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On Dec. 20, 2013, an 8-m (26.2-ft) diameter Robbins hybrid single shield/earth pressure balance tunnel boring machine (EPB TBM) was launched to bore the Grosvenor decline tunnel for Australia?s Anglo American coal mine. The machine was built using onsite first time assembly (OFTA) in order to fit within a tight project schedule. Assembly at the remote jobsite near Moranbah, Australia took about four-and-a-half months, and then the machine was walked down into a launch tunnel. Two decline tunnels, at grades of 1:6 and 1:8, will be used for mine access to new coal seams. The hybrid machine is tackling mixed ground conditions ranging from sand and clay to varying types of sedimentary hard rock up to 120 MPa UCS, as well as coal seams. Methane gas is expected to be present throughout the tunnel, so the machine has been designed as explosion-proof-compliant to ERZ-1. ?Grosvenor is the first underground coal mine in Queensland to use a TBM for drift construction,? said Glenn Tonkin, Grosvenor project director. ?We are proud to be pioneering this technology.? Only about 300 m (984 ft) of ground in each decline tunnel is expected to require EPB mode, while the rest of the tunnel will be bored in hard rock mode. Thus, the design was optimized toward hard rock excavation.

By H. Zhao, R. Liao, W. Qin

Theoretically, controlling redox potential to a relatively low value and inhibiting jarosite formation on the chalcopyrite surface would be an effective strategy to accelerate the bioleaching of chalcopyrite. In this work, using limonite as seed crystals, the effects of the goethite precipitation process on the bioleaching of chalcopyrite were studied for the first time. The bioleaching results showed that the addition of limonite controlled the redox potential in an appropriate range and promoted chalcopyrite dissolution through the removal of ferric (Fe3+) ions. X-ray diffraction and scanning electron microscope analyses indicate that limonite significantly induced the goethite precipitation process and inhibited the production of jarosite. We conclude that promoting the goethite precipitation process with limonite is an effective strategy in accelerating the bioleaching process of chalcopyrite.

By Sam Ash

The Murray Mine was one of the first mechanized cut-and-fill underground gold operations in northern Nevada. At the end of 2002, mine production began to decline. So the mine entered a phase of remnant mining and began preparations to close down. The remaining mining took place along the ore waste boundary in previously condemned areas and in challenging ground conditions. To remain economically viable, new techniques were implemented in operations, geology, engineering and rock mechanics. These improvements pushed the edge of known and accepted mining practices and have allowed the Murray Mine to remain in operation.

Jan 1, 2006

By S. Slottee

The technology of making and using ?paste? from mine tailings is increasingly well known by the minerals industry. The primary applications are water recovery and ?stacking? of tailings with minimal use of dams and ponds. This paper highlights some applications, other than water recovery and stacking, that have come to the attention of a paste thickener equipment supplier. As generated by thickeners, paste (also called ?thickened tailings?) is a non-settling, relatively high concentration, suspension of solids that can be pumped. Paste deposits with an angle of repose, allowing minimal use of dams. High solids concentration allows more water recovery at the paste thickener than is achieved in conventional and high rate slurry tailings thickeners. This paper is based on paste as produced in a flow sheet that includes a thickener, underflow pumps that are typically centrifugal, transfer pumps that can be centrifugal or positive displacement, and a distribution system at the deposition site. Examples of paste applications other than water recovery or stacking include: ?mine? an existing tailings pond by removing slurry, recovering coal or iron ore values, and return the new tailings to the pond as a paste that does not res-suspend; use paste to seal an existing tailings pond from leaking to groundwater or to an underground mine; extend the life of an existing tailings pond by thickening the tailings to paste; move an existing dry tailings impoundment to a new location by slurrying, pumping, paste thickening, and redeposit; minimize the size of a filter by paste thickening the feed; operate a paste thickener and filter in parallel on a tailings stream with re-mixing to achieve a high solids concentration. The use of paste tailings technology has been expanding over the last 15 years. The applications, both implemented and under consideration, are increasingly diverse and include all minerals tailings. Tailings handling designers should always consider a paste option to the conventional slurry solution.

Jan 1, 2011

By John Songstead

INTRODUCTION The Bunker Hill mine, located at Kellogg, ID, in the Coeur d'Alene mining district, has been a major pro¬ducer of lead-zinc-silver ore since 1887. Since its dis¬covery, it has produced over 25 401 171 t (28 million st) of ore from 20 to 25 veins and ore zones. The mine now covers an area of approximately 1.609 km (1 mile) in length and 0.8 km (1/2 mile) in width and extends from 1097 m (3600 ft) above sea level to 488 m (1600 ft) below sea level. Production is presently at a rate of 1542 t/d (1700 stpd). During 1965, a new stoping method, the Bunker Hill pillar system, was developed to enable the profitable mining of large, low-grade zinc ore bodies. The system was specifically designed to in¬corporate the Atlas Copco T26GH rubber-tired loaders. High productivities were achieved, and the method was adapted for mining the higher grade stopes where large timber square sets are utilized. This results in nearly 100% extraction. GEOLOGY The area encompassing the Bunker Hill mine lies immediately south of the Osburn fault, a major east-west striking, deep-seated strike slip fault which is the dominant structural feature in the Coeur d'Alene district. The Bunker Hill forms a series of veins and mineralized zones which occur as link structures, tension fractures, and breccia zones in folded, interbedded argillaceous quartzites of the Revett and St. Regis formations of the Precambrian belt series. The Rosco ore body is predominantly a zinc ore body above the Cate fault, which is presently known to occur from the 13 level. [elevation 488 m (1600 ft)] to the 1600 level [elevation 304 m (1000 ft) ]. These ore bodies are stringer zones with at least one dominant 1.8 to 4.5 m (6 to 15 ft) wide band of ore. They dip 0.09 to 0.26 rad (5° to 15°) steeper than the local 0.61 rad (35°) dip of the Cate fault, and also deviate 0.26 to 0.52 rad (15° to 30°) in strike from the Cate. Because of the flat dip and fractured weak hanging wall, normal cut-and-fill mining has not proven practical in this ore body. The mechanized timber methods described in the next section and the Bunker Hill pillar system are the mining methods successfully used. MINING METHODS While pillar stoping and mechanized cut-and-fill stop¬ing methods were obviously superior to the widely used timber stoping methods, as far as cost and productivity

Jan 1, 1982

By Rod L. Norfleet

Cemented tungsten carbides are a sintered powder - metallurgical product essential to modern industry. Because of their moderate unit price and our dependence upon foreign sources for the component raw materials, a growing recycling industry has developed in the United States. There are two basic approaches taken to recycling cemented carbides; those which leave constituting materials unaltered or direct-reuse and those which separate the constitutes back to the raw components. To separate the carbides back to their raw components usually requires expensive chemical processing and is thus confined to the lower value materials such as grinding sludges. The direct-reuse methods recycle cemented carbides back to an intermediate level, a powder capable of being recompacted and resintered into a functional end-product. The three most commonly used methods of direct-reuse recycling, the coldstream process, bloaching and the Bernard or zinc process, are reviewed,

Jan 1, 1984

By J. Kretschmann, A. Müterthies, T. Rudolph, C. Yang, P. Goerke-Mallet

Catastrophic failures of dams and tailing storage facilities (TSF) have triggered the development of integrated ground monitoring concepts for hazard assessment, risk management and public safety. These concepts are based on knowledge and expertise of persons technically responsible for TSF. The aim is to combine this implicit and explicit knowledge with the data of in-situ- and remote sensors. Risk management for TSF must include a comprehensive monitoring program that integrates data from ground based-, air-borneand satellite-based sensors. Researchers at Technical University Georg Agricola (THGA) in Bochum, and EFTAS, Muenster, Germany, are fusing a variety of sensor data to enhance the capability and performance of TSF monitoring to ensure public safety downstream of TSFs. This paper describes the variety of sensors implemented in numerous research projects. It gives an outlook in terms of planned satellite missions with innovative equipment like hyperspectral sensors. The implementation of the data of these sensors in the analysis will increase the understanding of spatio-temporal impacts of mining activities. Future opportunities are explained by a datacube approach.

Mar 2, 2022

By A. Dell’Era, E. Ciro, C. Lupi

The paper explores the recovery of indium via electrowinning from sulfate baths, focusing on the impact of different cathodic supports (AISI 316L and nickel) on process parameters such as electrolyte composition, current density, and temperature. The study compares productivity, morphology, and structure of indium deposits on both cathodes, finding that nickel cathodes generally yield better results.

Nov 1, 2023

By R. H. Weiland

The dewatering of flocculated clay suspensions by compression in a centrifugal field has been investigated. The results are evaluated with regard to both direct applicability to centrifugal dewatering, in solid-bowl centrifuges for example, and indirect applications to gravity sedimentation systems. It is well known that sediment consolidation under gravity depends on structural characteristics such as permeability and on the "self-weight" of overlying sediment layers. An important objective of the study has been to evaluate the self-weight effect using centrifugal forces to simulate consolidation in deep sediments. In this way, small-scale laboratory tests can be used to predict the rates and limits of sediment compression in industrial systems such as thickeners and settling ponds. Experiments have been conducted in which the sediment mass and initial structure were maintained constant while the effective sediment weight was varied by centrifuging at different speeds. The effects of initial structure have also been studied using controlled variations in flocculation conditions.

Jan 1, 1993

By A. Habibi

The ventilation survey was conducted in an underground longwall trona mine. The mine is relatively shallow and categorized as a gassy mine. The ventilation system consists of nine shafts (three intakes and six exhausts). Three surface based axial fans ventilate the mine configured in a blowing arrangement. Following the ventilation survey airflow quantity, frictional pressure losses and air psychrometric characteristics have been quantified. An accurate resistance survey has been conducted to calculate the pressure drop with regard to moving cages and skips in the shafts. This paper discusses the benefits of utilizing high accuracy digital pressure transducers and psychrometers in a ?leapfrogging? survey to gather data needed to build the computer ventilation model. Two underground booster fans with VFD are currently idle but available at the mine. The ventilation model has been used to determine the optimal booster fan locations to decrease the overall operating cost by reducing the load carried by the main fans. A leakage study has been conducted to evaluate the effects on the system of additional pressure from a booster fan. The study finally prepares a future ventilation model for the next fifteen years of mine operation and investigates the effect of proposed scenarios.

Feb 27, 2013

By W. M. Cross

The hydrophobic character of sapphire surfaces in SDS solutions was examined with respect to the aggregative nature of the adsorbed surfactant phase. It was found that, at equilibrium, sapphire surfaces having adsorbed SDS bi-layers exhibited no contact angle. Conversely, when the adsorbed SDS was found to be mi-cellar in nature, sapphire surfaces developed significant hydrophobic character. The surface states as detected by Fr -IRIIRS conformational analysis were found to be reversible with temperature. The variation in adsorption density with temperature was studied by in situ Fr-IRIIRS. The isosteric heat of adsorption was calculated to be -1.6 kcal/mole. Although the adsorbed SDS was found to undergo a reversible phase change between 25 and 32°C, similar to SDS in solution, the extent of adsorption was not reversible with temperature.

Jan 1, 1993

By Oren Tranbarger

The ability to sense or detect the coal/non-coal interface during mining can provide numerous advantages for improving net coal recovery and quality, for increasing productivity, and for mining coal which would otherwise be ignored. This is particularly true when considering multiple, pitching, and thin coal seams. This paper discusses the application of coal interface sensing and examines several potential coal interface sensing techniques with respect to state-of- the-art, design, performance, and cost criteria. Four interface boundaries are considered: the roof, the floor, the rib, and the forward region.

Jan 1, 1982

By J. W. Butwell

Anaconda has been active In the Bingham mining district near Tooele, Utah since 1914 when the company acquired International Smelting & Refining Co. Over the years both custom ores and complex Pb-Zn-Cu ores from the district were milled and smelted at International. In 1948 Anaconda acquired the property that covers the present Carr Fork ore body. Since that time active exploration took place in the 50's followed by detailed geological evaluation in the 60's. Convinced that high grade Cu deposits would be found at depth, a deep drilling program commenced in the late 60?s, with intersection of the ore zone in 1969. Following extensive deep drilling in the early 70?s, a feasibility study was conducted in 73-74 with board approval given Sept. 6, 1974. The 9,000 t/d mine-mill complex was budgeted at $217 MM over a 5 year schedule with start-up in Sept., 1979. The following discussion includes the concentrator and surface facility portion of the budget or approximately $60 MM of the scope. Special emphasis will be made on equipment selection and layout.

Jan 1, 1980

By Don Dodds

Iron Mountain Mine Rehabilitation Project Brief History The Iron Mountain Mine is located in Northern California approximately 12 miles northwest of Redding. The ore body is a large, very dense pyritic intrusion, discovered in 1860, and initially minded for silver. The silver played out quickly and 34 years later the ore body was mined for copper. Copper mining was scheduled to cease in 1939, but WWII prolonged the closure. After WWII, the pyrite ore was mined to produce sulfuric acid. In 1949 when large amounts of cheaper sulfuric acid were being generated by the oil industry the underground mine shut down. Little was done with the site conditions until 1970 when the U.S. Bureau of Mines began monitoring the pH of the effluent. The initial pH readings were around 2.0. This was lower than anyone expected. Laboratory tests showed that when the ore from the mine was submerged in water, the pH of the water would stabilize above 4.0. However, the pH got steadily lower. In 1989 with the ph around 0.7, the U.S. Environmental Protection Agency (EPA) required the owner to build a capture and treatment facility. During this initial period, the majority of the effort was spent on the treatment plant. The relationship between the mine owner and the EPA was basically an adversarial relationship from the very beginning. In 2001, North Pacific Research was hired to upgrade the capture and control facility. The general layout of the Iron Mountain Mine is shown in Figure 1.

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.

By J de Cuyper, N. R. Tipman, G. E. Agar, L. Laré, W. Freyberger

The flotation chemistry of the commercial INCO matte separation process was investigated. The slow cooling of Bessemer converter matte forms discrete phases of Cu2S and Ni3S2 and a Cu-Ni alloy. After magnetically removing the alloy, the Cu2S and Ni3S2 are separated by flotation at pH 12.4 (saturated lime) using diphenyl guanidine (DPG) as both collector and frother. DPG has been used exclusively in this flotation process because of its unusual selectivity for copper minerals. The surface product resulting from chemisorption of DPG onto the Cu2S was identified as the double salt Cu(DPG)2SO4,.CU(DPG)2(OH)2. The adsorption followed Langmuir behaviour up to a monolayer coverage. In the absence of DPG, the rapid adsorption of oxygen by Cu2S in flotation pulps was observed. The surface product was identified as the insoluble basic copper sulfate CuSO4.3Cu(OH)2 with the production of sulfate ion. In the presence of DPG, the oxidation reaction appears to be suppressed. The frothing properties of DPG and commercial frothers were compared. DPG is not a powerful frother. Batch flotation tests confirmed that DPG is a highly selective collector when compared to most sulfhydryl collectors.

Jan 1, 1976

The Penetrating Cone Fracture (PCF) technology 1 is a new method of rock excavation developed by Sunburst Excavation, Inc. of Denver, Colorado. PCF is a rock excavation method which employs tensile breakage mechanisms under controlled conditions to enable the continuous excavation of rock?in underground and some surface applications. The technology has developed rapidly over the last two years to the point where it is now being prepared for commercial application in the mining and civil construction industries. The initial commercial application of PCF will be undertaken at the Perseverance Nickel Mine of Western Mining Corporation Limited in Western Australia beginning in May, 1994.

Jan 1, 1994

By PDF

Previous work has shown that significant, free milling gold values exist in the Ryan Lode ore. This project used pilot scale equipment to estimate the percentage of gold recoverable by gravity methods from the circulating load of a conventional, closed-circuit, grinding mill. The pilot scale flowsheet employed three stages of gravity concentration, hydraulic classification and batch grinding to simulate a full scale milling circuit. 172 kg (379 lbs) of Ryan Lode ore were processed, having a head grade of 4.8 g/metric ton (0.14 oz/ton). Results showed that simple gravity methods are capable of recovering 45-50% of the gold values in a concentrate grading in excess of 3430 g/metric ton (100 oz/ton). Of the remaining gold values reporting to the classifier overflow solids (80% passing 70 microns, 3.1 g/metric ton (0.09 oz/ton)) 89% were recovered from 48 hour bottle roll tests.

Jan 1, 1995

By William D. Leech

Lebanon used a TBM for the firsttime to excavate a tunnel in the country. A main beam TBM, built in 1979, bored the 3.8 m (12.5-ft) diameter by 4,020 m (2.5-miles) Madiq Tunnel. The TBM bored through karstic terrain of dolomitic limestone, limestone and marly-limestone rock having near horizontal beds with more than twelve faults crossing the axis of the tunnel. The TBM also encountered more than six major karst features, filled with various combinations of boulders, clay, void space and water. The excavation through these collapsed-breccia zones drastically slowed the TBM?s progress. When complete, which the Madiq Tunnel is a part, the Kesrouane Water Project along the coast will bring fresh and irrigation waters to the parched and heavily populated region north of Beirut. The paper will describe the tunnel geologic features, karst genius, TBM upgrades and performance, and TBM/karst difficult situations

By Brett Campbell

The San Vicente to 2nd Aqueduct Pipeline?Tunnel project is a raw water conveyance tunnel linking the San Vicente Reservoir (SVR) to the 2nd Aqueduct Pipeline via Rancho Penasquitos Pressure Control Facility (RPPCF). This 58,230 lf long tunnel will be 8.5? final ID, and has four points of construction access. The job is classified into 6 Reaches of tunnel, identified by the dominant geology within the reach. This paper will focus on Reach 3, specifically the measures necessary to drill and blast a 550 lineal foot section of granitic rock tunnel immediately in front of an open face digger shield.

Jan 1, 2008