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By John McMorran

An open pit mine design system should have the characteristics of being flexible, versatile, and simple. All of these characteristics are necessary for producing a dynamic mine design. In other words, a design that can be improved, updated, and implemented. Flexibility is an important characteristic due to changing times. For example, the effects of a changing economy, increased knowledge of the mineral deposit, or improvements in mining technology can result in a considerable, if not a complete change in the long range mining plans. Since the short range mining plans are based on the long range mining plans, they will-also be effected. Also, it is very important to validate the information used in the design or the design itself. This means the system should have the flexibility of being able, not only to detect, but to correct errors. Versatility is another important characteristic of a mine design system due to the wide range of situations that may appear. First, a design system must be able to handle both long and short term planning. This is necessary because of the variability in the definition of a time range. Second, a design system must be able to handle different types of deposits. Special emphasis must be placed on this issue, because many deposits, if not the majority, do not fit predefined categories such as bedded, massive, or roll-front, etc . . . Furthermore, the true test of the versatility of a design system is not only the ability to create an ultimate design but also to schedule sequences for this design. Thus, the versatility of being capable to design with a variety of time ranges, variety of deposit types, and scheduling are all important characteristics of the design system.

Jan 1, 1982

By W. H. Andrews

DEFINITION OF BAUXITE The term "bauxite" (1) dates back to 1821, when it was assigned to a deposit of red earthy material outcropping near the village of Les Baux in Southern France. Chemical analysis indicated the presence of aluminium oxide, iron oxide and water. Deposits of bauxite are widespread throughout the world although the major developments occur within 30 degrees of the Equator. Essentially bauxite is the product of weathering and leaching of a variety of sediments or rocks, generally in a high-rainfall tropical or sub-tropical climate, resulting in the enrichment of the aluminium oxide content. It is characterised by the presence of one or more of the minerals, gibbsite, boehmite, and diaspore. The other constituents are usually clay, (typically kaolin), hematite and/or goethite (iron-oxides), anatase (titanium oxide), and possibly silica as quartz. A variety of minor elements may be present, such as calcium, magnesium, phosphorus, vanadium, gallium, manganese, and many others in very small quantities. Organic compounds are normally present from development in association with a soil horizon where vegetation may be encouraged by the high rainfall necessary for bauxitisition. The physical form depends upon the geological history of the deposit and correlation also exists with the mineralogy. Older deposits which have been subject to burial are invariably hard and compact with the alumina predominantly occurring as boehmite or diaspore, while the more recent, surface deposits are frequently less compacted and gibbsite is the dominant alumina mineral. In these later deposits, the physical form can vary from the fine red soil (terra rosa) of Jamaica to the Weipa pisolites to the cemented Arkansas type. The presence of concretionary structures is an important aid in identification in the field.

Jan 1, 1984

By Bruce K. Cantrell, Stephen W. Stein, Kenneth L. Williams, David Hassel, Harvey Patashnick

In June 1992, the Mine Safety and Health Administration (MSHA) published the 'Report of the Coal Mine Respirable Dust Task Group; Review of the Program to Control Respirable Coal Mine Dust in the United States." As one of its recommendations, the report called for the accelerated development of two mine dust monitors: (1) a fixed-site monitor capable of providing continuous information on dust levels to the miner, mine operator, and to MSHA, if necessary, and (2) a personal sampling device capable of providing both a short-term personal exposure measurement as well as a full-shift measurement. In response to this recommendation, the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Center, initiated the development of a fixed-site machine-mounted continuous respirable dust monitor. The technology chosen for monitor development is the Rupprecht and Patashnick Co., Inc. tapered element oscillating microbalance. Laboratory and in- mine tests have indicated that, with modification, this sensor can meet the humidity and vibration requirements for underground coal mine use. NIOSH is continuing that effort by developing prototypes of a continuous dust monitor based on this technology. These prototypes are being evaluated in underground coal mines as they become available. This effort, conducted as a joint venture with MSHA, is nearing completion with every promise of success. The immediate benefit of this effort will be to researchers, regulatory personnel, and mine personnel, by permitting evaluation of specific mining practices to see which expose mine workers to excessive dust levels. Using this information, mine personnel can optimize mining procedures to reduce dust exposure. MSHA and the operators will also be able to use the dust concentration data to judge whether dust plan parameters are adequate to continuously maintaining environmental dust levels below the applicable standard. The second development recommended by the Dust Task Group was a person-wearable version of the continuous dust monitor. It will be a monitoring system designed to provide a measurement of worker exposure to respirable dust, both during and at the end of the shift.

Jan 1, 1997

By Neal I. Rosenberg

There is an old education maxim that a good teacher "first tells 'em what he's gonna tell 'em, then he tells 'em, and finally he tells 'em what he told 'em. I'm sure this says something about me as a teacher, and therefore as a student as well, but I'm going to begin by violating that maxim. The first thing I'm going to do is tell you what I'm not going to tell you. I'm not going to tell you that my company has found the solution to frozen coal problems. I'm not going to tell you that there is a miraculous new formula, and your frozen coal worries are over. Actually, it is really questionable whether there is a single step or process which will provide the answer. On the other hand, I do believe that at Union Electric we have made significant improvements in our ability to deal with frozen coal over the last couple of years, and I propose to describe some of the things we have done, what conclusions we have drawn so far, and the direction in which we are now headed. It would be well here to give a brief picture of the Union Electric system and the frozen coal problems we face. Union Electric is an investor owned electric utility with headquarters in St. Louis, Mo. Total generating capability is on the order of 6800 megawatts, which snakes us 24th or 25th largest in the United States. Power generation is by steam (both coal and oil fired), hydro, pumped hydro, and combustion turbine units. Although that is a diverse power supply, by far the largest source is our four coal fired steam plants. One receives coal exclusively by barge, the other three by rail. It is at these last three plants that the frozen coal difficulties arise.

Jan 1, 1980

By P. F. Ziemkiewicz, A. S. Knox

Large-scale use of CCBs in mine environments involves filling surface and underground coal mines with ash to address hydraulic problems, AMD, backfilling and subsidence. The environmental risk of land filling CCBs is generally evaluated by the Toxic Characteristics Leaching Procedure (TCLP) or the Synthetic Precipitation Leaching Procedure (SPLP). However, there is doubt regarding the applicability of these tests to long-term CCBs leaching behavior in groundwater associated with coal mines. The Mine Water Leaching Procedure (MWLP) was developed to provide a site specific risk assessment tool. The MWL Pprocedure is presented in this paper and compared with TCLP as a study.

Jan 1, 2003

By Bernard Scheiner

A number of wells were drilled at two phosphogypsum stacks, one at P-21 owned by IMC and the other at Agrico's South Pierce Stack. Each well was sampled, and composites representing 5-ft increments were leached with synthetic rainwater to determine the extent of metal and nonmetal migration. To simulate what was occurring in the stack, composite samples were placed in a column, so that the column represented the stack in miniature form. Leaching experiments showed that both metals and nonmetals moved down the column when water was added to the top of the column. Data obtained from P-21 showed that with time the concentration of metals and nonmetals reached equilibrium values. The concentration of Ca, SO4, F, Si, and PO4 were -600 ppm,~1,500 ppm, 32 ppm, 14 ppm, and 22 ppm, respectively. Column leaching of South Pierce material, representing 0 to 55 ft of stack, showed that after 355 in. of water, the stack was near equilibrium values down to the 33-ft level. With continued addition of water, the portion of the stack at equilibrium would continue to increase and eventually reach the values observed for P-21. The test showed that the sulfate concentration of the effluent from the stack would never reach the USEPA standard value of 250 ppm. During the leaching test, it was determined that the permeability of the phosphogypsum in the columns was 0.000103 cm/sec. This number was used in the modeling. The data obtained from the leaching experiments cast some doubt on the practice of entombment now being practiced for closure of phosphogypsum stacks. The data clearly shows that with time, the amount of material leaching from the stack is low in concentration, with only the calcium and sulfate at higher levels. When a stack is closed at an existing operating plant, allowing rainwater to fall on the stack and capturing the solution in the existing pond system would eliminate the need for covering the stack, since with time the closed stack would continue to leach and at some point reach the equilibrium values of the P-21 stack. Entombment means that the leachable material in the stack will always be there and will require monitoring forever. Allowing rainwater to decontaminate the stack may be the best environmental solution to the problem.

Jan 1, 1999

By G. M. Li

It is shown that seriously preoxidized arsenopyrite can adsorb a large amount of copper ions as unoxidized one, but without, release of corresponding amount of Fe ions; seriously preoxidized pyrite cannot adsorb copper ions, but with release of a large amount of Fe ions. However, if the minerals are rapidly oxidized with potassium permanganate solution, both arsenopyrite and especially pyrite can adsorb a large amount of copper ions, but still without release of corresponding amount, of Fe ions. Cu adsorption (if there is any) on both oxidized arsenopyrite and pyrite is not based on the Cu-Fe exchange mechanism.

Jan 1, 1991

By K. Takahashi

The methyl stretching vibrations for a series of normal and iso xanthates were determined using an infrared spectrophotometer, and the results were compared with the published information on the corresponding alcohols. The frequency shifts of methyl stretching vibrations may be attributed to the inductive effect of polar groups. The hydrogens in the shorter chain alkyl groups are somewhat polar and can be expected to interact with water molecules by hydrogen bonding. Contact angle, surface tension lowering, and solubility appear to be related to the induced polarity of the alkyl groups.

Jan 1, 1968

By Ben Benally, Joseph M. Hans

INTRODUCTION The decontamination of the former Shiprock uranium millsite and the interim stabilization of its tailings piles began in March 1974, and ended in June 1978. Personnel monitoring for whole body gamma ray exposure was conducted for selected individuals working at the mill site throughout most of this period. The millsite and exposure conditions are briefly described to develop a basis for interpretation of the exposure data. Millsite The Shiprock uranium millsite is located in the community of Shiprock, New Mexico on a bench overlooking the San Juan River (Figure 1). Both Shiprock and the millsite are located on the Navajo Indian Reservation. About 1.5 million tons of tailings were produced on the millsite during its operation from 1954 to 1963. The tailings were pulped with waste process fluids and water, and discharged to form two tailings piles. The piles (ponds, dams) were formed with earth starter dikes and the dikes were then raised using the separated sand fraction of the tailings. The slime fraction of the tailings were discharged into the diked impoundment. The mill was shut down and partially dismantled before the lease expired in 1973, and the remainder of the mill and tailings reverted back to the Navajo Tribe which was the lessor. Portions of the millsite were then occupied by the Navajo Engineering and Construction Authority (NECA), a tribal enterprise. In addition to its regular activities, NECA established an on-site training school for heavy equipment operators. The trainees principally used the south tailings pile as a practice area and spread the tailings into a 10 hectare row of raffinate ponds located along the southwest side of the millsite. Overall, the training activities inceased the effective area of the tailings piles from 20 to 35 hectares. Another 56 hectares were contaminated with wind and water eroded tailings. Exposure Conditions Persons decontaminating a millsite may be subject to radiation exposures from several sources. Only whole body gamma exposures are discussed in this report. These exposures are arbitrarily divided into three levels: high, intermediate, and low. The levels are related to areas in which the decontamination work was being done and have no connotation concerning imminent hazards. High exposures would result when persons were working with raw tailings, and intermediate exposures would occur when persons were working in the ore storage and mill yards. Low exposures would result from working in areas where surface contamination exists from wind and water erosion. [ ] The millsite and its contaminated environs were divided into major areas to facilitate the decontamination work (Figure 2). Areas A, B, and C are defined as perimeter areas containing surface contamination. Work in these areas was expected to result in low exposures. Areas D, E, and F are the

Jan 1, 1981

By S. P. Hansen

Gravity sedimentation is one of the most widely used processes for separating solids from liquids whether it be for ore and mineral processing or for treating municipal sewage or industrial wastes. Investment in sedimentation equipment can represent a significant portion of the total capital costs associated with a processing or treatment facility. In spite of the importance of sedimentation, little attention has been devoted in recent years to improving this equipment by applying the basic principles involved in sedimentation. In the water and waste treatment field, design criteria established one half-century ago is still the accepted standard and in reflection of this lack of progress, sedimentation and thickening equipment has remained virtually unchanged. The primary purpose of this paper is to present and describe a new innovation in gravity sedimentation which has been applied to water and wastewater treatment and could definitely have application in the field of ore and mineral classification. A secondary object is to introduce the mixed media filter which has been widely used to treat municipal drinking supplies, industrial process water and to provide tertiary treatment of sewage and industrial wastes. The tube-type clarifier was developed primarily to be applied in the field of water and waste treatment where it was found that it could be used to considerably reduce the size and cost of clarification facilities. A logical extension of the tube clarifier would be to the area of minerals classification, ore separation, and for treating waste water associated with these activities. In water treatment practice, most clarification processes are followed by a filtration step to provide further polishing of the water prior to use. This paper will also discuss the mixed media filter which is graded from coarse to fine in the direction of filtration and is capable of operating at high filtration rates and with greater applied suspended solids loading than other filter designs while providing a high qualify filtrate.

Jan 1, 1970

By C. Newman, R. C. Ray

Originated and developed in the civil tunneling industry, the Ground Reaction Curve (GRC) has provided a robust methodology for evaluating and designing ground support in both tunnels and underground mining scenarios. This paper presents a preliminary assessment in the utilization of the GRC concept for the evaluation and design of the pillar-support system with respect to overburden stress and displacement. This initial assessment will be based on and backed by past research on this topic. Underground mine instrumentation is planned for a longwall mine in the Appalachian coal field based on the research and findings in this paper to support the postulated hypothesis. INTRODUCTION Since the early 1970’s, the mining industry has evaluated the structural stability of a pillar by dividing an approximated pillar load by an approximated pillar strength. While this design methodology has served the industry well in the past, as modern mining operations continue to develop in more complex geological and geometric conditions coupled with market economics, industry professionals are in dire need of a modified stability assessment approach which considers both the stress condition and material displacements. Within the civil tunneling industry, the GRC approach has been successfully utilized in designing underground support measures that enhance the stability of an underground excavation. Through the incorporation of current industry knowledge and understanding of ground and support behaviors this paper looks to investigate into preliminary assessment for the development of a Modified Support Response Method (MSRM) to further improve the analysis of local and global underground stability. CURRENT PILLAR DESIGN METHODS AND THEIR LIMITATIONS Globally, multiple pillar design methods have been utilized in the design of underground excavations. Each of these methods approaches the calculation of pillar stability a little differently with respect to material properties, underground geometries and stress conditions. Analytical solutions can be used to determine the strength of homogeneous materials like concrete, but not in case of non-homogeneous and non-isotropic mineral deposits in a mine. These equations are often derived using empirical methods. Pillar strength is defined as the maximum resistance of a pillar to axial loading (Brady & Brown, 1985). The strength of mine pillars is typically estimated through indirect methods. In the past, researchers have correlated the strength of a given size and width of a rock specimen to the strength of a mine pillar. The first study on the effect of geometry on rock strength was done by (Bauschiger, 1876) on Swiss sandstone samples. Since then several empirical equations to determine pillar strength had been published by many researchers like (Bunting, 1911), (Griffith & Conner, 1912), (Greenwald, Howarth, & Hartmann, 1939), (Holland & Gaddy, 1957), (Evana, Pomeroy, & Berenbaum, 1961) and (Holland C. , 1964).

Jan 1, 2019

By C. E. Jordan

Direct digestion of phosphate ores by the acid-alcohol method offers improved leaching selectivity for the exclusion of iron and aluminum in the product acid. The leaching kinetics of this process will have a major role in the eventual application of this technology. The Bureau of Mines investigated apatite dissolution to determine the reaction rate and mechanisms of the leaching kinetics. The dissolution kinetics were monitored on various sized fractions of pure apatite. The "shrinking-core" kinetics model was applied to the data to determine the rate controlling mechanisms. For each size fraction, the initial reaction rate was controlled by the dissolution reaction. After an hour the dissolution rate slowed indicating a diffusion controlled reaction caused by the formation of calcium sulfate hemi-hydrate coating on each particle. For complete dissolution of the apatite, the phosphate rock should be ground to near 10 µ m size.

Jan 1, 1993

The Gosowong epithermal quartz-adularia vein, in the Halmahera magmatic arc, is a new discovery in an area of primary tropical rain forest with no history of gold mining or mineralization. The newly recognized mineral district also contains a number of other epithermal vein systems, two centres of porphyry Cu-Au mineralization, and a number of argillic and advanced argillic alteration zones that may be related to underlying mineralization. Gosowong was discovered and tested through the application of basic exploration techniques including drainage sampling, soil sampling, trenching, magnetics, IP, and diamond drilling. Lapse time from the initial reconnaissance discovery of a stream sediment anomaly to the release of inferred resource estimates of approximately 1.0m ounces was just over 3 years.

Jan 1, 1997

By N. B. Prenn

Many recent projects have been developed and mined based upon imaginary reserves. Imaginary or "geo-fantasy" reserves have cost many companies millions of dollars. The significant and varied technological advances in the mining arena have done little to curb reserve calculation problems. These advances may have served to increase the prevalence of reserve problems by putting more tools in the hands of personnel not properly trained or experienced in reserve estimation. This paper will discuss potential problems related to calculating reserves, which include: SAMPLING ERRORS -obtaining a representative sample. -Decay analysis of wet RC drilling -Bias introduced by sample preparation. -Assay bias; Coarse gold. -Specific gravity samples. GEOLOGICAL ERRORS -structural boundary definition. -Separation of high grade and low grade zones. -Incorrect continuity assumptions MODELING ERRORS -Too much influence of high grade samples. -Improper method of calculation. -Assumed range of influence. -Errors in the data. ENGINEERING ERRORS -Inaccurate assumptions. -Inadequate metallurgical testing. -Designed bottlenecks.

Jan 1, 1992

By J. M. Van Langen

In 1965 Hoogovens was looking for additional capacity for burden preparation in the order of 2,5 to 3 million metric tons per annum of some kind of optimal blast furnace ore feed. In principle four solutions offered them-selves for further investigation: 1. purchase of screened ore and/or run of mine ores with the provision of a corresponding ore screening capacity on the blast furnace site; 2. manufacture of sinter; 3. purchase of pellets; 4. manufacture of pellets. After studying the technological, technical, economical and commercial factors Hoogovens decided for the last mentioned possibility. Before taking this decision not only a great number of different mixtures of iron ore were tested, but during a long period in one of the big blast furnaces a number of tests were also executed with purchased pellets from South and North America. It was found, that using 50% acid pellets with 40% basic sinter a coke rate saving of 25 kg per ton hot metal (50 lbs/net THM) and a production gain of 15% could be obtained as compared with a full sinter practice. With some pellets it became clear, that due to properties, commonly referred to as swelling, we got very poor furnace performances; so in studying the production of pellets, pellet quality should be regarded as the most important aspect of the problem.

Jan 1, 1972

By Michael J. Miller

The demand and supply of wollastonite has gone through a dynamic period in the 1990's. A 10% -15% growth rate of demand stimulated interest in evaluating new projects. However, the mid-1990's brought declining prices for commodity applications and natural barriers to entry for technical applications, making many of these potential projects uneconomic. Successful projects that were brought to market were done so by incumbent producers. This work examines the competitive structure of the wollastonite market by evaluating the strategic decisions of the industry leader, NYCO Minerals Inc., and a new market entrant, Orleans Resources, in an attempt to identify the environmental threats and opportunities of this industry. Results suggest new entrants like Orleans Resources face significant entry barriers for technical applications, while NYCO Minerals could improve its profitability by having less exposure to commodity applications.

Jan 1, 1999

By A. J. Kwitowski

Teleoperation is a technology that can provide significant health and safety improvements in mining, by relocating machine operators hundreds of meters away from the face area. The U. S. Bureau of Mines (USBM) has recently developed a teleoperation system for continuous mining and haulage equipment. This system features near-real-time closed-loop control. A prototype system was developed and demonstrated on the surface. This system could be used in thin-seam applications down to 914 mm. Details are provided on the developed teleoperation system, results of testing, and expected, future applications of this technology for improved safety.

Jan 1, 1994

By Gordon Clark, Basar Arioglu, Zlatanic. Sanja, Nasri Munfah, Togan. Tolga

"The 13.2 m external diameter double deck Istanbul Strait Road Tube Crossing is one of the most challenging underwater tunnel projects in the world. Subjected to 11 bars of hydrostatic pressure, variable geology, and being in a very active seismic area, the execution of the project required innovative solutions, sophisticated construction techniques, and prudent risk management approach. The 5 km tunnel consists of 3.4 km TBM bored tunnel, 1 km twin NATM tunnels, and cut and cover sections. The project is being delivered in a Build-Operate-Transfer (BOT) contract in a public-private partnership. The technical challenges, coupled with financial and commercial risks required the implementation of sophisticated risk management tactics including the provision of Independent Design Verification. Presently, the project is in its advanced stages of construction with a recent successful TBM breakthrough on August 22nd 2015. The paper presents the technical challenges of the project from the design, construction, and risk management aspects and provides the status of the construction. PROJECT BACKGROUND The $1.245 billion Istanbul Strait Road Tunnel Crossing project, dubbed the Eurasia Tunnel, is one of several major infrastructure projects being implemented in the Republic of Turkey in a public-private partnership approach. The project provides a direct and easy connection between the Anatolian (Asian) side of Istanbul and the heart of its historical district on the European side across the Bosphorus Strait which connects the Black Sea with the Sea of Marmara. Upon its completion in 2017, the project will improve connections to a wide network of motorways on both sides, increase capacity across the Bosphorus by 100,000 vehicles a day, reduce congestion and save motorists an average of 45 minutes of commuting time in each direction, and bringing significant economic benefits to the city and the region; it will ease traffic across the strait, reduce congestion, decrease pollutants and emission while maintaining the historical silhouette of the city. Figure 1 provides a general view of the project location and alignment. The overall project consists of three parts totaling 14.6km. Parts 1 and 3 consist mainly of widening existing motorways, providing connections to existing roads, reconstructing local bridges and underpasses on the European and Anatolian sides respectively. Part 2 is the tunnel crossing across the Bosphorus; it is the most complex part of the project with the greatest challenges and risks. Part 2 is 5.4 km long consisting of 3.4 km of 13.2m external diameter TBM bored tunnel under the Bosphorus Strait, 1-km of twin NATM tunnels on the Asian side, cut and cover transition boxes in the Asian and the European sides and depressed approaches on both sides. In addition, this segment includes the toll plazas, ventilation buildings, and the tunnel control and maintenance facilities."

Jan 1, 2016

By Pawan Bharadwaj, Wim Mulder, Thomas Tscharner, Guy Drijkoningen, Rob Jenneskens

"The Earth’s properties, composition and structure ahead of a tunnel boring machine (TBM) should be mapped for hazard assessment during excavation. We study the use of seismic-exploration techniques for this purpose. We focus on a seismic system for soft soils, where shear waves are better and easier to interpret than compressional waves, as has been shown over the last decade. The system is intended to be deployed on the machine’s cutter head, with a few seismic sources and sufficiently many seismic sensors to tackle spatial variability and noise characteristics. An important property of the newly developed system is its ability to process data with very little human interaction. Images need to be available in near real time, without human interactions slowing down the imaging process. This can be achieved by employing Full Waveform Inversion, which minimizes the difference between modeled and observed data. Because this method may suffer from local minima in the cost function if the data lack low-frequency information, we employ a dedicated seismic source that can generate sufficiently low frequencies for the relevant length scales. With data acquired in a number of field settings that mimic realistic TBM configurations, we show that the designed seismic system can successfully look ahead of the TBM and offers a valuable capability to support decision-making during tunnel excavation. INTRODUCTION While excavating a tunnel with a Tunnel Boring Machine (TBM), the geology and the ground conditions along the planned tunnel trajectory need to be investigated in order to safely and efficiently carry out the underground operations. This entails detecting the occurrence of boulders, foundations, pipes and faults, necessary to prevent hazards and time-consuming delays in the tunnel boring operations. In order to facilitate ground prediction ahead of a TBM, techniques as used in seismic exploration can be deployed. Two components common to seismic-exploration techniques are data acquisition and processing, the latter including inversion. We will discuss each of these for the application to tunnel excavation with TBM, in particular for soft soils."

Jan 1, 2016

The Kinross DeLamar Mine has been operated for more than 17 years producing precious metals dore' from ores, principally silver bearing with associated gold co-products. In late 1995 a new orebody was commissioned, the Stone Cabin orebody, and the site began a phased shift from silver dominance to gold dominance in terms of precious metals revenue. The Knelson Concentrator was selected to remove gold from a portion of the cyclone underflow stream in the grinding circuit. This paper describes the development of the flow sheet, specific mineralogical impacts on Knelson product and downstream materials, and impacts on mine/mill grade reconciliation.

Jan 1, 1997