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By G. Newman, C. D. Sellars, E. A. Portfors

Power for mine operation in remote locations is usually provided by diesel generators. For gold mines where processing is normally desirable on-site, power requirements can be significant and the operating cost for diesel generation then becomes an important factor in mine feasibility. If a suitable site is available, a small hydroelectric power facility near the minesite can provide a significant portion of the mine power requirements. The hydrological, engineering and economic factors involved in small hydroelectric power development are described in this paper. Capital costs are minimized by run-of-river hydro development which does not require a dam and reservoir and has less environmental impact. During periods of low flow, diesel generators are used to make up the power demand. The hydrologic analysis required to determine unit energy costs is described and technical requirements for linking the hydroelectric power facility with diesel generation are outlined. Case studies are presented demonstrating the economic advantages of a small hydro installation. One case study is for a proposed gold mine in British Columbia and the second is a large operating gold mine overseas, for which the hydroelectric power scheme is presently under construction .

Jan 1, 1987

By Kelly Sands

"Mitigation may be considered a hurdle when it comes to environmental permitting. For complex projects with site specific mitigation plans, the time to devise those plans and get them approved can be a long and costly endeavor. However, mitigation options are expanding and the mitigation banking industry has grown tremendously over the last two decades, helping projects move forward with less debate. Mining companies are recognizing the value that mitigation banks provide in helping to shore up project timelines and costs. Where possible, companies are taking advantage of the opportunities to buy credits from thirdparty providers offering mitigation bank credits. In some instances, mining companies are taking matters into their own hands by establishing mitigation banks to realize their own mitigation freedom. That can have its advantages and disadvantages, as discussed below. All in all, the expansion of mitigation options has streamlined the permitting process, introduced flexibility, improved project permitting timelines and loosened the permitting girdle.Compensatory mitigationCompensatory mitigation involves actions taken to offset unavoidable adverse impacts to wetlands, streams and other aquatic resources and authorized by Clean Water Act section 404 permits and other permits. As such, compensatory mitigation is a critical tool in helping the federal government meet the longstanding national goal of ‘‘no net loss’’ of Waters of the U.S., both in acreage and function.Section 314 of the National Defense Authorization Act for Fiscal Year 2004 required the Secretary of the Army, acting through the Chief of Engineers, to issue regulations “establishing performance standards and criteria for the use, consistent with Section 404 of the Clean Water Act, of on-site, offsite, and in-lieu fee mitigation and mitigation banking.” The provision also required that those regulations ‘‘maximize available credits and opportunities for mitigation, provide flexibility for regional variations in wetland conditions, functions and values, and apply equivalent standards and criteria to each type of compensatory mitigation’’ (73 FR 19595). The result was the Final Rule on Compensatory Mitigation for Losses of Aquatic Resources issued in 2008 (33 CFR Parts 325 and 332).”"

Jan 6, 2017

By N. C. Saxena, S. K. Puri, A. K. Pal

The condition-based monitoring system is an important innovation for reducing the downtime of costly, heavy earth- moving machinery (HEMM). Vibration severity measurements were made on the HEMM located at the Gevra Project, the largest coal opencast project in India. Whenever the vibration severity levels exceeded the permissible limits, necessary actions were taken to replace the defective parts of the ma- chine. The systematic vibration monitoring of 120-t (132-st) dumpers, followed by corrective measures led to a substantial increase in component life (8.18% for an 445E Dressor and 28.44% for an MK-30 Unit Rig). The associated costs (including spareparts) were reduced by 21.55% and 25.74%, respectively. Because of the reduced downtime, savings for these two dumpers over the period from March 26 to June 25,1998, were of the order of Rs.26.47 (US$0.649) million.

Jan 1, 2000

By H. Burton

"The selection of the ultimate pit shell has a major impact on the overall value of a mining project. The size and shape of this pit drives the selection of pushbacks, equipment, and project strategy, each of which are significant in their own right. Optimization of the ultimate pit shape is typically done using the Lerchs-Grossman algorithm with inputs of production costs, commodity prices, and pit slope constraints. This method ensures that every tonne mined is profitable but does not take into consideration the timing of material release. This timing is essential when calculating the Net Present Value (NPV) of the project, which is one of the most popular metrics for valuing deposits. Often, when the mining schedule and discounting are applied, material that was considered profitable before discounting becomes sterilized. The objective of this paper is to show the methodology for improving ultimate pit selection by considering the production schedule. Application of this technique will generally produce a smaller and higher-value pit than using the Lerchs-Grossman algorithm alone. INTRODUCTION The Lerchs-Grossman Algorithm was developed in the 1960s and exists to produce a mathematically optimum shape for open pit mines (1). This algorithm is now an industry leading technique for producing the theoretical optimum shape for open pits and is used in many popular pit optimization and strategic planning software packages, such as GEOVIA’s Whittle. The Lerchs-Grossman (LG) Algorithm is based on graph theory and optimizes on the assumption of non-discounted cash flows. This produces a mathematically optimum shape, but does not consider the timing with which the material will be removed from the ground. This is an important consideration, given that one of the most popular metrics for evaluating mining projects is Net Present Value (NPV) (2), which relies on the timing of cash flows as a major differentiator between options. This paper will discuss issues inherent in the use of ultimate pit selection based on undiscounted economic factors and illustrate a simple technique in Whittle, a leading software package, which can be used to improve the NPV of projects."

Jan 1, 2015

By John W. Stevenson, Ted L. Sartain

Underground booster fan installations are currently employed in hundreds of coal mines throughout the world. Such installations, when properly designed and maintained, have proven to be safe and effective tools to provide desirable airflow volumes on sections or in areas of mines where the ventilation requirements exceed the capacity of the main fan system. In cases where an airshaft cannot be justified due to surface topography, depth of cover, or limited reserves a booster fan can serve the same purpose, be operational in a fraction of the time and at a substantially reduced cost. Booster fans are currently non-existent in U.S. coal mines. This is primarily due to lack of acceptance by the Mine Safety and Health Administration (MSHA), which has failed to acknowledge the merits of a booster fan system. Also, the absence of booster fan provisions in Part 75 of the federal regulations has led to the misconception that booster fans are legally prohibited in U.S. coal mines. In 1986, Jim Walter Resources, Inc. (JWR) developed and submitted to MSHA a plan to install and operate an underground booster fan at the No. 7 Mine. Detailed computer simulations were used to substantiate JWR1s position, that the booster fan could effectively provide the needed airflow on a developing section without adversely affecting ventilation in other areas of the mine. JWR also realized that numerous safeguards and operating procedures were essential for providing a safe system. Thus, safety features such as electrical interlocking, independent power supply, remote atmospheric monitoring, etc., were incorporated into the plan. This paper is a case-study that discusses JWR's proposed plan to install and operate an underground booster fan at No. 7 Mine. Unfortunately, MSHA's continued negative response has prevented implementation of the plan.

Jan 1, 1989

By Paul Mitchell, Clive Potter, Miles Watkins

Meldon Quarry is a seemingly rare occurrence of acid rock drainage (ARD) in a quarrying operation.4 With surface waters discharging to a tributary of a salmon-bearing river, it is subject to stringent discharge conditions. The quarry predates effective environmental management, and preventative, control and treatment measures were not implemented until relatively recently. However, retrospectively implementing standard preventative approaches at the site is costly, technically difficult and of uncertain benefit. This paper overviews the recent site history and introduces data from a demonstration by KEECO (UK) Limited of its Silica Micro Encapsulation (SME) water treatment technology.

Jan 1, 2000

By Ian Sheppard, Kugan Kuganathan

The Mount Isa Rocky Paste Fill (RPF) was one of the five fill options investigated for the Enterprise Mine filling between June 1996 and September 1996. Co-disposal of deslimed cemented tailings (CHF) and suitably graded rockfill (RF) in certain ratios produced the rocky paste fill. The RPF behaved like a cohesive paste with very high proportion of rockfill in the mix. Several large-scale mixing trials and drop tests proved that the rocky pastefill results in a homogeneous fill mass after placement. Segregation of RF was a common problem with MIM's traditional cemented rock fill (CRF), which is a combination of CHF and RF. The segregation was eliminated and a non-segregating paste like fill was created by optimising the particle size distribution of RF, and combining the RF and the CHF in optimum ratios. In rocky pastefill, the excess water in the cemented deslimed tailings slurry is taken up by the rockfill as the surface moisture on the rockfill particles and also as pore water between the particles. This results in thickening of the CHF, and the resultant mix is a non-segregating cohesive paste, which can easily spread to any horizontal distance inside a stope at a very low surface angle. The rocky pastefill releases no free water and relatively more pervious than the standard CHF due to rockfill component. With an average cement addition of 1.5 to 2% the rocky pastefill can develop higher strengths over 1Mpa. The rocky paste fill is applicable in many situations and can accommodate a variety of coarser materials that would be available in different mine sites. This paper present the research work and the experience associated with the rocky paste fill, and gives clear design principles for any potential users.

Jan 1, 2001

By Charles W. Bauer

Most of the aluminum produced in the United States today is derived from foreign bauxite deposits. Earth Sciences, Inc. initiated a program to evaluate domestic non-bauxite sources for alumina in the 1960's. In the initial evaluation of alunite, domestic resources were not sufficient to support development. An exploration program led to the discovery of large deposits of alunite in Utah and several other western states. Identification of alunite is difficult as both its physical and chemical characteristics are similar to the minerals with which it is associated. Most of the significant alunite deposits in the western United States are replacement type deposits. These deposits have formed as a result of hydrothermal alteration of volcanic, sub-volcanic, and igneous rocks. Typical alunite deposits contain between 30% and 50% alunite between 50% and 70% quartz with minor amounts of other minerals. Four mineralogical zones are common in these systems. They include a siliceous zone, a quartz-alunite zone, a kaolinite zone and a chlorite-montmorillonite zone. Total U.S. reserves of alunite were estimated at 20 million metric tons (at 30% alunite) by the U.S. Bureau of Mines in 1941. Here recent work by the U.S. Geological Survey estimates reserves of 252 million metric tons and potential resources at 1.4 billion metric tons. Reserves and resources estimated for 23 properties on which field work has been done by ESI are considerably higher. Most of these properties have reserves and potential resources of several hundred million metric tons. The combined demonstrated reserves at these properties are estimated to be about 650 million metric tons. Inferred reserves are estimated at 2.5 billion metric tons and potential resources at 8 billion metric tons. It appears that the U.S. has sufficient reserves and resources for alunite to be considered as a potential non-bauxite source of alumina.

Jan 1, 1980

By G. J. S. Govett

Dwindling near-surface mineral reserves emphasize the need for the development of exploration techniques capable of greater depth penetration; geochemical techniques tradition- ally have been restricted to the search for deposits having at least a sub-outcrop expression. Rock geochemical techniques developed in Cyprus in 1967-1968 recognized anomalous conditions in volcanic rocks up to one mile from an ore de- posit. Research by the Exploration Geochemistry Group at the University of New Brunswick has shown that some massive sulphide deposits in New Brunswick have well-defined halos of major, minor, and trace elements in the host rocks extending up to 1,200 metres (4,000 feet) laterally along the same stratigraphic horizon, and up to 450 metres (1,500 feet) vertically in hanging wall rocks which apparently post-date mineralization; well-defined halos have also been found in foot- wall rocks. Some of these halos are readily identified as individual elements or as element pairs; others are so subtle as to be recognizable only through computer-calculated multivariate analysis. Research continues to extend the dimension of rock geochemical halos for regional exploration and for identification of more restrictive anomalous conditions which may closely define the location and extent of buried sulphide deposits.

Jan 1, 1975

By Muhammad I. Kabir

A new minitest of in situ uranium leaching processes at reservoir conditions is proposed. The test which consists of a single observation/ production well and two observation wells is designed to permit the evaluation of both restoration and leaching parameters. It is shown that by using a straight forward history matching procedure, sometimes called a type curve analysis, both the rate of leaching and the ultimate uranium recovery can be evaluated based on the results of the test. Type curves are presented for the case in which the reaction rate is kinetically controlled and there are no other minerals competing for oxidant. Other situations can be approached using the same techniques as those presented here.

Jan 1, 1981

By L. E. Bowman

Efficient filtration of fine kaolin particles plays a crucial role in processing of raw kaolin to a marketable product. Oftentimes, filtration Is the rate controlling step of the whole process. As a consequence, plant production is dependent, to a great extent, on the rates being achieved In filtration. In order to alleviate the bottleneck in production, Nalco Chemical Company initiated a reagent development program to chemically enhance the performance of the filtration units. Filler aids of different classes were synthesized for evaluation. These include reagents whose primary mode of functionality were: coagulation, flocculation, thickening, and combinations of the preceding. All reagents that were synthesized and tested were listed under the appropriate Food and Drug Administration sections of the Code of Federal Regulations. This paper discusses the development and application of a new reagent that Improves the filter production rate with minimal Impact on filter solids. The results of laboratory filter studies along with plant data are presented and discussed. Plant data indicate that this reagent is capable of increasing production rates by as much as 35% on various clays of coarse particles to the finest fractions, as well as clays that are calcined. The reagent's Impact on solids content, re-slurrying characteristics, Brookfield and Hercules viscosity, and drying is within the standards set by plants who have evaluated and now use this product.

Jan 1, 1993

By Theodore H. Budd, Douglas J. Heinz

This report concerns the successful construction of Contract No. 287 of the Northeast Side Relief Sewer System for the Metropolitan Sewerage District of the County of Milwaukee. The contract involved the construction of approximately 3316 meters (10,880 feet) of tunnel concrete lined to 1.83 meters (72 inch) internal diameter; 30.48 meters (100 feet) of 1.83 meters (72 inch) reinforced concrete pipe jacked-in-place; a river crossing of approximately 107 meters (350 feet); 197 meters (647 feet) of 1.83 meters (72 inch) reinforced concrete pipe in open-cut; several diversion and flow monitoring structures; and miscellaneous manholes and appurtenances. The contract proposal, which was extremely prescriptive, did allow alternative methods of primary support consisting of precast reinforced concrete segments, steel liner plates, steel ribs with wood lagging, and combinations thereof in designated areas. The specifications required the contractor to designate which support scheme it intended to use. The specifications also required compressed air as a means of ground water control for approximately 2316 meters (7600 feet) of tunnel. The alternative selected in the bid proposal was the support method consisting of steel ribs and wood lagging for 2263 meters (7425 feet) of tunnel and steel liner plates for the remaining section. Shaft supports, by specification, were designed to be steel liner plate with steel ribs varying in size from 4.27 meters to 6.10 meters (14 foot O.D. to 20 foot O.D. ).

Jan 1, 1983

By Frank E. McCall, John K. Marshal, Fred Garcia

Since the advent of longwall mining systems in the United States, mine operators are increasingly relying on methane drainage techniques to supplement the ventilation system. The most commonly used technique is the vertical gob borehole. The number and spacing of vertical gob boreholes per panel is generally based on experience and underground conditions. To design a more efficient methane drainage systems, mine operators must accurately determine methane gas produced. Thus, mine operators must monitor gas flow and methane gas concentration on every vertical gob borehole on active panels at least once or twice during each 8-hr shift. As the mine grows, it is possible to have more than one operating longwall and many vertical gob boreholes. Thus, daily visits to each vertical gob borehole site can become very time consuming. During weekends when methane gas concentrations typically drop because there is no mining activity, borehole sites may not be visited. To obtain accurate gas flow data, a gob borehole monitoring system was designed and constructed by the U.S. Bureau of Mines (USBM). Gas flow, methane gas concentration, gas temperature, barometric pressure, and vacuum pressure of the exhaust fan are the parameters collected by the system. The system also includes circuitry for automatic shutdown of the exhaust fan and an alarm system before an unsafe condition is created. Telemetry components were also integrated into the system to allow for transmission of borehole data to the mine office. As a test, the system was installed and operated on a vertical gob borehole for six months. Test results indicated that intermittent measurements with hand-held instruments from vertical gob boreholes were always higher than gas flows measurements made by the gob gas analyzer system. This paper describes the system components, operational characteristics, and the results of the test program.

Jan 1, 1995

By J. R. Hoskins

Method - A direct approach to instrument users, initially by letter and later by telephone or personal contact was made. The resultant data was compiled to give specific use information on the seven instruments. During the course of the study attempts to evaluate the Griswold Gage were abandoned when it became apparent that the gage was not being commercially produced. One company is developing the gage for its own use. The information presented is the result of over 1200 inquiries.

Jan 1, 1973

By John Frostiak, Don Welch, David Landriault

The use of paste technology for underground cemented backfill is widely accepted in the mining industry today as a potentially cost effective alternative to cemented rock and hydraulic slurry fill. While paste backfill is not the appropriate backfilling method for all mines, there are presently 23 operating tailings paste backfill plants throughout the world. This new technology has gained increasing acceptance as a backfill method over the last decade and its use is now expanding into the surface disposal of tailings using the stacked, thickened tailings disposal concept. Over the next 18 months there will be ten new paste plants commissioned in the world. Five of these ten plants will be used exclusively for surface tailings disposal or a combination of surface disposal and underground backfill production. The thickened tailings disposal concept, developed by Dr. Eli Robinsky in the early 1970's, has been in use for decades at several mine sites throughout the world (Kidd Creek Mine site in Northern Ontario), but always utilizing non segregating high density tailings slurry central discharge, stacked tailings placement. With the use of a higher solids content paste, the typical 2-degree beach angle can be increased to ten degrees or more with no runoff water and minimal shrinkage crack development through desiccation. This paper presents the design of the first mine to implement true surface paste disposal, Barrick Gold Corp's Bulyanhulu Mine in Tanzania. The paste system will be commissioned in the first quarter of 2001 allowing performance data to be collected to define the full potential of paste technology for surface tailings disposal.

Jan 1, 2001

By P. A. Tuzinski, L. J. Dahl, N. R. Adamson, S. E. Brink, R. L. Blake

The US Department of the Interior, Bureau of Mines is developing a process to selectively extract manganese from oxide ores as part of its in situ mining research program. The Bureau is conducting site characterization studies of two manganiferous iron-formation deposits. These studies include: drill core, regional stratigraphic relationships from the existing geologic database, ore body geometry, geologic structure, hydrologic conditions, accessibility of ore minerals to leach fluid, surface subsidence potential and data collected from laboratory leaching experiments. This information is being used to evaluate the technical, environmental and economic feasibility of in situ mining of manganese for these two deposits. This paper will focus on the stratigraphy, mineralogy, ore textures, fractures, permeability and porosity as they relate to in situ mining.

Jan 1, 1994

By Robin J. Hickson

The Ortiz Mine is operated by Gold Fields Mining Corporation, a subsidiary of Consolidated Gold Fields Ltd., one of the world's major gold producers. The Ortiz Mine is Gold Fields only heap leaching facility as well as being their first operating mine in the U.S.A. The hydrometallurgical processes utilized for recovery of gold and silver at Ortiz are discussed along with the several practical changes in operation adopted since start-up. Included are heap leaching by cyanidation, concentration of values on activated carbon, desorption, and the final electrowinning steps prior to shipment. Construction costs and pertinent technical data are shown.

Jan 1, 1981

By Günter Strappler, Max John

When tunneling through karstic terrain, diverse and complex karst structures are to be expected. By means of drilling ahead of the face using drill jumbos, these structures can be detected to such a degree that by applying proper support measures both open karst cavities and karst holes surrounded by boulders embedded in soft rock can be mastered without causing any break-outs. Support measures such as spiles ahead of excavation, sealing off cavities, back?lling with sand, etc. have to be planned schematically and adapted to the dimensions and formations of the karst structures on site. An essential requirement for a smooth excavation procedure is the availablility of all necessary tunneling equipment for excavation by drill and blast as well as for excavation of soil, with experienced tunnel engineers being in charge of any adaptions on site.

Jan 1, 2003

By Duk-Won Park

Since geologic anomalies are one of the governing factors of instability of underground openings, it is extremely important to know in advance the locations and extent of these anomalies such as faults and weak zones. At an underground coal mine in the Black Warrior Basin, core drilling was conducted to find a fault in an area where they were planning to locate longwall panels and possibly a shaft. Core logging did not provide sufficient information to delineate the exact location, strike, and dip of the fault. However, a high resolution reflection seismic study successfully solved this problem. This experience proved the seismic exploration technique could be used for premining coal exploration by reducing drilling costs and providing more accurate and detailed information about geologic anomalies.

Jan 1, 1988

By W. W. Atkinson

This paper describes some concepts developed in a geologic data recording system at the Victoria, Nevada breccia pipe-skarn copper mine. The recording system is not fundamentally new, but represents expansion of earlier ideas. The paper is based on the philosophy that a high quality geologic data base is necessary and that it should be complete, clear, standardized, neat, quantitative, and readily useable. It may be multi-colored or simply black and white. Graphic, descriptive and quantitative recording of data is essential. A format for core logging is presented and discussed and as well as a multiple overlay system for recording data gathered in surface mapping.

Jan 1, 1983