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By Ralph B. Peck

Exploration The technology of underground construction and particularly of tunneling, both now and in the future, starts with knowledge of the properties of the medium surrounding the tunnel. Although we are trying to develop machines that can excavate tunnels independently of the properties of the medium, and although we may achieve some success in this direction, we seem always to be brought up short by a paradox: With increasing sophistication of machines and with increasing complexity of construction jobs, our methods are likely to become more sensitive rather than less sensitive to changes in the medium. I suspect that the need for more precise knowledge of subsurface conditions in advance of construction will increase rather than decrease as time goes by. In the recent anniversary issue of Engineering News Record, Probing the Future, Senior Editor Bill Jacobus prophesies highly sophisticated devices to probe the unknowns of the earth's soil and rock materials. He envisions that "drill holes to obtain borings will give way to rock-melting coring devices". He may be right; it is hard to argue the accuracy of predictions of the future. It seems to me more likely, however, that the rock-melting probe will be simply one more in

Jan 1, 1974

By A. Afrouz, F. P. Hassani

The types of bulkhead that contain backfill in stopes under various pressures and mining conditions are outlined. Conventionally adopted theoretical and empirical techniques were integrated in the design and construction of each type of bulkhead utilized underground. Methods to monitor the performance of bulkheads are discussed.

Jan 1, 1993

By A. K. Ghose

The increasing application of roadheading machines in the coal industry has prompted the development of an appropriate selection methodology for such machine applications in specific locales. Accurate geological sections and comprehensive rock testing are required for all machine tunneling. Using suitable geotechnical parameters and index tests, sensitive both to excavability and standability of the strata, a classification scheme has evolved to help evaluate the rock mass vis-a-vis application of a given weight-class of roadheading machine. The classification parameters include point load index, brittleness, abrasiveness, average crack density, and ground water, which with assigned numerical ratings, lead to a quantitative global rating of the rock mass. For each rock mass class, the selection of an appropriate roadheading machine is recommended. The paper illustrates the application of the rock mass rating system and also describes simple index tests for evaluating the classification parameters for brittleness and abrasiveness. Manuscript not received in time for publication.

Jan 1, 1983

By Luis Pommier

The requirements of metals by modern society have created big challenges for mining engineers minerals processing engineers, metallurgical engineers and economists to produce these metals economically from mineral deposits which contain, with time, less and less value. The advances of science and technology allow, today, the exploitation of mineral deposits which only few years ago would not have been considered economical. However, there are limitations both on the minimum grade of recoverable values contained in the ore to be fed to a mill or on the concentrate to be smelted, and on the maximum content of "impurities" i.e. chemical elements which are difficult or expensive to refine from the ore, from the concentrate or from the metal. It is also known that the cost of treatment in a mill or in a smelter, for unit of metal contained in the ore or in the concentrate, increases as the grade of the recoverable values contained in them decreases and also if the content of impurities increases. In order to work a mineral deposit economically it is necessary to ensure not only that it has more than a minimum content of values, less than a maximum content of impurities and that there exists a good up-grading or metallurgical process but also to ensure that the opti-

Jan 1, 1971

By Irwan Halim, Bhoshaga Mitrran Ravi Chandran, Kevin Huynh

Tunnel segmental lining design constitutes a significant iterative process where modeling and numerical analysis are factors in deciding the number of segments, their dimensions, gasket placements, as well as the locations of dowels and bolts. Consequently, these modifications lead to revisions in the final drawing details. However, the current tunnel engineering practices lack systematic solutions that effectively bridge the gap between the iterative design process and efficient visualization of completed drawings due to the time- consuming nature of redrawing. This paper presents a pioneering application of AI-driven solutions including using Autodesk's API, for the Northside Interceptor Tunnel (NSIT) Project. It showcases the automation of drawing design and the real-time visualization of modifications, thereby streamlining the drawing process.

Jun 23, 2024

By David Conover

The El Boleo Copper Project is currently in the final design stages for development of a 3-MM-tonne/yr underground copper mine located in Baja California, Mexico. The nearly horizontal mineralized zones are amenable to exploitation by conventional mechanized coal mining technology using continuous miners, shuttle cars, and belt haulage. The mine design resembles a typical full-extraction coal mining operation utilizing a sequence of mains, sub-mains and production panels. Due to numerous faults, mining will be conducted as several small adjacent mines accessed through adits from large arroyos cutting through the mine area. Up to four seams may be mined in some areas with a maximum overburden depth of about 250 m. The ore zone is relatively weak and plastic, subject to extensive creep over time. The mine workings will pass through areas of historical shortwall mining panels where the ground has flowed into old entries and gob areas, and then reconsolidated. A small test mine was developed to evaluate mechanical cutting performance, roof-bolt anchorage capacities, roof and pillar stability and caving behavior. In-mine measurements were combined with two- and three-dimensional FLAC models to evaluate alternative development and production pillar designs. The paper will discuss the various factors influencing ground stability at the El Boleo project and the strategies employed in developing a suitable ground control design.

Jan 1, 2009

By S. Hardcastle

Kidd Creek mine has recently completed upgrades of its primary ventilation systems enabling it to maintain a delivery of 1200 m3/s to continue mining ore zones extending to over 3000 m below surface. Following these upgrades the mine initiated a multi-stage review of their ventilation usage. The focus of these reviews, ranged from a brainstorming session of invited experts, through an evaluation of production plans to a detailed analysis of production data to determine if the ventilation system could be run more efficiently, thereby reducing the mine?s power consumption and associated operating costs. The initial review identified 1500 kW of installed fan power that could be eliminated from the primary ventilation system. The benefits of the subsequent analyses, so far, are not as measurable. The second and third analyses, respectively using long range production plan data and historic production data to determine ventilation requirements based upon diesel equipment, did not agree. Both were shown to have limitations, the future based analysis underestimating, and the historical analysis overestimating the requirements. Regardless of the failings of each method, important outcomes were achieved from the detailed analyses, namely, the ability for a mine to meet a forward analysis prediction of airflow depends on its ability to adjust the ventilation to meet the dynamic nature of the mining process. Also, to minimize total ventilation requirements, a mine must regularly redistribute its airflow; this not only reduces the total volume requirement but also increases the variability of the delivered flows which can provide further operational savings. Since the detailed analyses, the Kidd Creek mine has implemented a more frequent ventilation review and redistribution procedure; consequently, it now operates with an average delivery of 930 m3/s, which is 23% lower than in 2005 at the start of the review process.

Jan 1, 2009

By Eric Gilmore, Ron Tudor, Gregory E. Korbin, Bill McCormick, Brad Bush

INTRODUCTION Las Vegas has recently been termed the “Construction Capital of the Country”. It has also been acknowledged as the fastest growing city in the country for several years running. The rapid growth improves the economic picture of the region but it also imparts unusual demands on the area’s infrastructure. In 1994 the Southern Nevada Water Authority (SNWA)was working on a master plan to address the rapid growth. A long range analysis revealed the need for additional water treatment capacity and delivery systems. Short term projections showed that the current system would reach capacity in the summer of 1997 with the possibility of demand exceeding the supply. The River Mountains Tunnel #2 is part of a $150M scheme to quickly upgrade the system to meet the short term demand, improve the overall system operation and allow for a smooth transition into the larger additions being planned for the future. The SNWA selected Carollo/Black & Veatch (CBV) to provide detailed design and construction management for the upgrades. The River Mountains Contracts consisted of five separate contracts broken out separately to stream line a very aggressive (just 34 months) design and construction schedule. Necessary work included four miles of excavated and lined tunnel, connections from existing pipelines to and from the new tunnel including large diameter (to 3.66m(144 in)) valves, a 18 927cu m (5 million gal) regulating reservoir, a surge tank and a 170 343cu m (45 million gal) reservoir to add additional storage to the system. Notice to Proceed was given to Kajima Engineering and Construction (Kajima) on May22, 1995 for the construction of the River Mountains Tunnel #2. The design called for a tunnel to be driven 6070m (19 915ft) in rock and lined to a finished diameter of 3.71m (12.17ft).Excavation began on December 14, 1995 and holed through on April 30, 1996. Lining began on June 25, 1996 and a notice of Substantial Completion was issued on December 13,1996. This paper describes the measures taken to complete the tunnel in 18 months from Notice to Proceed to Substantial Completion. THE RIVER MOUNTAINS SITE The River Mountains are a low range of rugged mountains separating the Las Vegas Valley from its main supply of water, the Colorado River at Lake Mead. They are volcanic in origin and the harsh desert environment has left them as expanses of exposed bedrock rising 305m (1000ft) above the valley with little or no vegetation. An existing 3.05m (10ft)

Jan 1, 1997

By Joel Lenz, Warren Hood, Jackson Jenkins

Whole ore or other process streams are being transported from mines to remote processing facilities for multiple reasons, such as improved project economics, maximum utilization of capital, and minimization of environmental risk. Case studies will be presented from a variety of operations. Glenbrook Nickel processes ore from their deposit and receives ore from New Caledonia, crushes and dries the ore, and transports it inland to the smelter. The Mule Canyon and Rosebud ore bodies truck-haul their ores to the Lone Tree and Twin Creeks processing plants. Pegasus Gold hauls their Diamond Hill ore to their Montana Tunnels facilities, and Sierrita pumps solution to an existing tank house 8 miles away for electrolytic recovery.

Jan 1, 1998

By M. Alnot, J. A. Mielczarski, J. J. Ehrhardt, J. M. Cases

The flotation behavior of minerals depends on the balance between hydrophobic and hydrophilic species present at the surface of the minerals. The direct characterization of the interfacial products formed by the interaction of water and an aqueous solution of amyl xanthate with chalcopyrite, tetrahedrite and tennantite (the two former contain antimony and arsenic) were carried out by X-ray Photoelectron Spectroscopy (XPS) and infrared (IR) reflection spectroscopy. The experimental data collected from in-situ (IR ATR) and ex-situ (XPS, IR External Reflection) measurements have let us determine the types of the adsorption products and to propose mechanisms of interaction between the aqueous solution of surfactant and surface of the investigated minerals. It is shown that two major processes take place at the mineral interfaces: (i) the interaction with water and oxygen resulting in the formation of the oxidation products which are mainly hydrophilic (but also a hydrophobic product was found), and (ii) the adsorption of xanthate producing different types of hydrophobic surface products. The results obtained show differences in the composition of the outermost atomic layers of the investigated minerals which obviously will produce differences in the flotation behavior of these minerals. This work forms a good fundamental basis for a better separation between copper minerals containing arsenic and antimony, and chalcopyrite.

Jan 1, 1995

By F. Duan, W. G. Pariseau, C. S. Schmuck

Three dimensional comparisons between calculated and measured displacements in the hanging wall of a rock mechanics study region at the Homestake Mine show correlation coefficients of 0.7 or higher. Two and three dimensional back analysis of the data lead to different scale factors for determining rock mass strengths and moduli from laboratory values and seemingly to different rock mass properties. A simple analytic model suggests that indeed not only are there two independent scale factors, one for strength and one for moduli, but that there is a logical relationship between the scale factors obtained from two and three dimensional back analyses of the same mine measurements. The three dimensional modeling procedure implemented in the finite element code UTAH3 thus seems to have a realistic potential for investigating underground hardrock mine questions not amenable to two dimensional analysis.

Jan 1, 1987

By Kirk Conway, Richard L. Unger

The U. S. Bureau of Mines conducted a research project to analyze the design of underground mining equipment with respect to ease of maintenance and maintainer safety. The work included a review of maintainability design literature, an analysis of maintenance related accident data, field reviews of equipment designs, and interviews with mine maintenance personnel and equipment manufacturers. Based on the findings, a set of maintainability design recommendations have been prepared. The final recommendations document includes maintainability engineering information for equipment designers, as well as a buyers' guide to aid purchasers of mining machinery in evaluating the maintainability of equipment.

Jan 1, 1992

By L. A. Obasi, C. Obasi

Investigations were carried out to determine the effects of changing metamorphic conditions on the formation of magnetite from the Itakpe iron ore deposit. Various magnetite grain sizes from ferruginous quartzites from different zones were determined and analyzed statistically. The results reflect the reaction of mineral individuals. In particular, the granulometry of magnetite changed with changes in the mineral formation conditions in the deposit and correlate with the mineralo-geochemical zones. This is interpreted as part of a readjustment of the mineral to the prevailing conditions. Because granulometry is a prebeneficiation parameter, this work will be, no doubt, of importance to the exploitation and beneficiation of the quartzites and rich ores.

Jan 1, 2000

By Anthony J. Ranalli, Florentino B. Maestas, Katherine Walton-Day, Richard W. Healy

Water movement and water chemistry were monitored in the unsaturated zone at two sites in fluvial tailings deposits along the Arkansas River near Leadville, Colorado. One of the sites was remediated by the incorporation of lime and biosolids into the soil. Preliminary results, based on data collected during the 11 months following remediation, indicate that differences between the two sites can largely be attributed to heterogeneity of the deposits. Remediation has increased the alkalinity in the upper soil zone, but as of yet, there is no indication that soils at depths greater than 30 cm have been affected.

Jan 1, 2000

By Richard Switalski, Thomas Scotese, James Morrison, Randall Essex

OVERVIEW Like many older metropolitan areas across the U.S., the Greater Cleveland area is served by a combination of separate sanitary sewers and combined sanitary-stormwater sewers. In 1966, a Master Plan was implemented by the Northeast Ohio Regional Sewer District (District) to minimize pollutant overflows into adjoining Lake Erie and its tributary rivers and streams, that would occur during wet weather events. One component of the Master Plan was to reduce the load on combined sewers by constructing new conveyances to intercept separate sanitary flows and convey them to upgraded regional waste water treatment plants for priority treatment. As part of a 15-year program to construct 74 km (46 miles) of new interceptors, the West Leg Interceptor (WLI) Project intercepts flows from four decommissioned waste water treatment plants (WWTPs), and conveys those flows to the new Southwest Interceptor (SWI), which conveys the flows to the Southerly Treatment Plant, a tertiary level treatment facility. The WLI Project was built in sections to permit decommissioning of the WWTPs as each segment of the interceptor system was completed and put into service. Flows from the first of the four WWTPs was converted to the WLI in November, 1992; the final connection was achieved in July 1994. The WLI comprises 9.1 km (5.7 miles) of 21 to 29 m (70 to 95 ft) deep mainline interceptor tunnel, four vortex drop structures, approximately 2 km (1.3 miles) of shallow tunneled connector sewer to the mainline, approximately 2.9 km (1.8 miles) of open cut connector sewers, five construction work shafts (not including one work shaft constructed under SWI Contract 6 at the north end of the WLI), and 15 access shafts.

Jan 1, 1995

By A. G. Journel

Few Earth Scientists realize fully the assumptions they are making, willing or not, when pooling into a same histogram data coming from different locations and considering such histogram as an estimate of a probabilistic distribution. First they need the hypothesis of stationarity in space; second the presence of spatial auto-correlations implies that data be unequally weighted according to their relative locations and the degree of spatial continuity of the underlying phenomenon. The novel technique of indicator kriging allows construction of local or global histogram which can be considered as unbiased estimators of precisely defined probabilistic distributions, full account being given to the underlying continuity. Such estimates of local distributions can be used in mine planning for estimation of local recoverable reserves.

Jan 1, 1982

By J. A. Muñoz, A. Ballester, C. Gómez, M. E. Sevillano, M. Figueroa

The electrochemical behavior of massive chalcopyrite (CuFeS2) electrodes has been studied in the absence and-in the presence of mesophilic microorganisms, using cyclic voltametry as analytical technique. The culture was principally formed for Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans. The results showed that the reactivity of the chalcopyrite gradually increased with the bacterial treatment. The anodic dissolution process of the chalcopyrite treated with microorganisms was related to the breaking of passive layers when the applied potential increased. The analysis of the surface products showed that the chalcopyrite was covered with a superficial film avoided its dissolution during the bioleaching test. So, the rest potential of the bioleached samples increased possibly as consequence of its superficial transformation.

Jan 1, 1995

By JIAQI JIN, Chen-Luh Lin, Amanda N. Erskine, Jan D. Miller, Shijie Wang

The liberation and exposure of valuable mineral grains in ore particles are of significant importance in understanding the efficiency of flotation separations. A flotation feed sample from the Kensington concentrator was scanned by micro Xray computed tomography (micro-XCT), to determine the liberation and exposure of auriferous pyrite grains. The analysis results suggest a satisfying extent of liberation for particle sizes smaller than 212 μm. Theoretical flotation recovery of pyrite for selected particle size fractions was predicted from the three-dimensional liberation and exposure analysis. The plant flotation tail was also characterized by micro-XCT to identify liberated and partially liberated pyrite particles that might not be collected into the concentrate. However, liberation analysis of the tail sample revealed that the majority of liberated pyrite was recovered in the plant flotation circuit. Trainable Weka, a machine learning segmentation approach, was compared with the Watershed thresholding segmentation for the 106 × 45 μm particle size fraction scanned at a voxel size of 1.85 μm. Improved segmentation of small particles was found using the machine learning method.

Mar 1, 2024

By Russell G. Slayback

Feasibility investigations for prospective gold mines too often neglect to consider ground water. Simple observations and tests during drilling exploration can provide useful data on probable water conditions. As the prospect becomes more serious, more detailed investigation of ground water and dewatering needs may be warranted. Ignoring ground-water conditions can lead to costly mistakes.

Jan 1, 1987

By K. Hansson, A. Jedborn

Background In the mining industry, conversion of fine particles into a slurry is often part of the normal processing of the ore. Therefore, from a system's point of view, slurry transporta¬tion would be considered as a natural alternative, all the way from the working face to the final processing. In underground mines, there is sometimes a considerable inflow of ground water that has to be pumped out. When the mine dewatering installations are integrated with a hydraulic hoisting system, the cost of power needed to pump out the ground water can be excluded from the cost of hoisting, compared with other modes of transporting the solids to the surface. The chief advantage of hydraulic hoisting is that the hoisting capacity can be increased at comparatively low total cost without necessitating the sinking of new shafts. Alterna¬tive examples include deepening of the existing mechanical hoisting system, truck, or conveyor belts transport in ramps to the present level. These often become very expensive. The economic effectiveness of hydraulic hoisting and hydraulic design considerations have been discussed by Kostuik (1965) and Sellgren (1985, 1986) for both small shallow mines and large deep underground mines. Objective and scope The objective of this study was to demonstrate the feasi¬biliy of hydraulic hoisting in hypothetical examples of mine deepening. Underground grinding to a maximum particle size of about 700 um (about 25 mesh) is considered. The pumping of ground ore products with positive displacement plunger or membrane type of pumps at working pressures of up to 15 MPa (2200 psi) is a thoroughly tested technique (Venton, 1986). Hydraulic hoisting system A hydraulic hoisting system is described schematically in Fig. l . The ore is mined, handled, and crushed conventionally. It is then ground wet underground. The slurry is then tempo¬rarily stored in an agitated tank and pumped to an agitated receiving tank on the surface. The ore is then further processed in the concentrator. The capacity of a pipeline is very high. For example, an annual production of 500 Kt (550,000 st) of ore can be handled in a 100-mm-diam (4-in.-diam) pipeline. Systems layout - economic effectiveness Schematic mine layouts are presented that represent situ¬ations where hydraulic hoisting often is the most economical alternative. A situation where the ore is trucked to the level of the existing hoisting system is shown in Fig. 2 (following page). With hydraulic hoisting, only a shaft for ventilation, pipe¬line, and personnel are needed. In a first phase (Fig. 2), a hydraulic hoisting installation with crushing and grinding units, storage facilities, and pumps has been located at a level of about 400 to 600 m (1310 to 1970 ft) below the surface. With further development of the mine, the hydraulic hoisting

Jan 1, 1989