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By Neville T. Moxen, Stuart K. Nicol, Malcolm D. Engel

Ion flotation is a process in which ions of interest are complexed with a suitable surfactant molecule. A dilute solution containing these complexes is then aerated, under which circumstance the surface-active complex concentrates at the air-water interface and is transferred to a froth. The present work describes some of the phenomenology of this process and experimental work leading up to the design and use of a pilot scale laboratory facility. Early experiments suggest that selective recovery of gold can be obtained in a manner at least equivalent to conventional CIP processing at low capital cost. Under favourable conditions, upgrade ratios of gold ions of the order of 180: l have been achieved from reclaimed residue dam water with as low an initial gold level as 0.2ppm. Successful development of countercurrent ion flotation for concentrating solids-free gold solutions may offer a lower cost alternative to existing gold ore processing technologies, or in more secondary applications such as concentrating dilute gold solutions or heap leach runoff. The technology may also have more generalised applications to other heavy metal processing.

Jan 1, 1990

By A. S. Atkins

The interest in the use of micro- organisms in the leaching of sulphide minerals has been traditionally exploited as a scavenger process for the recovery of valuable metal by- products from waste ore dumps. Environmental concern on sulphur emission from conventional pyrometallurgical plants together with the cost of stack cleaning systems to comply with legislative control also indicate baccerial leaching to offer a low cost treatment for the processing of sulphide minerals. The paper describes the effect and limits of relatively coarse particles on the complete leaching of pyrite and its importance to the practical application in dump leaching operations of sulphide minerals. It has also been demonstrated that static leaching techniques have encouraging economic potential for process plant operations compared with agitated leaching systems.

Jan 1, 1984

By Randal J. Barnes

The nonlinear network optimization algorithm developed in this paper solves the following mine ventilation design problem: find the location and size of all fans and regulators which minimize the overall system power consumption while satisfying all physical, legal, and operational constraints. This work includes the formulation of the problem within the framework of mathematical optimization, the development of the computational theory, and the creation of an efficient solution methodology. The algorithm has been implemented on a microcomputer, and a small but representative example is included. The algorithm presented in this paper has four limitations. First, the optimization process is for a single point in time: the dynamic nature of a mine ventilation system in an evolving mine is not directly addressed. Second, the topology of the ventilation network is required input information. The mathematical algorithm does not optimize the size or location of the mine ventilation airways; however, the post optimality analysis techniques can be used to aid in topological decisions. Third, the problem is formulated using volumetric flow; thus, heat and moisture transfer are ignored. Fourth, the capital cost of ventilation equipment is not included in the formulation.

Jan 1, 1989

By B. F. Buie

In South Carolina and Georgia an area about 20 miles wide situated near the inner margin of the Coastal Plain and extending from the vicinity of Columbia, S.C. southwestward about 180 miles to the vicinity of Macon, Georgia is the principal kaolin-producing area of the world. It is especially important as the world's major source of clay used for paper coating. Essentially all of the land known or likely to be productive of quality kaolin in this area is now owned or controlled by producing companies. The least-fully developed portion is that in the vicinity of Wrens, Georgia which has been explored and developed since 1961. For the two decades following the end of world war II, demand for kaolin increased at approximately twice the rate for other industrial minerals. From 1945 to 1965 production increased four-fold. Since 1965 the rate of increase has been less, but the outlook now is that production and demand will double at least once again before the year 2000. A substantial part of this increased demand has come, and will continue to come, from industrial development, especially in the paper industry, outside the United States. The general effect, in addition to a continuing increase in production in the U.S., will be to cause: 1. Intensive research for development of more effective and more economical methods of beneficiation; 2. Concerted research effort to find an economical way of modifying high-viscosity kaolin so that it can be used for paper coating; 3. More active exploration in the U.S. and overseas, especially for deposits to supply the foreign markets; 4. More intensive study of the geological factors responsible for the accumulation of commercial deposits of kaolin; 5. Some modest rise in price, relative to the cost of other industrial minerals. The effect on kaolin producing region of Georgia and South Carolina will be to cause: 1. Working of progressively lower-grade deposits; 2. An increase in the acceptable thickness of overburden; 3. Mining of deposits farther down-dip, the use of which is now inhibited by large volumes of groundwater; 4. Increased threat of invasion of the kaolin in industry's market by substitute materials; 5. A substantial increase in concern over environmental factors; 6. More attention to be paid to the large opportunity offered for mining of silica sand and other co-products.

Jan 1, 1972

By Konner Horton, Adam L. Bedell, Don Del Nero, Brian Jones

"The City of Atlanta’s Water Supply Program Tunnel project includes a 7,315-m (24,000-ft) long, 4-m (13-ft) diameter, hard rock tunnel. A complex aspect of the project involves connecting five, blind bore shafts to the tunnel in a location close to current drinking water reservoirs. During the supplemental geotechnical investigation following the initial contract award, results from additional borehole geophysics were reviewed. Unfavorably oriented fracture sets forced a change in the original pre-excavation grouting program designed for that site. Real-time grout monitoring and geophysical data were compared to provide assurance that the program, as designed, correlated with the in situ ground conditions. Following grouting, results were modeled, and all grouting data were reviewed to determine if grouting was complete.Project backgroundThe current water supply system operated by the city of Atlanta’s Department of Watershed Management (DWM) consists of four, aged, raw-water pipelines, one of which dates back to 1893. Based on previous assessments completed by the DWM, the entire water supply system is at, or will soon reach, its recommended useful life. As such, the city acquired the Bellwood Quarry in 2006 with the intention to create a water storage facility with a volume of approximately 9.1 billion L (2.4 billion gal) to serve approximately 1.2 million people.The project location is shown in Fig. 1, which is generally in the northwest part of downtown Atlanta, GA. The overall project has been divided into two phases. The Phase 1 project connects the quarry and the Hemphill Water Treatment Plant (HWTP), and the Phase 1 Extension project connects the HWTP to the Chattahoochee Water Treatment Plant (CWTP) and the Chattahoochee River. A 7,315- m (24,000-ft) tunnel with a finished diameter of 3 m (10 ft) connects all three elements. The HWTP location is also where the city’s two most proximate drinking water reservoirs are located."

Jan 9, 2018

By JA Vallejos

High stress underground mining poses a significant challenge to rock mechanics and rock engineering. To overcome theses challenges significative improvements in solutions and best practices of the design and operation of mines under high stress have been developed and implemented. This paper presents certain topics related to the management of high stress for sustainable underground mining. The topics include; the effect of preconditioning techniques (destress blasting and hydraulic fracturing) in the seismic rock mass response to underground mining and the dynamic behaviour of rock support systems. The opportunities associated with research in rock mechanics and practical rock engineering are discussed.

Apr 26, 2022

By Felicia F. Peng

The manganese removal from aqueous solution containing high Mn2+ concentration by adsorption and oxidation was studied using manganese oxide particles as the adsorbent. The operating parameters including pH, flow rate, initial manganese concentrations, and oxidant dosage affect the performance of Mn2+ removal were evaluated in a laboratory packed column. In the multi-column adsorption tests, each additional column doubled the time for complete manganese removal. No further decrease of pH was also observed once it was lowered to pH 4.5 to 5. This finding implied the possibility of complete high manganese removal without further pH adjustment during adsorption. Oxidation of Mn2+ by dissolved oxygen was found to be insignificant for manganese removal for high Mn2+ concentration. Adsorption was the predominated mechanism involved with manganese removal. Extremely low H+/Mn2+ stoichiometry compared to the reported values was measured. These low values suggested that different adsorption mechanisms such as chemisorption other than H+/Mn2+ ion exchange might play an important role at low pH. This paper presents the quantity and explanation of the results obtained for the mechanism of adsorption and oxidation of high concentration manganese on the manganese ore particles.

Jan 1, 1997

By Hans Hamrin

Three drill-blast cycles of 3.1 m advance achieved in one working shift of 7.5 hours at the Holsfjorden Tunnel project in Norway. The tunnel, 5235 m long, with a cross section of 8.6 m2, was completed several months ahead of schedule. This remarkable performance was achieved by a crew of 16 men, using machines specially designed for small tunnel excavation. The integration of drilling and charging into one unit, mucking and transport in another, reduced non-productive time considerably. The average cycle time of 140 min made it possible to complete three rounds in one 7.5 hours shift.

Jan 1, 1987

By J. G. Groppo

A series of performance studies have been conducted using counter-current column flotation to recover a marketable clean coal product from existing preparation plant fine waste streams. The test work was conducted at several preparation plant sites in Kentucky and Virginia and utilized a 0.15m (6 in.) I.D. column that was 5.79m (19 ft.) high. The refuse streams tested included both thickener feed and classifying cyclone overflow with a typical size distribution of 100 mesh X O. The percent solids of the column flotation feed varied from 1.5 to 15% while the ash content ranged from 30-60%. The concentrates produced contained 2-10% ash with BTU recoveries of nearly 90% using 0.12-1.25 kg/ton (0.25-2.5 lbs/ton) fuel oil and 0.12 kg/ton (0.25 lb/ton) MIBC. These results were consistent with or better than results obtained in preliminary laboratory scale column flotation evaluation. Test results from 7 different seams are discussed as well as scale-up relationships utilized to design a full scale installation presently in operation.

Jan 1, 1990

By A. Habibi

A study has been undertaken on two 1.12 m diameter industrial booster fans operating under different blade settings powered by a 1200 rpm motor at the Missouri University of Science and Technology. The fans total pressure varies up to 1kPa forcingup to 25 m3/s through the workings. A pressure-quantity survey has been conducted inby and outby the booster fans with different blade settings. The study uses a variable speed drive (VFD) to determine the effect of rotational frequency on the system. The pressure drop across the bulkheads has been monitored during the experiments. The fans were operated with various blade settings to determine the optimal scenario that maintains the maximum airflow quantity and the lowest power demand at a particular ventilation station. Five scenarios were conducted with different blade setting and mostly with two different speeds. The experimental results show that alteration of fans? speeds by use of a VFD unit can reduce power consumption while maintaining airflow requirements. With the flow rate forced through the mine by the surface fan the blade settings 4 and 5 were determined as possible alternative for the mine ventilation system. In scenario 4, the airflow at the particular ventilation station for a number of speeds is over 20m3/s. The power consumption at 1080 rpm was measured to be 20.1 kW compared to 25.5 kW at 1200 rpm. The operating cost would be significantly less at lower speeds. Scenario 5 is the alternative making use of both booster fans and the main fan in series that meets the minimum airflow requirement at the particular ventilation station along with minimum power consumption. Reducing both booster fans speeds to 1054 rpm results in power consumption of both together dropping to 11.8 kW. Therefore blade setting 5 using two booster fans was determined to be the optimal setting. Separately it was determined that the combination with use of only one booster fan, the West booster fan, running in series with the main fan is the overall optimal scenario. The power consumption of the West booster fan was calculated to be 8.8 kW at 860 rpm with the minimum airflow requirement being met. Computational fluid dynamics is used for analyzing three dimensional flow structures in time domain and calculating the corresponding unsteady pressure fluctuations. The sliding and dynamic mesh techniques were used to study the unsteady flow interaction arising due to the rotation of the fan blades. The numerical predictions of the variables in the form of velocity vectors and contour plots detailing the flow characteristics are then analyzed according to the known physical situation and existing experimental data.

Feb 27, 2013

The Midvale Slag Site covers 300 acres in Midvale, Salt Lake County, Utah. Midvale (population 10,000) is part of the Salt Lake City metropolitan area (population 936,000). Between 1902 and 1971, United States Smelting, Refining and Mining Co. smelted ores on the site to produce copper, gold, lead, and silver. Figure 1 shows a picture of the historical Midvale smelter operations. [ ] When operations ceased, the site was estimated to contain 2 million tons of slag from these operations. The smelter no longer exists. In 1971, Valley Materials, Inc., acquired the site to process the slag into materials for railroad beds and asphalt highways. During the 1980s, the U.S. Environmental Protection Agency (USEPA) raised concerns regarding environmental impacts associated with the historical site operations. The Midvale Slag Superfund Site was listed on the NPL in 1991. The Site consists of two Operable Units (OUs): OU1 covering the properties north and adjacent to former ore smelting operations; and OU2 covering the smelter site itself. OU1 had historically been affected by wind blown slag dust and stack emissions occurring on OU2 and the Sharon Steel site further to the south. These emissions resulted in elevated levels of arsenic and lead in the native soils. The EPA issued the final Record of Decision (ROD) for the OU1 Site in 1995. The OU1 ROD required the implementation of institutional controls for the undeveloped portions of OU1 in order to restrict future land use to commercial/industrial purposes unless additional remediation was performed. Hence, the land comprising OU1 was originally considered in the ROD to be suitable for commercial or industrial purposes without the need for remedial action. However, development of OU1 for other land uses, including residential or recreational, would require additional assessment and probable remediation. The OU2 parcel was remediated by EPA to allow future land development, and the Sharon Steel site was remediated by EPA and deleted from the NPL. PROPERTY TRANSACTION AND REDEVELOPMENT In February 2006, a private development company, Mercer Bingham Junction, LLC. (MBJ) purchased 130 acres of the OU1 property for the purpose of performing environmental remediation, and developing mixed residential and commercial real estate. Development of the property was conducted in cooperation with USEPA Region 8 (EPA), the Utah Department of Environmental Quality (UDEQ) and Midvale City. The guidelines under which residential development could occur were defined by EPA. The 130 acres was to be developed for open space, residential and commercial use as part the Midvale City Bingham Junction development. Figure 2 shows the general layout of the proposed land uses. [ ] In May 2005, MBJ began pre-acquisition due diligence activities to purchase the 130 acres of OU1 north of 7200 South Street, which now comprises the Bingham Junction Development. This included the completion of Phase I and limited Phase II investigations. The Phase II investigations were performed to evaluate arsenic and lead concentrations in the planned residential areas of the site, and to explore the contents of the historic landfill on the property. The historic landfill area was on the far west side of OU1, adjacent to the Jordan River. Soil samples collected during the Phase II investigation showed that the planned residential parcels did not currently meet the criteria established in the Tech Memo and that additional placement of fill or soil excavation would be required for residential development in this area. An evaluation performed by the previous owner of the property, Littleson, Inc., showed similar results.

Jan 1, 2009

By K. Zeidler, T. Schwind

The Fort Canning Tunnel, Singapore, is an approximately 50 feet (15m) wide vehicular tunnel under shallow ground cover that has been constructed according to the principles of the NATM. Its shallow location in soft ground combined with a high groundwater elevation in close vicinity of historically important features called for special design considerations combined with a rigorous monitoring scheme. Surface, sub-surface and in-tunnel instrumentation was installed to monitor the performance of the ground and tunnel support during construction. Comparison of actual reading data with the results from the computer modeling carried out during the design phase is provided in this paper.

Jan 1, 2007

By Jun Ho Lee, Dae Young Kim, Ebrahim Farrokh, Ki Chang Hyun

"The Jinhae Geoje gas pipeline tunnel project is the largest (7.8 km) and the deepest (90 m) subsea tunnel in South Korea. This tunnel will house a pipeline to carry natural gas from the mainland to Geoje Island southeast of the country to alleviate the increased demands for natural gas, especially in the winter season. Tunneling is currently underway using two slurry shield TBMs of 3.5 m diameter. This paper describes the major design elements of the tunneling machines and their performance evaluation. For this purpose, a thorough analysis of geotechnical information was performed to evaluate the tunnel elevation to reduce the risk of tunneling under high water pressure in unstable and permeable rock mass under 9 bar water pressure. TBM specification and TBM performance were also analyzed using different methods, including well-known models as well as a rotary cutting machine test developed in house in Hyundai Engineering and Construction Company. INTRODUCTION High demand for natural gas, especially in winter season was the primary driving factor for the design of the Jinhae Geoje gas pipeline project. This project is located southeast of South Korea between Jinhae district and Geoje Island and runs for over 50 km length. The mid part of this project includes a 3.5 m diameter subsea tunnel consisting of two sections of Geoje to Jiri Island (4.3 km) and Jinhae to Jiri Island (3.5 km). Figure 1 shows the tunnel project location and its layout. Figure 2 shows the geological profile along the tunnel. As can be seen, the tunnel passes mainly through three rock types: granite, tuff breccia, and andesite tuff. This tunnel was planned to be constructed by two face pressurized shielded TBMs and to be lined with a segmental lining of 2.8 m internal diameter. The major challenge for this tunnel is its maximum expected water pressure at the tunnel invert (8.83 bar). At such a high water pressure, the TBMs required special design to ensure they can handle unexpected water pressure and to ensure the risks for the TBM maintenance intervention are minimal. In this regard, a thorough analysis was conducted on the TBM design parameters and geotechnical information to define required TBMs’ design parameters and to identify the safest tunnel elevation. This paper provides a brief overview of the project geotechnical information, TBM selection and its design specification, tunnel elevation selection, and TBM penetration rate evaluation. In this regard, a rotary cutting machine testing equipment was used to perform trial tests on a similar rock type encountered along the tunnel for performance evaluation and optimization."

Jan 1, 2016

By K. W. Grubaugh

Indigenous people are nearly always affected when projects enter their territory. Crop and other asset compensation can help or undermine a project’s progress depending on the approach. When compensation is handled poorly, a technically viable project can get indefinitely entangled by local unrest. Stake holders associated with compensation issues include; the state, the indigenous people, non-governmental organizations, and the developer. Appreciation for the unique perspective of indigenous peoples and the influences affecting them can avert problems and prevent delays. A review of the compensation issues encountered in Ghana during its recent gold boom can assist in avoiding problems associated with handling poor and uneducated people.

Jan 1, 2002

By J. B. Gwiazda

Introduction Thick seams constitute a considerable portion of Polish coal reserves. In producing mines and those under construction, the reserves where the height is more than 4.5 m (15 ft) total about 24% of all the hard coal reserves. The reserves that are under urban and industrial areas can be extracted using stowing methods for surface protection. About 50% of thick seam reserves can be extracted by caving methods. Thick seam mining methods Thick seams are usually extracted by multilift methods. There are some methods of thick seam mining that generally can be divided into caving and stowing methods. The stowing method is more expensive, but must be used when mining to protect surface features. The more known methods of thick seam mining include • extraction of thick seam in ascending order with stowing ; • thick seam mining in descending order with consolidated stowing; • thick seam mining with gob consolidation; • thick seam mining in descending order with roof caving ; • sublevel caving thick seam mining system; and • thick seam mining system using an artificial roof. Thick seam mining with introduction of an artificial roof The most advantageous method of thick seam mining is the method using an artificial roof. The artificial roof usually consists of wire mesh. Such wire mesh must be durable and must prevent small rock fragments from passing through. The mesh is usually made of steel properly protected against corrosion. The artificial roof is placed on the coal floor of the top slice (Fig. 1). Caving rock falls on the artificial roof and is thus separated from the coal. The next slice is extracted under the artificial roof. The producing face of the next slice must progress within 10 m (33 ft) behind the front of the first slice. As the second producing face progresses, the wire mesh moves down on the coal floor and may be used as an artificial roof for the next slice. Thus, one artificial roof allows the extraction of several consecutive slices. Application of the artificial roof allows for clean extraction and reduces coal losses. It also eliminates the hazard of spontaneous combustion. Introduction of the artificial roof has been limited due to a lack of artificial roof laying equipment. Manual laying of wire mesh is a labor-intensive operation, and it delays face progress, resulting in poor productivity. To eliminate these problems, artificial roof laying equipment was designed at the Polish Central Mining Institute. The support and the method of laying operation is covered by a patent. Artificial roof laying powered support To extract thick seams using an artificial roof, four-leg shield supports with lemniscate linkage were developed (Fig. 2). This shield is used in the first top

Jan 3, 1987

By Guosheng Zhan

The Homestake Mine included the open cut and underground workings up to 2,484 m (8,150 ft) deep. The mine ceased mining activities in December 2001 after 125 years of operation. Pumping from the underground workings continued for 18 more months until June 10, 2003. Homestake had completed a comprehensive hydrologic evaluation on post-closure underground flooding prior to the shutdown of pumping. After closure, the mine was selected by the National Science Foundation as the site for the Deep Underground Science and Engineering Laboratory (DUSEL). An interim laboratory facility will be set at the 1478 m (4850 ft) Level. The final facility will be set at the 2256 m (7400 ft) Level or deeper. Pumping from the underground workings began on June 5, 2008 by the South Dakota Science and Technology Authority (SDSTA). During the period of June 2008 through March 2009, the pumping rate increased from 41 L/s (650 gpm) to 81 L/s (1,290 gpm) with an average rate of 60 L/s (950 gpm). As a result, the water level had been lowered more than 95 m (310 ft). It was found that the observed rebound and later decline to date is in close agreement with the model projections. Because of this, the authors of this paper reject claims of a lack of sufficient measurement devices in place and a lack of understanding of the hydrologic system at the Homestake Mine prior to shutdown of pumping in 2003 (Davis et al, 2009). Furthermore, it is believed that this validated model can serve as a useful tool for the SDSTA to manage future underground dewatering for the DUSEL operation. This paper evaluates the hydrologic conditions in the Homestake Mine area and projects the post-closure groundwater rebound and decline due to DUSEL pumping.

Jan 4, 2010

By Donald G. Dahle

Project Payette is a conceptual nuclear experiment under the Vela Uniform program intended to further evaluate the mechanism of seismic decoupling. Vela Uniform is a Department of Defense program to improve this country's capability to detect, locate and identify underground nuclear detonations. This program evolved from recommendations of the Panel on Seismic Improve¬ment, (Berkner Panel), an officially appointed group of noted U. S. scientists. This Panel, taking note of difficulties in detecting the differences between some underground nuclear detonations and some earthquakes recommended a program of increased basic research in seismology. The theory of decoupling, Which involves possible reducing of seismic motion resulting from underground explosions by reducing the coupling or physical linkage between the explosion and the geologic environment, was investigated by Dr. Albert latter and his associates at RAND during the late 1950's. The concept has been further investigated theoretically by scientists of the Lawrence Radiation Laboratory and the Sandia Laboratory. The theory has been tested experimentally under Vela Uniform Projects Cowboy, Dribble and Sterling. The Salmon Event of Project Dribble was a tamped (with the explosive in firm contact with the geologic formation) nuclear detonation 2700 feet below ground in the Tatum Salt Dome. Project Payette, if found to be feasible and if authorized for actual execution, would become a decoupled experiment in the same environment.

Jan 1, 1968

By Andrew J. Regis

Resource figures for bentonite clays are generally based on stratigraphic, sedimentary geologic data and drilling and sampling. Estimates of bentonite resources and/or reserves commonly found in the literature report on bentonite occurrences in specific localities or areas but none on any documented comprehensive estimates of bentonite resources. From 1974 thru 1977 the Bureau of Land Management conducted extensive studies of the resources of commercial grade bentonite in the three state region. These investigations consisted of: 1. Stratigraphic and geologic sampling with supplemental drilling data, followed by geostatistical analysis. 2. Data compiled from a systematic search of county and state records on mining locations, leases and acreage filed for bentonite. Estimates of resources of commercial grade bentonite using industry parameters were calculated from these data sources. It is concluded that there exists from 1.5 to 2.4 billion tons of in-place bentonite in Wyoming, Montana and South Dakota. Assuming a 5 percent annual growth rate for the industry, this would indicate a life of 62 to 73 years.

Jan 1, 1979

By Ingvar Janelid

During recent years, numerous articles have been published regarding theories and practical applications of sublevel caving. The reason is the great interest this method has created through its possibilities of standardizing and mechanizing operations and equipment. Other advantages are that the method can be adapted to orebodies of different shape, size, strength etc., and especially that working conditions can be made safe and relatively comfortable since all work is carried out in drifts. As is well known, the disadvantages or sublevel caving are that ore recovery hardly exceeds 85-90 % if waste rock dilution is to be kept below 20-30 %. Therefore, the main research and development work has been concentrated on parameters which can affect and reduce these disadvantages. This paper deals only with principles and problems which apply to large, massive orebodies. The problems with narrow, vertical or inclined orebodies are so different that they require a special handling. In my opinion, the intense research and development work during recent years, combined with practical experience, has given enough knowledge of the influence of different parameters, so that normal sublevel caving can be efficiently planned.

Jan 1, 1975

By Charles H. Arnold

This topic addresses historic and current techniques of excavating, supporting and lining tunnels of 4 m (13.1 ft) and smaller. Special considerations relate to the economics of working in close quarters and the sizes of tunnel which achieve the required facility in the optimum economic manner are discussed. The excavation discussion includes TBM, conventional and special techniques for hard rock, soft ground, subaqueous, free and compressed air tunnels. Internal and external support methods discusses timbering, steel ribs, bolting, strapping, shotcreting, grouting, and freezing. Lining methods include cast-in-place concrete, concrete pipe, segmented linings, shotcrete, and others.

Jan 1, 1981