andreas Frank

"The reliable prediction of service lifetime of tunnel constructions is of essential technical and economic interest. Polymers used for tunnel liners have to fulfill the requirement of 100 years lifetime. However, today no reliably proven test method is available which confirms such long lifetimes. The current paper introduces a recently started research project which focuses on lifetime prediction of highly flexible, very low density polyethylene (VLDPE) for tunnel geomembranes. Different PE grades in combination with different antioxidant packages are conditioned at elevated temperatures and immersed in different media. Initial results confirmed significant material aging of unstabilized resins already after exposure of up to 34 weeks, at least at the highest exposure temperature of 80 °C. To consider application relevant material properties the material characterization was done by means of tensile tests and dynamic oxidation induction temperature tests. High pressure liquid chromatography was used for further investigation of antioxidant consumption kinetics. 1. INTRODUCTION For a reliable service of modern tunnel constructions a sustainable proofing against water infiltration is essential for the lifetime of the structure. Geomembranes made of polymeric materials have been used successfully for tunnel lining since several decades. Whereas previous geomembranes usually were made of plasticized polyvinylchloride (PVC-P), due to several technical advantages today very low density polyethylene (VLDPE) has become a more and more popular material for such applications. For modern geomembranes, current guidelines expect minimum lifetimes of at least 100 years (ÖBV-Richtlinie 2012). In contrast to this requirement it must be considered that today no test methodology is available which reliably confirms such long lifetimes of polymeric materials."

Jan 1, 2016

By Dave Rogstad

The DART NC-1B Tunnel Project consists of two 5,100 m TBM excavated tunnels, a principal underground station, a partially completed future station, a surface station, and eight associated ventilation shafts and exit tunnels. This paper presents a case history of the project's construction, and will focus on six topics that give this project a unique and unusual history; the TBM excavation, two major differing site conditions, roadheader excavation, polyfiber reinforced shotcrete lining, the NATM design geometry, and a design/build type of contract.

Jan 1, 1995

Lingering effects of the 1990 oil shock that included overbuilding and corporate and individual financial distress caused the Gross Domestic Product to fall slightly to $5.67 billion (US billion = l09). With 254 million people - 697,000 in mining and petroleum - the US has more than 100 million dwelling units and 190 million licensed motor vehicles. New private housing starts fell 15% to one million units. New car production fell 11 % to 5.4 million units. Truck and bus production fell 8% to 3.4 million units. The inflation rate was 3%, while the prime rate of interest was 8.5%. The Producer Price Index (1982 = 100) changed as follows: -fuels and related products and power down 1% to 8l, • metals and metal products down 2% to 120, • chemicals and allied products up 2% to 126, and • non-metallic mineral products up to 2% to 117. Energy Imports of crude and refined petroleum, costing $50 billion, fell 5% to 2.8 billion bbl. Domestic petroleum production rose 1% to 3.6 billion bbl. Petroleum supplied about 39% of US energy, natural gas 24% and coal 22%. The National Energy Strategy was announced in February 1991. Its purpose is to encourage domestic production of fossil fuels and nuclear and renewable energy and to stimulate efficiencies in use. Congress continued to debate the strategy and took no action. Coal production fell 3% to 902 Mt (994 million st). About 60% of that came from surface operations. Seventy-eight percent of the total was used to generate electricity and 3% was coked.

Jan 1, 1992

By E. Lefeuvre

Precambien in age, the phospate deposit under study which outcrops to the south forms a synclinal consisting of only one mineralized horizon. The synclinal strikes SSW/NNE, dips from 30 to 60 NNE and is about 5 km wide. The deposit has been explored by : - trenches and pits about 50 m apart in the outcropping area ; - core drill holes forming lines perpendicular to the outcrop. These lines are about 100 m apart. On each line, the drill holes are about 50 m apart The phosphate layer is clearly visible and has then been defined from the geologicia1 description of drill hole logs. The layer has been divided into two parts : a very rich, altered part at the hanging wall and a poor part displaying opposite physical characteristics, i.e. a fresh and hard rock. With open pit mining in view, the deposit has been divided into a 3-dimension network of blocks, each block measuring 50 X 50 X 100 m. The tonnages of rich and poor ore, PO25, MgO, Si02, CaO and R2O3 grades and the tonnages of barren waste at the hanging wall and the footwall have been calculated for each block. Given the dip of the phosphate layer ranging from 30 to 60° and its relative thickness (between 10 and 15 m), it was impossible or inappropriate to carry out direct calculation by 3-dimension kriging : too many neighboring blocks to obtain sufficient date and impossibility to draw up the morphology of the layer.

Jan 1, 1986

By Donald J. Olson, Thomas J. Lutzenberger, John Ramage

The North Shore Inline Interceptor, Phase IA tunnel is a 8,550-meter (28,000-ft) interceptor tunnel currently being constructed by Traylor Bros./Frontier-Kemper, Joint Venture, using a 9.8-meter (32-ft - 4-in) diameter Robbins tunnel boring machine (TBM). This tunnel is being driven in Silurian age dolomite approximately 91.5 m (300 ft) below ground surface. Significant water inflows were encountered when the tunnel drive penetrated the thinly-bedded Waubakee Formation. Flow increases approaching 0.75 cu m per min per 30 m of tunnel (200 gpm per 100 ft) have occurred in this formation. After driving approximately 2,285 m (7,500 ft) of tunnel (200 m full face in the Waubakee Formation), total flows exceeded 12 cu m per min (3,200 gpm) with about 5.7 cu m per min (1,500 gpm) entering the tun¬nel from the 200 m (600 ft) of exposed Waubakee Formation. Additional water control measures consisting of increased pumping capacity, increased water treatment capacity, surface grouting ahead of the tunnel, grouting ahead of the tunnel face and panning to improve the working environment for installation of tunnel support, were implemented to deal with the large water inflows. Currently (January 24, 1989), 3,400 m (11,000 ft) of tunnel has been driven, total water inflows are in the range of 11.7 cu m per min (3,100 gpm) with only 6.8 cu m per min (1,800 gpm) inflow from about 1,220 m (4,000 ft) of tunnel driven full face through the Waubakee Formation.

Jan 1, 1989

By D. Lelinski, X. Nie, J. D. Miller, J. Hupka, K. Bukka

A preliminary characterization of soil components contaminated at a low level (7 nanocuries per gram) with toxic/radioactive metals has been carried out. Most radioactivity and metals content were present in the minus 100 mesh (<150 µm) size fractions. None of the size fractions examined qualified for uncontrolled disposal at dump sites, thus all material would have to be moved to discharge-controlled landfills. The metal content of the sample was below the limits for economical recovery, therefore eventual processing would be dictated by environmental concerns.

Jan 1, 1992

By Pierre Ollivier, Dominique Morin

A general study of gold refractory arsenopyrite pyrite concentrate bioleaching has been carried out including two continuous bioleach testworks at different sizes, namely one at a laboratory scale with a 100 1 unit at a 2 kg/d dry solid flowrate and the other at a pilot scale at a 100 kg/d dry solid flowrate. Both tests show a 80% bioleaching of arsenopyrite in about four days of treatment and with the same kinetic. Pyrrhotite is attacked at the earlier stage of the bioleaching but pyrite remains unaffected. The weak potential of oxidation associated with the decomposition of arsenopyrite and the abundance of arsenite leads to a high grade of elemental sulfur in the bioresidue which consumes the major part of the cyanide during the gold recovery, furthermore, the arsenite and ferrous produced in solution have to he oxidized to obtain a stable precipitate in the waste products and as outlined in previous works of other authors on this subject the addition of iron to obtain a Fe/As molar ratio at least above 3 is necessary. The agitation equipment used in the pilot unit allowed an optimisation study calculation for scaling-up the design and power requirements of an industrial installation, For the pretreatment of a gold refractory As high-graded concentrate the reagent cost has the greatest part in the operating cost of the biooxidation step due to the necessary retreatment of the biosolution, In that conditions the power cost is quite marginal, actually it is significant for the treatment of pure pyrite.

Jan 1, 1990

On June 4, Kennecott Utah Copper (KUC)marked the centennial of the founding of the original company. Bill Champion is president and chief executive officer of KUC. He said, “What has happened during the past 100 years far surpassed even the most optimistic visions of men like Daniel C. Jackling and Robert Gemmell when they promoted the concept of mass production techniques for a low-grade deposit of copper ore. At that time, it was a totally new way of doing things and the mining leaders of that day scoffed at the idea. They said it would never work,” Champion said. The company will celebrate this once-in-a-lifetime occasion with a few special projects, mainly for the benefit of our employees, said Louie Cononelos, director of government and public affairs for KUC. The company has designed and minted a commemorative copper coin that reflects early steam shovel and locomotive operations on one side, and today’s modern electric shovels and huge haulage trucks on the other side. “The history of the company stems from the ores of the Bingham Canyon Mine. That coin has been encased as part of a10-panel brochure that captures the company’s 100 year history,” he said. KUC also developed special centennial banners and comparable framed posters that were displayed throughout its operations and at selected community locations that have enjoyed a long-time partnership and special relationship with the company. Some of the plants also designed their own centennial hardhat decals.

Jan 1, 2003

By V. Rajaram

R.K. Leininger, N.R. Hasenmueller, and D.D. Carr The content of the paper by V. Rajaram does not fulfill the expectations of the title. But Rajaram submitted the article in October 1983, and he could not have foreseen the numerous developments that would occur before his paper was published more than two years later. Nevertheless, Rajaram failed to mention the interest in oil shale development in southern Indiana beginning in late 1979 and continuing through the present as a result of special financial encouragement of three oil shale projects in May and August 1984 by the Indiana Energy Development Board and the Indiana Corp. for Science and Technology. A session at the 1985 Eastern Oil Shale Symposium in Lexington, KY, Nov. 18-20, 1985, gave the current status of oil shale developments in the eastern United States. Speakers at this session reported on the three Indiana projects. First, Gary D. Aho, Cliffs Engineering Inc., spoke on a feasibility study by Cliffs Engineering and Allis Chalmers for a site-specific pilot plant using the Allis Chalmers process. The plant site is in Clark County, IN, on property of the Midwest Energy Resources Co. The project is funded by $240,908 each from the Indiana Energy Development Board/Corp. for Science and Technology (EDB/CST) and the US Department of Energy (DOE) and $120,454 from the corporate sponsors (total $602,270). Completion is scheduled for mid-1986. Next, Edwin M. Piper, Stone and Webster Engineering Corp., discussed the American Syn-Crude/Indiana Oil Shale Project. This effort followed the completion of two smaller projects funded by the Indiana EDB/ CST: "Testing of Indiana Oil Shale in a Petrosix Pilot Plant" (total funding by EDB/CST at $50,000) and "Assessment of the Petrosix Process for an Indiana Shale Oil Plant" (total funding by EDB/CST at $100,000). The status at the time of the report at the Oil Shale Symposium was that a request for an extension of time for securing nonfederal support had been submitted to the US Synfuels Corp. The proposal included building an 11-m (36-ft) diam retort in southeastern Indiana to process the New Albany Shale and to produce 366 m3 (2300 bbl) of shale oil per day by the PETROSIX process. The Indiana EDB/CST had contracted with Stone and Webster at $401,100 from EDB/CST and $245,835 from Stone and Webster for activities to advance the project in the negotiations with Synfuels Corp. At the time of the report, this project was the only eastern oil shale proposal that was still on the agenda of the Synfuels Corp. As a result of Congressional action in late December 1985, federal support from the Synfuels Corp. is no longer possible. Finally, Victor H. Carr, Eastern Shale Research Corp., described his firm&apos;s project, which is jointly supported by DOE ($227,749) and the Indiana EDB/ CST ($73,850) and is entitled "Feasibility Study to Determine Suitability of an In-Situ Process to Recover Hydrocarbons from Eastern Shale." An area in Scott County, IN, had been chosen, but not a specific 9 x 15-m (30 x 50-ft) site. One burn of a small in situ retort is contemplated as part of the project. Besides these three projects, several reports on shale research were presented. Joseph Damukaitis, American Syn-Crude Corp., reported that a pilot plant using the hydrogenation-extraction (H-E) process (described at the 1984 Eastern Oil Shale Symposium) was 94% built and would go through shakedown with oil shale but would then shift mechanical devices to process coal mine waste. Current status of research on the HYTORT process was then presented by Raymond C. Rex, Jr. Oil shale beneficiation research at the University of Alabama/Minerals Research Institute was reported by R. Bruce Tippin. Scott D. Carter discussed continued research on fluidized-bed retort¬ing of shale at the Kentucky Center for Energy Research Laboratory. Carl E. Roosmagi of DOE, Morgantown, reported on the oil shale research at the Morgantown Energy Technology Center (METC) laboratory. Henry J. Gomberg, Ann Arbor Nuclear Inc., discussed "Radiation Combined with Donor Solvents for Extraction and Up-Grading of Kerogen." Aurora M. Rubel and coauthor Eileen Davis presented results of research at the Kentucky Center for Energy Research Laboratory under the title "The Effect of Shale Particle Size on the Products from the Bench Scale Fixed Bed Steam Pyrolysis of Kentucky Sunbury Shale." Lastly, Maria Rockwell, Technical University of Nova Scotia, presented "Processing and Up-Grading of Low Grade Nova Scotia Oil Shale for Potential Use." A review of shale oil prospects by Gerald Parkinson in Chemical Engineering for Feb. 3, 1986, covers both western and eastern projects and includes a report that the US DOE is funding a few relatively small projects; most of the fiscal 1986 budget of $12 million for shale oil is for fundamental research. Projects include a $3.2 million three-year contract with Hycrude Corp. (Chicago) for development of the HYTORT process and a $1.2 million three-year contract with the University of Alabama&apos;s Mineral Resources Institute on beneficiation of eastern oil shale by froth flotation. The report incorrectly states that current projects include a total investment of $466 million in a pair of 18-month technical and economic feasibility studies for proposed projects in southern Indiana. The correct figure is $468,657 [$240,908 for the Cliffs Engineering/

Jan 10, 1986

By Robert Charles Alfred

Evolution is continuing in the field of rock drilling, Campbell Limestone Company is experimenting in the higher air pressure phase of drilling, It has been determined that there is a definite relationship between Air Pressure, Penetration Rate, Bit & Tool Wear and Life, In our drilling we have determined that &e higher air pressure gives a better penetration rate with less bit wear per foot. Drilling with 180 to 200 PSI air pressure, instead of 100 PSI for air and/or churn drills, has decreased our primary costs by approximately one half.

Jan 1, 1963

By R-H Yoon

The MicrocelTM column flotation technology has been developed based on the fundamental understanding that the first-order flotation rate constant increases approximately as the inverse cube of bubble size. In this technology, bubbles in the range of 100-400 pm are generated by pumping aerated slurry through an in-line static mixer. The high-shear agitation provided by the in-line mixer produces small air bubbles without requiring large frother additions. This column has been tested successfully for processing a variety of non-metallic minerals including kaolin clay, graphite, phosphate, and feldspar.

Jan 1, 1993

By David M. Rubio

The Ortiz Mine is an open pit-heap leach gold operation in central New Mexico processing about 3,100 tonnes (3,400 short tons) per day. It is the initial mining property in the United States developed by Gold Fields Mining Corporation, a subsidiary of Consolidated Gold Fields, PLC. This paper discusses the evolution of the present mining and ore control procedures as adaptions to the characteristics of both the rock being mined and the orebody, and with respect to the fact that mining is done by a contractor.

Jan 1, 1984

By M. Ge

An in-seam seismic (ISS) - based void detection technique was developed and tested for three general mine conditions: anthracite, bituminous and trona. The detection range tested varied from 80 to 100 m for trona mines and from 33 to 66 m for bituminous mines. High quality and broad band signals were obtained from these tests and were used to delineate the voids. The paper provides a brief discussion on the technical features of this void detection technique, the testing conditions and results, and a general assessment of the technique.

Jan 1, 2010

By J. J. Scott

As a Rock Mechanics investigator, the author has, Over his career, attempted to use his best knowledge in developing better rock control fixtures. Based on the experience of nine years of development of friction rock stabilizers, in 1980 he decided to launch a new investigation to develop a unique roof support fixture which would fit the coal mining market. The largest single user of roof bolts in the world is the American coal mining industry, historically using up to 100 million fixtures per year. In 1989 they used approximately 82 million fixtures.

Jan 1, 1990