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By Leslie M. Burnside, Gene E. McClelland, Roy R. Cellan

Revegetation of neutralized heap leach material in the arid environment of the Great Basin represents a challenge of avail­able technology. The chemical and physical environment of spent and neutralized ore is inhospitable for germination and establishment of desirable long term vegetation. Common soil amendments were tested to dete1mine if the heap material could be made more conducive to plant growth. Decommissioned heap material profile samples were collected and reconstructed in columns at bench scale. The column profiles were amended and subjected to three leaching regimes, and representative meteoric conditions. The soil amendments provided positive results for ameliorating the heap material limitations and providing a medi­um conducive to plant growth. The bench scale study also pro­vided insight for the future of heap leach planning and design with successful reclamation in mind at the forefront.

Jan 1, 1998

When longwall equipment is being specified, a nominal capacity is generally given on which to base the design of the various face and out-bye systems and components. This capacity generally comes from a nominal annual capacity requirement based on realistic utilization rates. From illustrative examples of simple system simulation, this paper sets out to show that a single nominal capacity is not sufficient to size the different systems. The manner in which the Longwall is operated and the overall system configuration and availability can have a significant impact on overall productivity.

Jan 1, 2008

By Glen L. Black

Choosing a mining method for an underground orebody is a complicated and often iterative process. Advances in technology have given design teams an array of possibilities for methods and equip¬ment. Hecla Mining's discovery of the deep Gold Hunter ore body challenged the staff at the Lucky Friday Mine to determine the optimum mining method. Taking an ore body from prospect to production requires traditional resource characterization. This includes drilling, delineating and modeling. Developing the mining plan is an evolving process, changing with each new piece of in¬formation as the project progresses through exploration and development. The Gold Hunter deposit is a steeply dipping vein system in the Wallace Formation of Idaho's Coeur d'Alene mining district. Gold Hunter is a misleading name for the ore body. The vein is a silver-rich, lead-zinc deposit with only traces of gold. The Gold Hunter ore body is located about 1.6 km (1 mile) north to northeast of Mullan, ID. The ore body is mined from the Lucky Friday Mine, located 0.4 km (0.25 miles) east of Mullan. Mining began on the vein from an access drift driven from the Lucky Friday Mine's 4900 level. Production from the ore zone is projected to be 771 t/d (850 stpd). The Gold Hunter ore is combined with Lucky Friday ore and milled in the Lucky Friday mill. The combined ore boosted Lucky Friday's 1998 silver production from 62.2 t/a (2 million oz/year) to more than 124.4 t/a (4 million oz/year).

Jan 1, 1999

By M. Jack Snyder

The problem of effective utilization of fly ash has been given wide attention for a number of years. Although the effort devoted to the problem has led to some applications of demonstrated usefulness, the full utilization of fly ash has been held back by lack of concerted research and development activity, by lack of effective dissemination to potential users of fly ash of the knowledge that is available from laboratory and field studies, and by the obvious variability of the product. Because of the variability in fly ash from one power plant to another and from time-to-time in the same plant, specifications have been set up defining compositional or property limits within which a fly ash must fall to be used in certain applications. This paper discusses the bases for such specifications and examines them in the light of recent research on the characterization of fly ash. Other limitations and restrictions on the use of fly ash and what is being done to overcome them are also discussed.

Jan 1, 1968

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, BRADLEY BENNETT, Patrick Zhang

The purpose of this work is to develop a conceptual recovery process for thorium dioxide (ThO2) from its primary source, monazite. The study-level design presented in this paper represents an economically viable method for conducting ThO2 extraction from monazite ore while also recovering byproducts that include P2O5 and other rare earth element oxides rather than producing unnecessary waste streams. Three key points to note in the development of this process design are: (1) the process economics relied heavily on recovery of rare earth byproducts, (2) the thorium handling portions of the process could effectively be segregated from the rare earth and phosphate handling portions of the process, and (3) the thorium and uranium content in waste streams should be carefully managed and eliminated where possible.

In recent years, Computational Fluid Dynamics, CFD, has been commonly utilized in the mining industry to model the fluid flow behavior in underground mine workings. This paper uses CFD modeling to simulate the airflow behavior in underground crosscut regions, where brattice sails are used to direct the airflow into these regions. Brattice sails are cost effective ventilation control devices for temporary or permanent use in underground mining. They can be used to deflect air into the unventilated areas such as crosscut regions. Their design and installation is a fundamental issue for maintaining a sufficient supply of fresh air and achieving effective air circulation and contaminant removal. At the same time, they should have little impact on the mine ventilation system. This paper presents the results of a two-dimensional CFD model, which examines the effects of brattice length on fluid flow behavior in the crosscut regions. The results of this study will assist in understanding the ventilation air behavior and in determining the optimum size of brattice curtain (sails), which provide a highly effective contaminant removal from the unventilated mine areas. This, in turn, helps the mine ventilation designers to meet the mine safety requirements.

Jan 1, 2009

By J. H. Field

The sulfur dioxide emitted in low concentrations in flue gases from the combustion of sulfur-containing coals and fuel oils is a significant factor in contamination of the atmosphere with sulfur dioxide. A review of methods for treating gases containing high concentrations of sulfur dioxide shows that they are seldom satisfactory for purifying flue gases. Processes developed specifically for treating flue gases using liquid absorbents are costly and may cause localized pollution, because the cooled flue gases can settle in the vicinity of the stack. Bench-scale research is being conducted to investigate the use of dry absorbents for sulfur dioxide removal at temperature levels of about 250°- 300° F. and 600°-650° F. Alkalized alumina has been found effective for treating simulated flue gas and Is regenerable by hydrogen, carbon monoxide, or producer gas. Other metallic oxides have been tested as absorbents also. Chemically impregnated activated carbons removed sulfur dioxide from the gas at 265° F. Vanadium pentoxide is effective as a catalyst for oxidizing of sulfur dioxide in the simulated flue gas at temperatures lower than have been used commercially for gases with higher concentrations of sulfur dioxide. Conversions of sulfur dioxide to trioxide wore studied as a function of temp- erature over a range of about 570° to 750° F.

Jan 1, 1959

By L. Neuman

Reclamation and permit applications for mines tend to be very detailed and complicated documents. Depending on its complexity, the application may have to be reviewed in detail for water quality, water quantity, wetland and upland habitat, wildlife issues, waste disposal, historical and archeological significance, other environmental factors, and financial surety sufficiency. To reduce review time and cut costs to the applicant, this paper identifies the most common mistakes that can lead to delays in the application process.

Jan 1, 2004

By D. Robert Weir, M. J. H. Ruscoe, R. M. Berezowsky, M. A. Clegg

The metallurgical processing involved in the produc-tion of the new Canadian one dollar coin is reviewed starting with the hydrometallurgical production of pure nickel powder, followed by the powder metallurgy process for the production of nickel strip and coinage blanks, and concluding with the Aureate bronze electroplating and heat treatment procedure. Coinage requirements are then reviewed with regard to economic, public acceptance, and service requirements. Finally the properties of Aureate nickel coinage are presented in the light of the many and varied coinage requirements, and it is concluded that the new Canadian dollar coin exceeds the requirements admirably.

Jan 1, 1990

By H. V. Fairbanks

The following processes were investigated using ultrasonic treatment in mineral recovery: (1) cleaning coal from coal slurry ponds, and (2) extracting precious metals from tailings and other sources. The treatment entails the production of a water slurry of the material containing the mineral which is made to flow over the vibrating surface of the ultrasonic treatment unit. The vibrations transmitted into the slurry break up particle agglomerates and also produce a scrubbing action on the surfaces of the particles. The treated mineral particles were found to have increased settling rates, better compaction, and more rapid water drainage.

Jan 1, 1990

By R. K. Mehta

Stirred ball mill feed used for ultra-fine grinding application requires fine size separation step in order to avoid over-grinding. This paper presents the selectivity curves obtained for oil shale and complex sulfide are using 460 mesh (30 micron) Derrick vibrating screen. Interestingly, the selectivity curves generated from the experimental data were monotonic increasing selectivity for oil shale but not monotonic increasing for sulfide ore. These non-monotonic increasing selectivity curves were similar to the mechanical air separator fishhook selectivity curves described by Luckie and Austin. A 2 stage classification in series model describing the fishhook selectivity curve has been used in proposing the classification mechanism for fine vibrating screens when heterogeneous multicomponent sulfide are undergoes size separation.

Jan 1, 1992

By Eugene R. Palowitch, Albert W. Deurbrouck, Thomas H. Parrsons

INTRODUCTION Hydraulic concentrators utilize the physical characteristics-size, shape, and specific gravity-of particles suspended in a fluid medium to effect a concentration of desired quality. Fine-coal concentrators include generally those devices which are used to clean roughly 3/4, in. (9.5 mm) top-size coals. While this size designation is somewhat arbitrary, it is consistent with current practice although some fine- coal concentrators can treat coarser coals effectively. A variety of devices have been and are currently being used to wash fine coals and include: dense media cyclones, wet concentrating tables, hydrocyclones, jigs, spirals, launders, and upward-current classifiers. As launders and upward-current classifiers have been replaced by more efficient devices, they no longer warrant consideration as fine-coal washers. And as fine-coal jigs were addressed with the Baum jig under Part 1, Section 2, and heavy media cyclones and hydrocyclones were addressed under Part 2, Section 1, of this Chapter, only the wet concentrating table and the spiral concentrator will be discussed here. WET CONCENTRATING TABLES History The current wet concentrating table evolved from continuous belt concentrators which utilized a flowing film of water to recover heavy metals. In these devices the heavier concentrate moved up the inclined plane of the belt while the lighter impurities were washed away by water flowing down the belt. The natural outgrowth of the continuous belt concentrator was the vanner, a vibrating endless belt which was first developed about 1860 by Hartwig. Later models of the vanner, such as the Frue, incorporated oscillation in a plane transverse to the direction of the water current. Excellent descriptions of these washers are found in The Cleaning of Coal, by Chapman and Mott.80 Further development of tables included the circular stationary table (Linkenbach), the multiple round table (Anaconda-Evans), the bumping table (Campbell), and finally the differential-motion table which is now used extensively for cleaning fine coals.

Jan 1, 1991

Narrow vein mining, with enough challenge and also where the cutting edge technology can be applied, is still a very important and exciting portion of the mining industry. Based on the deposit characteristics, the most flexible mining method, cut and fill, has been being tested mining this high grade Northern Nevada property, Hollister, since the year of 2008. In the last three years, 254,000 tons of ore were hauled out of the portal and 23,000 feet of development were excavated underground with the winning of several safety and environmental awards. Together with mine geology, the essential segments include mining cycle, ground control, ventilation, grade control and backfill method in cut and fill stopes were covered in this paper.

Jan 1, 2012

By James D. Bliss

Evaluation of data for three engineering variables-absorption, bulk specific gravity, and freeze-thaw durability (350 cycles)-was made for quarries in carbon- ate rocks in Oklahoma that supply aggregate. It was found that lower Paleozoic carbonate rocks (Cambrian through Devonian) are likely to make a better quality aggregate than upper Paleozoic (Mississippian to Permian) carbonate rocks. In addition, freeze-thaw durability can be forecast from absorption and is exemplary for lower Paleozoic carbonate rocks.

Jan 1, 1999

By David R. Klug, Chris Gause, Troy L. Page

The Inter-Island Tunnel is one of two undersea tunnels which are part of the Boston Harbor Clean-Up Program. The tunnel is 7.7 km (25,160 ft) long, bored to a 4.3 m (14 ft) diameter in the Cambridge Argillite Formation and was finished to a 3.5 m (11.5 ft) diameter final concrete lining. The owner is the Massachusetts Water Resources Authority (MWRA) who is a regional authority responsible for overall design and construction. The tunnel's primary purpose is the transport of untreated effluent from Nut Island facility in Quincy, MA to the new treatment plant at Deer Island. Two sludge lines are installed for the transport of sludge from Deer Island to Nut Island. During construction the contractor encountered fault zones, fractured strata, and soft ground tunnel sections which liberated more ground water than was originally anticipated by the project designer. Ground water was controlled during mining and the placing of the final lining. The final lining of cast-in-place concrete had to be backfill grouted to cut off water inflows and provide contact for equal tunnel loading which is critical in long-term design. This paper deals with an engineered backfill grouting system which was the first of its type to be used in North America. It discusses the geological conditions encountered, the design criteria used in the evaluation process, and an indepth review of the various system components. It demonstrates how contractors can use knowledgeable and professional industry suppliers to solve difficult construction problems.

Jan 1, 1999

By T. L. Brekke, T. R. Howard

Stability of an underground opening can be defined in several ways. To geologists and engineers that are used to working in geological environments where the major parts of the works after careful scaling can be left unsupported during the construction period as well as during operation, any rock mass behavior that requires reinforcement, support or lining may be regarded as a stability problem. To colleagues excavating underground openings in geological environments that require continuous use of reinforcement or support and lining "stability problems" are often associated only with those parts of the work where "standard" construction procedure and method of reinforcement or support and lining is inadequate, and special measures therefore needed. In either case, a major objective is to assess the stability problems correctly -as far as possible at the planning stage -- and choose methods for excavation and reinforcement or support that will bring the opening safely and as economical as possible through the problem areas. INTRODUCTION It is not uncommon that stability problems associated with faults or seams have been described as "unexpected." This term has unfortunately been used to indicate that no one knew that the fault or seam existed prior to excavation. A careful review of documented cases where serious stability problems have occurred revealed that the existence of these zones most often was known, but that their behavior was incorrectly assessed prior to or during construction. Miscalculations have been made in terms of the type and magnitude of loads that developed, and in particular in terms of the time-dependant behavior.

Jan 1, 1997

By Hyung Jeek Kim, Jongmin Joo, Jonguk Kim, Jai-Woon Moon, Kyeong-Yong Lee

"Co-rich ferromanganese crusts (Fe-Mn crusts) distributed on seamounts in the western Pacific are potential economic resources for cobalt, nickel, platinum, and other rare metals in the future. Evaluation and selection of a mining site can be established based on abundance and grade of Fe-Mn crusts in the site as well as topography that should be smooth enough for mining operations. Therefore, acquisition of shipboard echo-sounding and acoustic backscatter data are prerequisite to the selection of potential mine sites in addition to visual and sampling operations. Acoustic backscatter data can be used to locate crust-covered areas on a regional scale with the understanding of acoustic properties of crust through its correlation with visual and sampling data.During an expedition that took place from January to March 2014, KIOST collected geophysical and geologic data to assess the resource potential for Fe-Mn crusts on three seamounts (guyots) in the Western Pacific. In OSM11, one of the three surveyed seamounts, three camera tows were performed to observe the distribution of Fe-Mn crusts on the summit and slopes of the seamount. Although sediments of various thicknesses generally cover most of summit region of OSM11, several regions with high backscatter signals occur on the periphery of the summit. The occurrence of Fe-Mn crusts, observed during the camera tows, on those high backscattered regions suggests that the backscatter signals of shipboard multi-beam sonar can reflect changes in the geology of the seafloor from sediment layer to Fe-Mn crust deposits. The Fe-Mn crust deposited around the summit region is worthy of notice because of its topographic characteristics, including shallow depth, flat or gentle inclined surface, and smooth relief, which are more suitable for mining operation compared to the flanks of seamount."

Sep 1, 2014

By K. N. Han, H. C. Cho, R. Kim

"As an extension of the work on the effect of OH- on various cations in hydrometallurgical systems, the effect of Cl-, Br-, I- and CN- on cations such as Ag+, Cd2+, Hg2+, Cu+, Cu2+, Co2+, Zn2+, Pb2+ and Sn2+ has been examined in detail. The Newton-Raphson technique has been used to determine the amounts of various metal species as a function of the concentration of anions. Some practical implications of various metal complexes in metal separation and removal from solutions have been examined and discussed.IntroductionUnderstanding the role of anions in hydrometallurgical processes often determines the success of an operation. The successful choice of concentration and type of anions not only leads to an effective extraction and removal of metals (Esmaeili et al., 2005; Brbooti et al., 2011; Wei et al., 2005; Jeppesen et al., 2009; Al-Tarazi et al., 2004), but also to assisting effective separation of various metals, whether it is a solvent extraction, ion exchange operation or even a simple precipitation (Farha et al., 2011; Sevenich and Fritz, 1983; Rashid, 1974).This paper continues the discussion of the role of anions in hydrometallurgical systems beyond the role of OH-, which was the topic of a previous paper (Kim et al., 2014). Table 1 lists various anions that are frequently used in conjunction with metal ions to be selectively separated or precipitated. As seen in the table, many anions are used frequently in hydrometallurgical practices. Some of the more frequently used anions include OH-, SO4 2- and CO3 2-. The halogen elements, Cl-, Br- and I- , as well as CN-, are also used in hydrometallurgical applications, especially in relation to noble metal recoveries (Meng and Han, 1994; Zhang et al., 1996; Sun et al., 1996; Starovoytov et al., 2007)."

Jan 1, 2015

By Anita Wu

"GENERAL BACKGROUND/CONTEXT The £300 million Bond Street Station Upgrade project will provide essential congestion relief and step-free access to an important interchange and destination station in the heart of the London Underground network. In 2010 London Underground (LU) let a design & build contract to Costain Laing O’Rourke (CoLOR), with the works to be completed in early 2017. CoLOR’s lead designer is Halcrow-Atkins JV (HAT). The station upgrade works comprise the following principal elements: •,A new satellite ticket hall on the North side of Oxford Street •,Two additional escalators and stairs providing congestion relief to the Jubilee line platforms •,Four lift shafts to provide step-free access between the different levels of the station •,Additional stairs to Central line platform level •,Tunnelled connection to the Crossrail station immediately to the south •,Connecting passageways, including ten connections to existing station tunnels. To achieve this, an existing property at 354-358 Oxford Street has been purchased and demolished, and the basement deepened to make provision for the new ticket hall. From this basement two circular shafts have been sunk, providing construction access for the tunnelled passages and lift and escalator shafts. The tunneling is principally in the London Clay stratum, which is widely recognized as a favorable tunneling medium, although the deepest parts of the works extend into the Lambeth Group strata which consist principally of stiff clays at this level but also contain water-bearing sands. The majority of tunneling has been carried out using mechanical excavation and sprayed concrete linings but other techniques have been used in areas where SCL is not practicable.A key challenge for design and construction of the works has been spatial constraint, in particular due to: •,The existing underground station layout •,The Limits of Deviation for the works •,The small construction site at 354-358 Oxford Street •,Overlaying Third Party assets including Listed buildings, sewers and water mains."

Jan 1, 2016

By W. Ghyoot, J. Boonstra, H. Dijkman, C. Buisman, M. Picavet

Paques and Umicore have demonstrated the feasibility of biological treatment of the highly complex Hoboken wastewaters in a1 m3/h pilot plant at Umicore Precious Metals, Hoboken, Belgium. In the first step arsenic was precipitated from copper smelter effluent as As2S3using biogenic produced H2S. Other metals such as copper, lead and cadmium were also removed as MeS to concentrations well below the discharge levels. Subsequently, sulfate and nitrate were removed to low concentrations (<300 mg/l and < 5 mg/l respectively) in high rate engineered bioreactors. Sulfide produced in the sulfate reduction process was recycled to step 1 for metals precipitation. Selenite/selenate was partly removed in the sulfide precipitation step, whereas the excess was biologically reduced and removed as selenium to concentrations <0.2 mg/l.

Jan 1, 2003