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By G. G. O. O. Uwadiale, E. G. Okafor

A study was performed to characterize the Ishiagu lead-zinc deposit prior to beneficiation. The study included the use of XRD, SEM and both reflected- and transmitted-light microscopy. The results showed that the ore consists mainly of galena (PbS), sphalerite (ZnS) and quartz (chert), with pyrite, siderite and chalcopyrite occurring as trace minerals. The textural relationships among the minerals, their grain sizes and their locking characteristics, coupled with the chemical analysis of the ore, indicated that the galena and sphalerite can be separated by conventional beneficiation methods.

Jan 1, 1998

By Richard Kolada

If the emission of methane into any particular area of an underground coal mine remains constant, then the calculation of ventilation requirements is relatively simple. This is also true if the ventilation system is recirculatory. However, the emission of methane into a working area can vary considerably. There is always a risk that the ventilation will not be able to dilute the emission of methane to acceptable levels, because there are often short-lived peaks of emission which are very large. The ventilation design must therefore consider what is an acceptable level of risks and calculate the airflow requirements to meet this level. The acceptable level of risk can be calculated by examining the historical variation in methane emission into the area to be ventilated. For example, consider that an acceptable level occurs when methane emission peaks only exceed the capability of the ventilation one day in twenty. Then, from the history of methane emission, it is possible to calculate the necessary ventilation requirements. This method has been used since the early 1980s for conventionally ventilated districts. This paper examines the application of this technique to districts ventilated by recirculatory ventilation.

Jan 1, 1987

By Daniel W. Kappes

Until recently, the general expectation among mining compa­nies and financial analysts has been that the price of gold would remain on a generally upward slope. The recent drop in the price of gold has caused many people to re-think the issue. Of course, the price of gold is singularly difficult to predict, so it is difficult to tell which concept is correct. In the present financial situation, however, many junior gold companies are faced with the reality that money is hard to raise, and many senior gold companies find that they are facing a period of corporate losses even though they own solidly producing mines, As engineering consultants, Kappes, Cassiday has recently received several requests to review conventional milling projects to see if heap leaching is a more viable option. In regard to straight financial criteria such as return on investment and net present value, the question is usually fairly easy to answer. However, corporate decisions must often be based on less definable criteria. For instance, new stock issues tend to be more successful if they are larger, which tends to favor milling operations over heap leaches. The corporate issues are often subjective and difficult to generalize about, so I will con­centrate in this paper on a few financial concepts.

Jan 1, 1998

By Gastón Díiaz, Enzo Carranza Meza

El Teniente Mine of Codelco-Chile, located at Los Andes Range of Mountains, 90 kilometers South far from Santiago, the capital city, has been exploited for more than 90 years, with over 1000 million tonnes of copper ore extraction. No doubt, this particular record, has been possible to achieve due to an efficient combination of human and technological efforts in the exploitation of one of the biggest ore deposits of the world. Throughout times, the exploitation has evolved from a mainly manual one to a highly mechanized exploitation. Notwithstanding, different and several geomechanical problems that occurred in one of its areas, increased the risks to personnel that should normally operate large equipments in its working face. This last condition, forced El Teniente mine to design and develop systems and technologies that would allow the use of tele-operated LHD, picking hammers and drilling equipment (jumbos) from a safe zone. Currently, El Teniente Mine is using in its extractive works equipment such as LHD, picking hammers, and drilling Jumbos, that can be manually or teleoperated commanded from a Central Control Room located one kilometer away from the production area. In general, a new technological era has been opened in the mining exploitation at El Teniente: the exploitation era with telecommanded robots.

Jan 1, 1998

By Y. S. Roditis

A new method for interpolating a block model is proposed, where both the diamond drill holes (DHs) and blast holes (BHs) data are used. Combining these data types poses a geostatistical "class size" problem due to the different statistical properties of the densely populated BHs and the sparsely populated DH data. This paper discusses how linear regression was used to adjust the DH values prior to the interpolation to account for the "class size" problem which is inherent to the procedure. The correlation between the BHs and the DHs is found. The DHs are then corrected based on the regression line. Each block that falls within a certain range of influence of a blast hole is assigned a different code and is interpolated with the combined BH and regressed DH data set. Blocks that fall outside the range of blast hole influence are interpolated using the original DH data set. A comparison against other methods, indicate a 12% improvement over using DHs only and a 2% improvement over using BHs only.

Jan 1, 1992

By H. Maleki, G. Tetreault

This study was initiated by the US Bureau of Land Management (BLM) to develop guidelines for determining the maximum economic recovery of resources in coal mines. The work was in response to a requirement in the Mineral Leasing Act of 1920 and Federal regulations. The intent was to address the economic rainability of small, irregular reserves in existing longwall mines. In particular, there was a need to determine if room- and-pillar mining using a continuous miner (CM) was economically sound or whether unconventional (short or odd-shaped) longwalls could be used to recover small coal reserves economically. Small reserves, called "widgets " are left in longwall mines on one side of the mains near outcrops and adverse geological conditions or near any other location where reserve geometry does not lend itself to mining with a rectangular longwall panel. The work included the analysis of the geologic, geotechnical and economic factors that influence the recovery of small coal reserves; the analysis of historic changes in supply, demand and coal prices; the development of typical cost models for room-and-pillar and longwall mines; and the development of a practical methodology for determining maximum economic recovery. The methodology included an evaluation of the ratio of coal mined during longwall mining to that mined for development (LDR), as well as costs of maintaining coal quality depending on market conditions. The LDR is a good indicator of mine efficiency and overall coal recovery in modern longwall mines and, thus, is used to evaluate the increased costs associated with adding new development sections for extraction of small reserves. The study examines the economic feasibility of using unconventional longwalls for the recovery of medium-sized reserves, depending on site-specific geologic and geometric conditions.

Jan 1, 2002

By Russell J. Sheets

Reactivation of highwall slope failures during adverse weather had intermittently impacted haul road access into a previously mined open pit. These impacts ranged from limited access to full closures; however, the greater impact was to an underground mine that was developed within the open pit. Following several significant precipitation events, a rapid snow melts greatly accelerated movements finally closing the haul road and destabilizing other past failures. In addition to re-designing the overall pit access, the decision was made to relocate the primary portal to a more stable highwall. An accelerated surface geotechnical review was required to advance the portal relocation; however, only existing information from past investigation, existing geology model, visual inspections, and slope monitoring data were available for the assessment - no new investigations or data collection could be completed within the allowable timeframe. The evaluation included a review of the geology, an assessment of the current highwall condition and previously observed performance, and a rockfall analysis to evaluate existing catchment above the proposed new portal location.

Feb 1, 2024

By Lyle A. Hale

The subject area known as upper Dry Valley is located 15 miles due east of Soda Springs in Sections 14 and 23, Township 9 South, Range 44 East, Caribou County, Idaho. The railroad extending from Soda Springs to its terminus at El Paso's Maybe Canyon mine is 8z miles to the north in lower Dry Valley. Initial data derived from trench work in 1962 revealed a variety of econom¬ically significant alterations of the phosphatic beds related to the rather unique geomorphic development in the northern part of phosphate lease 1-012989. It was apparent that such conditions, while valid for near-surface beds in a strike direction, would be misleading if projected to the proposed depth limits of strip mining. Consequently, a subsurface mapping program was initiated in 1963 to determine: (1) the depth and horizontal extent of weathering and related phe¬nomena, (2) the depth, thickness, and quality of ore beds and intervening strata, and (3) structural geology as a guide for mining procedures. Successful use of a scintillometer in 1956 to detect the subcrop position of phosphate beds in the Smokey Canyon area of southeastern Idaho led to the conclusion that gamma radiation surveys of drill holes could be a useful aid in subsurface mapping. The objectives of this paper are: (1) briefly to describe geologic features characteristic of the phosphate lease area and (2) to demonstrate the practical application and theory behind gamma radiation logging as an effective tool in the economic evaluation of a phosphate lease.

Jan 1, 1969

By Renee Y. Allee

The Chino open pit mine, concentrator, and smelter are located in Grant county in Southwestern New Mexico. Chino Mines Company is a partnership, two- thirds owned and operated by Kennecott Santa Fe Corp., and one third owned by MC Minerals Corp. (Mitsubishi) of Japan. The concentrator, with a design capacity of 37,000 tons of copper-molybdenite ore per day, was commissioned in July, 1982. Further design modifications have resulted in an increase in throughput capacity to 42,000 tpd

Jan 1, 1986

By Leslie Thompson, Randy Hiebert, Marietta Canty

A paper is presented in which an innovative biological process is described for the treatment of cyanide-, metals-, and nitrate-contaminated mine process water. The technology is capable of detoxifying cyanide and nitrate and immobilizing metals in wastewater from agitation cyanide leaching as well as heap leaching. A pilot-scale demonstration is described in which a pilot plant was constructed to detoxify cyanide and immobilize several metals from a mine process wastestream at a mine in Nevada. The demonstration was performed jointly under the Mine Waste Technology Program (MWTP), which is funded by the U.S. Environmental Protection Agency (EPA) and is jointly administered by the U.S. Department of Energy's (DOE) Western Environmental Technology Office (WETO) and the Superfund Innovative Technology Evaluation (SITE) Demonstration Program under Interagency Agreement Number DW89938513-01-0. MSE Technology Applications, Inc. (MSE) located in Butte, Montana, was the contractor responsible for conducting the project, and Pintail Systems Inc. of Aurora, Colorado, was the technology provider. The pilot-scale unit was field tested at the Echo Bay McCoy/Cove Mine southwest of Battle Mountain, Nevada. The biotreatment process was con­sidered to be very successful in detoxifying cyanide from the mine process water. The process was also determined to be very effective in removing metals. The pH was consistently neutral­ized and nitrates were successfully removed in the mine process water. As a result of conducting these pilot-scale tests, the biotreatment process was concluded to offer an innovative, cost­effective alternative for the treatment of mining wastewaters.

Jan 1, 1998

By Elmer R. Drevdahl

During the last few years there has been a rapid increase in the development of the community or junior college throughout the United States, Some factors behind this development include the need for more college facilities to service the growing number of high school graduates, the desire of the public to provide some post high school education at reasonable costs, and the need to provide post high school educational opportunities not now provided by most of the universities and colleges. Many of the new community colleges provide at least three educational services including local opportunity to provide the first two years of a four year college program, two year technical-vocational programs of a terminal nature, and adult educational opportunities. The community college has the advantage of not being saddled with years of academic tradition which prevent it from changing to suit the educational needs of the community It serves. The flexibility of the community college in developing new programs, particularly in the technical areas, is going to provide industry with many of the badly needed technicians it is now unable to secure.

Jan 1, 1965

By Douglas H. Bolton

In recent years, equipment manufacturers have been busy developing remote control systems to catch up with the sophistication and efficiency of continuous miners. Now the tables are turned, and manufacturers are undertaking the new challenge of upgrading, refining and equipping continuous miners to take full advantage of the capabilities made possible by modern, successful remote control systems. Because the operator can safely advance the miner farther without pulling out for roof bolting, continuous miners now need to be equipped with means of complying with correct face ventilation, dust suppression, methane detection, diffusion and improved lighting. Some of the exciting possibilities being developed to catch up with remote control include feedback controls using laser beams as datum points, coal sensing devices with feedback signals to show the operator what the machine is doing, show where it is relative to the coal seam, how hard it is working, and more sophisticated use of cyclic control. Mining machinery manufacturers have accepted the new challenges, and faster, safer mining procedures are already in sight.

Jan 1, 1975

By P. C. Cochrane, I. S. Clelland, S. H. E. Phillips

Geological and hydrological conditions in the strata overlying the Salado Formation vary considerably in the Carlsbad, NM, area. The first four shafts sunk at International Minerals and Chemical Corp. (IMC) property have been located in competent and essentially dry conditions, while other shafts on adjacent properties have had such adverse conditions that ground freezing has been chosen as the water and ground control technique for shaft sinking. At the location of the IMC No. 5 shaft there has been extensive erosion and salt dissolution in the Rustler Formation, leading to collapse of some zones of the strata. Both ground freezing and pregrouting were considered as alternative methods of stabilizing the extremely poor ground conditions and controlling the potentially very heavy water inflows. It was decided that pregrouting the shaft was feasible and would offer substantial cost and time saving over a ground freezing technique. This paper describes the pregrouting techniques used and illustrates the requirement for flexibility in a grouting program so that it can be modified to reflect any new or additional information obtained during the progress of the grouting.

Jan 1, 1987

By D. E. Ranta, M. G. Schulz

Mining of Molybdenum at Questa, New Mexico has been accomplished by block cave methods since August, 1983. As caving progresses, a periodic geologic evaluation is made of the rock types present in finger raises on the Grizzly Level of the mine. The production maturity of the cave can be monitored by relating this data to geologic cross-sections through the orebody. The draw point mapping program is a simple and effective tool that is used in making draw control decisions at Questa.

Jan 1, 1992

By W. S. Urbanski, A. L. Devernoe, M. S. Walker

Theory and practice are described for a new processing method capable of precise mineral separations based primarily on differences in particle specific gravities at specific gravity split points from 1.5 to 21.0 and beyond. Separations are analogous to those achieved using rotating heavy media, except that the effective specific gravity of the fluid is created magnetically using a relatively dilute, low-viscosity, water-based magnetic fluid. Results reported here for a large, laboratory flow-through separator include: 1) 99% grade with 97% recovery in single pass separation of a suite of heavy minerals from quartz at I0 kg/h, 14 tph/rm2 of duct cross section, 2) 90% grade and recovery in single-pass separation of mixtures of sand-size, non-magnetic rutile (4.23 specific gravity) and zircon (4.72 specific gravity) at throughputs of 35 kg/h, 47 tph/rm2 of duct cross section, 3) partition curves having Ep90-10 transition widths 5% or less of mineral specific gravities, and 4) essential confirmation of the theory.

Jan 1, 1991

By Benjamin K. Pocock

When considering alternative equipment choices in mill or process flowsheets, it is important to determine both capital and operating costs of such equipment as well as other possible savings related to downstream operations. This paper presents a few case studies and shows cursory guidelines for the selection of equipment for new installations or in the retrofitting of existing plants. Based upon recent plant experience, suggestions are given to improve the operation of clarifiers, thickeners and vacuum filters.

Jan 1, 1986

By Palmer King

The increased emphasis on environmental protection, together with the exorbitant costs, or in many urban areas the complete unavailability of surface space, has resulted in a burgeoning demand for greater use of underground space. More and more, those considering new or expanded facilities are looking toward the possibility of utilizing underground space for communications installations, for transportation of people, industrial products, water, sewage and energy, and for industrial installations. Happily, this growing demand for use of underground space is accompanied by fast forward strides looking toward more efficient underground excavation techniques. The tunnel boring machine is already here and where ground conditions are suitable for its use it can greatly reduce the cost of underground excavations, savings of one-third or more often being realized. Research is underway involving excavation by use of laser beams, jetting, vibrations, improvement of tunnel boring machines to make possible the excavation of harder rock, and other advanced techniques. The Engineering Foundation estimated in 1973 that tunneling costs can be reduced as much as 30 percent by rapid excavation methods which are expected to be developed through ongoing research programs in the next few years. Your American Society of Civil Engineers reported in 1973 that $60 billion per year, or 15 percent of the gross national product, could be saved if facilities required to support life were located in the subsurface. Studies looking toward improved contracting practices are going on under the sponsorship of the National Academy of Sciences, and Mr. Al Mathews who is heading this program will address you during this session on the status of this project. I myself am a member of Mr. Mathews' study group and, considering the human element involved, it is too early to make predictions as to what can be accomplished in the way of savings in costs of

Jan 1, 1974

"?irovski Vrh" Uranium deposit in Slovenia is type of mineralized sediments in ore bearing belts of deflected S-structure, in which the belt is less than 25% mineralized. Ore bodies of irregular small thickness, unreliably contoured, made difficult estimation of correct contours, which are necessary for design and exploitation works. The deposit was explored by vertical boreholes made at the surface and by boreholes fanned from drives. For the purpose of application of this estimation method, 1 m composites have been made in slices which were parallel to the referential belt plane. Estimation was made for 1,5m x 1,5m x lm blocks which do correspond to the size of the containers in the ore transport stage. Two variables have been used: the first, indicator of function (ore=1, waste material =0) and kriging method; the second, logarithmical content of Uranium and Minimum Mean Square Error Estimation (MMSEE) method. Based on estimated values of those variables, probability of ore quantity as well as Uranium content over determined cut-off were calculated for each block. Those two parameters enable determination of the most probable form of the ore body in ecah one metter slice. Estimation of sixteen small blocks in a large 1,5m x 1,5m x 1m block made possible estimation of ore quantity and its content for the determined cut-off, as well as categorization of exploration. This method is being used for estimation of ore reserves and planning of exploration operations. The described' methodology was tested in an exploitation block.

Jan 1, 1986

By P. T. Brown

Denison Mines Limited, Canada's largest uranium producer located in Northern Ontario recently embarked upon an extensive development program that would allow them to substantially increase production and also meet the more stringent air quality standards established by the ministry of Natural Resources. To proceed with this program it was essential that the fresh air supply be greatly increased to the underground workings. A major portion of the mining area is located under Quirke Lake on the north limb of a syncline termed the Quirke Lake trough. The Denison engineers determined the most practical size and location for a proposed new fresh air shaft, eventually deciding to drive a 25 foot diameter shaft, 490 square feet in section for 1,800 feet long vertically. The shaft collar would be located on Roman Island, an island in Quirke Lake. A test hole was drilled from Roman Island to determine the ground through which the ventilation shaft would pass. This drill hole confirmed the location of the Quirke Lake over-thrust fault, a highly fractured water bearing zone 165 feet thick, approximately 800 feet below surface. Plans were made by Denison Mines Limited to seal and consolidate this ground when it was encountered by the shaft.

Jan 1, 1974

By R. W. Smith, A. Raichur, M. Misra, I. A. H. Schneider

The concept of microorganisms as chemical reagents (flocculants, flotation modifiers and flotation collectors) is quite new. Potential uses for microorganisms include their use in place of certain conventional flotation reagents and as flocculating agents in minerals engineering processes. In addition, in some studies micro-organisms have been used to modify mineral surfaces and, thus, the flotation or flocculation of the minerals.

Jan 1, 1995