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By Stewart R. Wallace

In the spring of 1959 while visiting the offices of the US Geological Survey (USGS) in the Denver Federal Center, I had a chance encounter with Paul Theobold, a former but, at that time, casual associate. Paul mentioned to me the results of his work on stream sediment geochemistry (Theobold and Thompson, 1959). Using panned concentrates, Theobold and Thompson had discovered a tungsten anomaly in Clear Creek and followed it upstream to its source on Woods Creek, a small tributary to the West Fork of Clear Creek. The specific source was a debris cone about 0.8 km (0.5 mile) upstream from the mine yard at the Urad molybdenite deposit. Because of the genetic and zonal association of tungsten and molybdenum at Climax, I found this very interesting. Accordingly, I related this information to Robert Henderson, general manager of western operations for Climax, and asked his permission to do some follow-up work. He, in turn, telephoned Frank Coolbaugh, the president of Amax, telling him of my interest and saying that, "Climax would take care of it." On my first visit to Urad, my companions (Dave Jonson, Bruce MacKenzie, and Dick Baker) and I were confronted by a "Cousin Jack" caretaker who made up for his diminutive stature by a "pistolover" that hung down almost to his knee and by a watchdog that was one-half wolf and one-half mean sled dog. We retreated discretely to Clear Creek and then climbed up the "back" side of Red Mountain by separate routes, across the ridge crest, and part of the way down the "front" side, sampling as we went. Although much of the ground was covered with snow, we found lots of puzzling but friendly looking rocks and the geochemical results were interesting. A geologic map of central Colorado showing the location of the Urad-Henderson and Climax deposits is shown in Fig. I.

Jan 1, 1991

By G. Fehr, B. B. Panda, R. Bansberg, K. Arnold, T. Freiman

To evaluate the potential for process solutions to contaminate groundwater outside of the area of the Oxide Pit, it is necessary to predict the ultimate maximum pit lake elevation once pit-related mining activities have ceased. A water balance model was developed based on the existing pit geometry, the groundwater flow equation, and assumed hydrologic input parameters. The model assumed that at any point in time, total inflow into the system (i.e., direct precipitation, surface water and groundwater) minus outflow from the system (evaporation from the lake surface) was equal to the change in the pit water volume. The pit lake depth over time was predicted by assuming a succession of steady- state water balance conditions over short time increments. An analytical method using a spreadsheet and computer model was employed in this study to model the filling of the lake in the Oxide Pit. A sensitivity analysis was performed to evaluate uncertainty associated with the input parameters in the model. The sensitivity analysis indicated that the model was most sensitive to values of precipitation and evaporation and to the static water table.

Jan 1, 2003

By L. A. Puchkov

Problems of how to use artificial intelligence (AI) methods and expert systems (ES) to control complex industrial projects have lately become significant in practical terms. Mining ventilation systems undoubtedly belong to complex multi dimensional objects of control with stochastic nonstationary and nonlinear processes. Formal models based on automated ventilation control, do require awkward algorithmic solutions, moreover, a number of tasks become the operator's headache, and the quality of their solution depends on his experience and intuition. These tasks include: - identifying pre-accidental situations and determining their causes; - making well-grounded decisions with regard to changing ventilation regimes, forecast of mining operations taken account of; - controlling ventilation systems in emergency situations, e.g. when in accident, etc. It is in this context that we have for a number of years been investigating how to practically use AI methods for operative control in dynamic aero-and-gas mining processes, one of our research directions being devoted to working out a consulting programme for the ventilation system operator. Our researching and modeling problem was identification of aero-and-gas situation in different parts of ventilation network and its interpretation in order to determine possible causes for gas regime changing and unexpected consequences. We would single out the following stages in this task: I. Operative information procession coming to the data base from the sensors and analysis of hypothetical versions (using the associative rules base) with regard to factors which have caused significant parameter fluctuations (e.g. C%(t), H(t), Q(t) etc.)., 2. Selection of hypotheses in the knowledge base and forming conclusions in accordance with reliability scale. 3. Clarifying the obtained conclusions in dialogue with the operator. 4. Correcting the associative rules base.

Jan 1, 1992

By Ted H. Eyde

Specialty sand and bentonite are produced in the plateau province from the Bidahochi Formation near Sanders, Apache County, Arizona. It appears that deposits of both sand and bentonite formed during the Pliocene in fluvial and lacustrine environments, respectively, along the west side of the Defiance Uplift. The bentonite is an alteration product of airborne vitric ash that fell or was washed into lakes. In the Cheto district, the individual bentonite horizons, which range from less than a foot to more than 10 feet thick, are restricted to the position of the medial volcanic member. Bentonite production began at the Allentown mine in 1924 and the Chambers mine in 1926. In 1933 strip mining of the extensive deposits in the Cheto district commenced. Production increased each year to a peak of 270,000 tons in 1957. As a result of the introduction of synthetic zeolites into petroleum refining, production declined. About 40,000 tons of bentonite are currently produced from the district each year. Bentonite is shipped out of State for processing into desiccants, thickeners, and acid-activated clay products. The specialty sand was derived from Permian sandstones and deposited by streams draining the Defiance Uplift. Although stream channels are usually restricted to the upper member of the Bidahochi, stratigraphically above the bentonite horizon, a few actually cut through the bentonite. The well-sorted sand, suitable for use as a proppant in hydraulically fractured oil and gas wells, is localized in elongate lenses along the margins of the channels. These lenses range from 5 to 50 feet in thickness and often extend thousands of feet in both width and length. The sand is about 97 percent silica, has a yield of 40 percent in the minus 20 plus 40 mesh size fraction, and has a roundness of 0.6 to 0.7 on the Krumbein scale. Production of this sand began about 1961. All of the current production, which amounts to about 40,000 tons per year, is sold in the petroleum-producing area near Farmington, New Mexico.

Jan 1, 1987

By Carl D. Broadbent

The goal of slope mechanics is to achieve efficient and safe pit slopes. In the case of ultimate mine slopes the objective is to minimize the stripping ratio by steepening the slopes to their maximum stable limit. On the other hand, the inclination of working slopes is normally established by operating space requirements and the function of slope mechanics should be the continuous surveillance of slope conditions to assure long-term stability and to provide timely warning of impending slides so that corrective measures may be incorporated in production planning. In 1956 Kennecott instituted a program to provide the resources necessary to develop and maintain a slope mechanics capability, including technical knowledge, engineers, and instruments. Although the goal has not been fully achieved, very significant progress has been made. Other papers (3, 4, 7, 8, & 12) have described the purposes and detailed results of the most recent study carried out at the Kimbley Pit. The study has provided valuable experience and has given the industry a three dimensional picture of the stability variables that influence a mine slope. The study has better defined those areas which require further investigation and has indicated those design and analytical techniques which can be used with confidence. In effect, the study has paved the way for the next step; that of refining the design process and applying it for profit.

Jan 1, 1968

By G. O. Kesse

The Republic of Ghana, located on the West Coast of Africa, is one of the West African countries rich in bauxite deposits. The main occurrences of bauxite deposits are at Sefwi Bekwai in the Western Region, Aya-Nyinahin in the Ashanti Region, Atewa Range near Kibi and at Mount Ejuanema both in the Eastern Region of Ghana. These bauxite deposits belong to the so-called blanket deposits as they are associated with erosion surfaces of old peneplains and occur as cappings on the flat tops of hills or mountains whose heights are generally greater than 600 metres above sea level. These deposits can also be classified as laterite-silicate bauxites since they have been formed under tropical weathering conditions. Genetic and mineralogical investigations have revealed that all bauxite deposits of Ghana are the result of indirect bauxitization processes, for the minerals of the weathering parent rocks have not been transformed directly into gibbsite. In all cases, lithomarge of kaolinitic clay can be recognised. The geology of the major occurrences of bauxite in Ghana shows that the Mount Ejuanema deposit is the only deposit associated with the Voltaian System of rocks. This rock System consists mainly of sandstone, shale, mudstone, conglomerates and pebbly beds. All the otter deposits are associated with the Birimian System of rocks which are made up of metamorphosed lavas,pyroclastic rocks, hypabyssal basic intrusives, phyllites, schists, tuffs and greywackes.

Jan 1, 1984

By V. N. Kelly

The ability to link geological sections on a graphics screen to form three dimensional geology representation was implemented at Kidd Creek in 1987. This technique affords an opportunity to optimize metal estimation in ore at the Kidd Creek copper, zinc and silver mine, by applying enhanced interpretation methods. On a series of geological sections varieties of ore are outlined. These are linked from section to section to form polyhedra which closely simulate the three dimensional shapes of the different ore types referred to as mintypes. The orebodies are divided into zones, referred to as domains, that approximate the function of variograrns, for which' preferential continuity of mineralization has been estimated for distances in the width, strike and dip directions. These distances define ellipsoidal volumes of influence. The domains are also linked into polyhedra. Both types, coded by ore variety and zone, are mapped into the block model. Tonnage and metal values are calculated for ten-foot cubical cells of the block model by any of several estimation methods under domain control. In estimating the metal grades for a cell the predetermined search ellipse is applied to select only those drill hole assays of the same mintype as the cell designation. Once grade estimations have been determined for the cubical cells comprising the model, a wide range of stored information can be viewed. For example, in plan at any row elevation or on vertical section at any azimuth, as either printed values for the cells or as contoured data. This flexibility is of particular value in checking and refining the geological interpretation to better conform to ore types and grades actually mined. Combined with three dimensional geological modelling, and correctly chosen domains, the use of mintypes implants essential geological control into the system and prevents assays for one ore type from affecting grade estimation in adjacent ore types. The three dimensional geological modelling and block model segments provide information which is effectively applied to the stope design, production, planning and control parts of the system.

Jan 1, 1989

By R. L. McNearny, K. A. Barker

Four numerical models written with the "PFC2D " program were compared against four similar physical models. The numerical models were constrained numerically to closely follow the caving behavior of the physical models. Results from the numerical analyses closely simulated both the granular and blocky behaviors of the physical models, including bridging and interlocking of the simulated orebody during draw. The drawdown patterns and the rate of draw developed during numerical modeling also closely simulated the physical models. The same assumptions and governing parameters used in analyzing the first four models were applied to an additional model. The fifth model employed a completely different, uneven, draw sequence than the other four models, allowing the material to flow in a more granular manner with a demonstrated instability of the undercut sections between each drawpoint opening. Drawdown patterns and behavior of the numerical material of the first four models progressed at uneven and inconsistent rates, similar to those seen in the physical models. By inspection, the overall shape and flow lines of both the numerical and physical models were close in the area removed and in the flow characteristics. The fifth model proved to be the most unstable of all the models tested, with poor correlation to the physical models. The uneven draw sequence, coupled with an additional frictionless wall condition and an added drawpoint, caused the material to flow in a very granular manner. Information generated by this study can be used as a first approach in determining the proper draw rate, drawpoint spacing and undercut thickness for a block-caving operation. Numerical models are often difficult to predict and interpret. However, this study should increase the confidence level for use of the PFC2D program in the future.

Jan 1, 2000

By R. G. Graber

Field testing of GPS mining applications has confirmed the technical and operational viability of GPS for precise, centimeter-level positioning in harsh taconite environments. GPS hardware has provided consistent availability exceeding 90%, with precision in certain applications of ± 0.07 foot at 95% confidence levels. Despite these technical successes though, challenges persist in achieving effective GPS integration. These challenges include the acceptance of new job tasks by mine personnel, the capacity of typical mine data communications infrastructure and the need to design GPS interfaces for new mining equipment.

Jan 1, 1998

By J. Gallagher

Henderson Mine has been transporting molybdenum ore using a rail haulage system for the past 21 years. Due to the age of this system, limited performance, and obsolescence, a capital investment decision was imminent. Henderson used this opportunity to evaluate other transportation methods and continuously improve their mining practices. These efforts resulted in a new mine plan for Henderson, which ensures that Henderson will continue to supply high quality molybdenum into the 21st century. This paper will discuss the dramatic changes taking place at the Henderson Mine as a new production level is mined. These changes include the installation of an underground crushing, conveying, and truck haulage system, as well as increasing the scale of the panel caving process. Each of these topics will be discussed, as will their rock mechanics and material flow implications.

Jan 1, 1998

By G. M. Rao

It has been a universal observation that rich grades of ores and minerals are getting depleted, simultaneously the demands for civilization are ever increasing coupled with occurrence of poor grades of ores and minerals posing a problem to the processing engineers. At the same time, the cost of mining and milling are increasing, creating a situation where the management has to handle and process low grade ores at an economic level keeping environmental stipulations and control to be safeguarded which has been an additional cost for the management to comply with.

Jan 1, 1994

By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010

By M. L. Leming

The mechanisms of Alkali-Silica Reactivity (ASR) are briefly reviewed, test methods are examined, and typical specifications are discussed. In addition, views on responsibility of the aggregate supplier regarding specifications are presented.

Jan 1, 1995

By Jerzy F. Sobala

Large - scale tests at the Polish Safety in Mines Institute /established in 1925 as "Barbara" Experimental mine/ performed in underground and surface experimental galleries, simulating conditions in roadways in mines, are the basic source of knowledge about development and propagation of explosions. Investigations up to 1973 were performed under the Institute's former research director Professor W.B. Cybulski s supervision, whose handbook concerning combating of coal dust explosions in collieries has been also published in the U.S. (2), and are continued until now. For investigating explosions the "Barbara" Mine disposes of 170 m /7.5 sq m/, 200 m /5 sq m/ and 400 m /7.5 sq m/ underground gallieries as well as of 10 m, 25 m, 44 m and 100 m surface galleries. For example, in the 200 m gallery more than 5200, and in the 400 m gallery - more than 2200 test explosions have been performed. Basing on determination of explosion hazard in roadways in collieries and on data of scientific research performed at the Safety in Mines Institute, the strategy of combating the explosion hazard in mines was elaborated; it includes mainly diminishing of coal duet. deposition in roadways, and -because of the possible inefficiency of this safety means in some roadways in mechanized collieries -- the introduction of three additional defence lines against coal dust explosions. It should be mentioned that at the "Barbara" Mine the problem of coal dust explosion initiation was elaborated as contract work for the U.S. Bureau of Mines. The main aim of this paper is to discuss some aspects of methods and measures for combating coal dust explosion hazard in highly mechanized mines in the Polish mining industry where in some roadways explosible coal dust is present, but it is not the aim to evaluate the effectiveness of methods and measures for diminishing the make-up of coal dust and coal dust deposition rates in roadways.

Jan 1, 1980

By Steve Tadolini

Underground roof falls can have devastating effects on the safety of operations personnel, and equipment, and seriously impact production. Immediate steps are usually taken to danger off and secure the area while clean-up efforts are designed and implemented. A critical step, often overlooked due to production demand, is the determination of - why the roof fall occurred so that additional occurrences can be avoided in future developments or what measures can be taken to identify areas that have similar ?symptoms?? Forensic engineering includes the investigation of materials, products, structures or components that fail or do not operate/function as intended. The authors define forensics in ground control engineering as the study of evidence discovered while examining underground roof falls by applying expert observational techniques and established mining engineering principles to determine the probable cause, hypothesize solutions, and design engineering safeguards to prevent reoccurrences. Simply stated, the primary steps in the forensics of underground roof fall techniques are: ?Assess regional and local conditions prior to the event. ? Assess post-event conditions. ? Hypothesize plausible ways in which the pre-event conditions became the post-event conditions. ?Search for evidence that either denies or supports the various hypotheses. ?Apply engineering skill to relate the various facts and evidence into a cohesive scenario of how the event may have occurred. This paper details the proposed technique by utilizing a roof fall case study that required the examination of five primary factors: mine design parameters, excavation geology, method of excavation, method of support, and mining cycle times.

Jan 1, 2009

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black rock, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era and from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there .is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, go back thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages.

Jan 1, 1981

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 P. Croney

Environmental monitoring requires major effort and expense but management of data receives less attention. A modem database system can manage hydrochemistry, water levels, meteorology, geology and downhole geophysics data and is flexible to allow the storage of ad hoc data. Reports can be customized by the user and derived data generated from input values. The production of high quality maps with contours and hydrochemical diagrams is an essential part of the reporting process. These maps integrate directly with the current site survey information. These facilities are best provided by storing the data in an industry standard database such as Oracle or Access to which customized AutoCAD and Microsoft Office routines make direct SQL calls.

Jan 1, 1997

By K. R. McGinnis

A major cost to a mining company is funding of an exploration program. It is a necessary cost to insure the company's future. But if the exploration effort does not discover an economic are body, there is no return on investment and the days of the company are numbered. However, if you are aware of what exploration geologists are saying, it places the exploration process in a different light. Basically they are saying that ore bodies exist that contain 250,000 tons or less of gold and silver bearing ore that is cyanide amenable utilizing heap leach technology.

Jan 1, 1988

By N. I. Jayaraman

Dust scrubbers on continuous miners are steadily gaining in popularity. Recent Bureau of Mines research on scrubbers is reviewed, with emphasis on the following areas: * Development of a new type of water-powered scrubber which can be retrofitted to existing miners. * Comparison of scrubber effectiveness with blowing and exhaust line ventilation. * Improving the quartz dust collection of flooded-bed' panels.

Jan 1, 1989