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By D. A. Bulled

• "What does it look like?" - describes the appearance. • "How does it work?" - outlines the operation. e "Why does it work?"- explains the principles. • "What about controls?" - indicates possible automatic systems. • "How is it sized?" - discusses the necessary testwork and evaluation. • "What are the results?" - demonstrates test and operating results. • "What's the benefit?" - concludes with gains for the user.

Jan 1, 1999

By Michael Rieber

Capable of establishing a net present value of zero over a short period of time small mines, though not simply scalers of large operations, minimize market risks and reduce investment capital. Particularly now they are relevant to LDC development. Small mine concepts are reviewed with emphasis on sizing, speed, and LDC problems. The special problem of gold and the precious metals is examined with respect to mine evaluation. Small mine analysis is introduced with emphasis on the financial model including gold price forecast considerations.

Jan 1, 1987

By X. Wu, M. Karfakis, E. Topuz

The generalized ventilation network problems encompassing both natural and controlled splitting networks, is formulated using a nonlinear nonconvex programming model, which has not yet been solved satisfactorily. This paper presents a methodology which can deal with the problem. The proposed methodology converts the nonlinear problem into a linear problem, by using special ordered sets of variables, and optimizes it by a modified branch and bound technique. The global optimality of the methodology and its applicability to different cases are investigated

Jan 1, 1991

By A. Pavlides

The purpose of this study is to compare estimation methods for lignite reserves at the Amyndeo mine and to provide a map of the estimated thickness of the coal seams. The reserves are first estimated with the method of Voronoi diagrams, using a group of mirror points to close the polygons around the boundaries of the mine. The second estimation method is based on Ordinary Kriging using the Spartan variogram model. Finally, the reserves are estimated by the mean lignite thickness value of the drill-hole data Two data sets are investigated. The first one corresponds to an exhausted part of the mine. The derived reserves estimates are compared with the actual data obtained by the Public Power Corporation (PPC) to validate the analysis. The second data set extends over the entire mine, and it is used to derive an approximate estimate of the total lignite reserves. A geostatistical analysis of the total layer thickness is performed. An interpolated kriging map of the total thickness variation is produced accompanied by a map of the kriging uncertainty.

Jan 1, 2008

By Li. S. D., R. X. Zhang, K. M. Li, Y. D. Zhang, Y. J. Hou, S. G. Li

A computer aided design software system for long range coal surface mine planning has been developed by the authors. The system is composed of two subsystems: a coal deposite sub- system and a long range mine planning system. The geological parameters are estimated and a grid model is formed, then a 3-D block model can be developed for mining design. The long range surface mine planning system is based on oriented graph simulation and combined approaches to seek for the optimal deign alternative. This mining model consists of a number of sub-models to realize mining design functions such as: calculation of mining volume and coal quality by graph scanning; determination of operational stripping ratio by interactive design; varification of annual coal production; delimitation and development of dumping site; optimization of material flow direction and volumes by Linear Programming; surface mine production scheduling by interactive iteration; etc. The software package was developed on PC computer 486. It features classified menu guide, module structure, figure and graph representation on the screen and flexible interactive functions. This system has been applied to an open cut coal mine and predicted functions have been obtained.

Jan 1, 1996

By Niall Weatherstone

Introduction Risks & Rewards of a Mineral Reserve Life History of a Mineral Reserve Estimate Risk Assessment & Management Mineral Resource & Reserve Estimation Good Practice Mineral Resource & Reserve Reporting Conclusions

Jan 1, 2003

By N. L. Piret, R. J. Wesely, A. E. Melin, A. D. Zunkel

At the end of the sixties new iron precipitation techniques as jarosite, goethite or hematite brought about the new generation of electrolytic zinc plants, thereby terminating the multitude of existing neutral leach residue treatment schemes. Since the eighties, increasing environmental impact considerations urge the conversion of these contaminated waste generating precipitation processes to techniques which either produce environmentally acceptable residues or minimize their formation thereby generating iron-bearing byproducts. Technologies identified and economically assessed include the hematite process either suitably improved or with subsequent upgrading, the iron extraction process and the direct smelting of neutral leach residue to slag and fumed zinc oxide.

Jan 1, 1993

By Sergey G. Pushkin, Eugeny L. Schastlivtsev, Anatoly A. Bykov

Three years ago the authors and a group of assistants began to develop a GIs-system for integration of comprehensive eco- logical information to be linked to geographical maps of Kuzbass region. And now we have got the working system and some first results that the present paper deals with.

Jan 1, 1996

By Hemant Agrawal, Arvind Kumar Mishra

Rock breakage using blasting is one of the important operations of the mining industry. The delay timing decides the initiation sequence of holes in the blasts and is a crucial factor to improve the overall blast performance. Blast-induced ground vibration is an undesired yet unavoidable outcome of blasting. Peak particle velocity (PPV) is commonly used to measure the magnitude of blast-induced ground vibration. Channelization and better utilization of explosive energy delay are provided between blast holes using initiating systems. The use of different initiation systems even on the same site results in a very significant difference in the values of PPV generated. Due to scattered delay timings of pyrotechnic detonators, the scaled distance predictor equations obtained become unreliable. The error/scatter in delay timing leads to overlapping of holes and hence increases in maximum charge per delay. In this paper, an analytical approach has been discussed to measure the overlapping of holes during blasting with initiation systems having inherent cap scatter. The analytical approach will be calculating the probable overlapping of holes due to scatter in delay timing and will help blasting engineers to understand the variation in maximum charge per delay due to pyrotechnic based initiating systems. In this study, a total number of 102 blasts were conducted using different initiation systems at two different opencast coal mine and 221 corresponding blast vibrations events were recorded.

Nov 10, 2020

By Megan Badonie, Devlon Shaver, Evan J. Owen, Virginia T. McLemore, Jakob Newcomer

Critical minerals are becoming more important in our technological society because they are used in many of our electronic devices, batteries, and magnets. In New Mexico, low to moderate concentrations of critical minerals are found in Late Cretaceous coal and related strata in the San Juan and Raton Basins. These rocks are being characterized as part of the DOE’s CORE-CM (Carbon Ore, REE, and Critical Minerals) program. The New Mexico coal, humate, and clinker deposits are relatively low in REE (<325 ppm TREE), Li (<90 ppm), V (<168 ppm), Co (<51 ppm), Ni (<108 ppm), Zr (<557 ppm), and many other critical minerals compared to normal economic deposits. Some of these rocks are enriched in Al2O3 (<40%) and Sr (<3740 ppm), both critical minerals. Common minerals hosting the critical minerals in these rocks include clay minerals, zircon, and rutile/anatase. As the demand for some of these elements increases because of increased need and short supplies, the dollar value per ton of ore rises, enhancing deposit economics. Ultimately, economic potential will most likely depend upon production of more than one commodity, maybe even from coal, humate, and clinker deposits.

Feb 1, 2024

By Joseph R. Hatch

During the past ten years detailed elemental analyses of approximately 8,000 well-documented samples of coils in the United States (including Alaska) have been produced by the U.S. Geological Survey and the various State geological surveys. Examples of data listings include Swanson and others (1976) Gluskoter and others (1977) Hatch, Affolter, and Davis (1979), and Wedge and Hatch (1980). These analyses serve as a basis for evaluating elemental abundances in coals from the various coal province, regions, and fields. When combined with additional geological and geochemical data, some of these analyses give insight into when certain elements were introduced into coals, and which physical and geochemical parameters are most important in determining coal elemental composition.

Jan 1, 1982

By Kevin Schraden, Andrea Pezzi

environmental and social/political changes the world is currently experiencing. Three of major challenges facing the mining industry today are: water scarcity, unpredictable weather conditions that generate a risk of tailings dam failures as well as the correlating social pressure and government regulations that prevent the development of new or expanded tailings dam projects. It is estimated the total number of active, inactive and closed storage facilities globally is over 8,500 containing over 217 km3 of tailings (46% are from copper mining)1 which at some point will need to be addressed. Technologically, there are several solutions for tailings management, including conventional ponds, thickened tails, paste backfill and filtered dry stack tailings. The use of pressure filters, for tailings dewatering is currently being evaluated and often selected as the preferred technology where dry stacking is the chosen solution for residue disposal. This is mainly due to the pressure filters ability and flexibility to address and achieve the current challenging aspects of tailings processing including: • Extremely high capacities of >80,000 dry tons/day • Lower ore grades which require finer grinding and result in a higher amount fine fractions and clay content • Residual moisture targets required for the geotechnical specifications for dry stacking

Feb 1, 2024

In order to reach a large, untapped reserve of high-quality coal, D8 Cloverlick mine proposed to mine a corridor nearly 2,000 ft deep beneath the Benham Spur of Black Mountain, Kentucky’s highest peak. D8 Cloverlick mine was extracting the Owl seam, but the corridor’s route lay approximately 70 ft above century-old mine workings in the C–(Darby) seam. Adding to the concern, three serious coal bursts had recently occurred in nearby Owl seam workings.

Jan 7, 2020

By John G. Groppo, James C. Hower, Cortland F. Eble, Rick Q. Honaker, Alireza Valian, Stephen F. Greb

Coal and coal combustion byproducts are potential candidates for alternative resources of REEs (rare earth elements). The Illinois Basin is a major coal-producing district in the USA, but little work is available on speciation of REEs in the basin’s coals. In this study, a total number of 382 samples from known locations in the Illinois Basin coal beds were acquired, analyzed for their REE contents, and investigated for any spatial trends or chemical correlations. This study includes Springfield, Herrin, and Baker coal beds—the most heavily mined coals in the basin. An average coal ash from the basin contains 320 ppm REE, with Baker being the highest (407 ppm on average). However, the distribution of REEs in the coal beds was laterally and vertically heterogeneous. A number of trends were found in the REE variations. The most important trend was the relationships of the REE concentrations and fractionations with the distance from the syndepositional sandstones. The total REE concentrations were higher in the proximity of the sandstones, likely due to the increased deposition of detrital material. This increase was the most significant in Springfield coal (90%) and least in Baker (6%). Those coal samples from the Springfield and Herrin coal beds distal from the syndepositional sandstones had a heavy to light REE ratio (H/L ratio) of 0.40 on average, whereas in proximal locations, the ratio was dropped to an average of 0.30. This trend was not significant in the Baker coal bed. In general, higher mineral matter in the coals was associated with higher REEs. In coal preparation plants, refuse rocks can have up to 360 ppmREE. However, the ashes of the cleanest coals had higher REE levels. Such ashes also have a higher ratio of heavy to light REEs. The highest REE concentrations were found in the claystones and the shales associated with the coal beds. Since the naturally occurring calcite, quartz, and pyrite samples were depleted in REEs, an association of REEs with the clay minerals can be suggested.

Jul 20, 2020

By David A. Sterling

Approximately 50 percent of the uranium resource of the Free World is in deposits of Precambrian age, principally in lower Proterozoic conglomerates in Canada and South Africa (Uranium Resources, Joint Report, ENEA and IAEA, 1967). Most of the uranium resource of the United States is in Mesozoic and Cenozoic continental clastic sedimentary rocks that fill intracratonic basins. The Atomic Energy Commission is investigating the distribution of uranium and thorium in the Precambrian of the Western United States and the relationship of, time-space-facies patterns of uranium and thorium enrichment in the Precambrian to the major resources of uranium in the Mesozoic and Cenozoic host sedimentary rocks. This paper summarizes the results of preliminary studies of the Precambrian in the Southwestern United States including New Mexico, Arizona, southern Nevada, and southern California (Fig. 1). The host rock provenances for the major uranium resources in epigenetic deposits of Mesozoic and Cenozoic age in the Western United States were in areas of extensive Precambrian exposure along the eastern margin of the Phanerozoic geosynclinal belt (Fig. 2). Mesozoic continental clastic sediments in the Colorado Plateau contain about two-thirds of the uranium resource of the United States. These sediments formed from detritus derived from the Mogollon highland in the Southwestern United States where the Precambrian was extensively exposed (Stewart, et al., 19593 McKee, et al., 1959; McKee, et al., 1956; Craig, et al., 1955) (Fig. 2). A genetic relationship may exist between this provenance and the major uranium deposits of the Colorado Plateau. The Precambrian might be equally important in the genesis of uranium deposits whether the most important process in the formation of these deposits was the leaching of low-order intrinsic amounts of uranium from Precambrian granite or from Mesozoic pyroclastics derived from syntexis of the Precambrian basement rocks (Malan, 1968).

Jan 1, 1969

By Aladar B. Dory

INTRODUCTION Practical experience in mines with known presence of radon daughters in the mine atmosphere in Canada and elsewhere shows that a very high concentration builds up in an unventilated dead end heading. As Holaday et al1 observed, even a minimal air movement results in a drastic reduction in radon daughter concentration. It is therefore obvious that the main objective of radon daughter control in the working environment is to design the ventilation system providing an optimized flow of fresh air into the workplace, resulting in acceptable climatic conditions and achieving radon daughter concentrations resulting in exposures as low as reasonably achievable. BASIC OBJECTIVES Large mining companies, having extensive material resources and professional expertise, have utilized elaborate electrical modelling in the design of mine ventilation systems as early as 1950 (coal mining industry in Europe) and with the advance of computer modelling techniques, their utilization in ventilation systems design is on the increase. Unfortunately, these methods are usually not available to small mining companies and even the large companies might not achieve the fullest benefit from utilizing them, if proper limiting factors are not considered in the modelling. When an evaluation of a ventilation system of a mine is undertaken in literature, a measure of the amount of air supplied underground per one ton of ore mined is used as an indicator of the efficiency of the ventilation system. Yet, even the greatest amount of air forced into the mine might not result in an acceptable working environment if a proper distribution of this air into individual working places is not achieved. The volume and the age of the air are probably the two most important factors in achieving acceptable radon daughter concentrations in the workplace, but other factors also have to be considered. DIRECTOR MINE - ALCAN, NEWFOUNDLAND FLUORSPAR WORKS ST. LAWRENCE, NEWFOUNDLAND, CANADA Ventilation To illustrate the effects of the design of the ventilation system on the control of radon daughter concentration, let us review the gradual development of the ventilation system of this mine from the earlier years of its development up until its final years of operation. This mine, located near the community of St. Lawrence on the south coast of Burin Peninsula was developed in the late thirties and reached full production by 1942. Unfortunately as was customary at that time, the only source of ventilation was a natural draft. The mine was extremely wet, and no significant attention was initially given to possible health effects of dust. It was not until the mid-fifties, when a number of cases of silicosis had surfaced, that de Villiers and Windish2 observed a significant increase of lung cancer incidence among the miners in comparison to its incidence among the general population of Newfoundland. Suspicions regarding radiation as a cause of the lung cancer were expressed, but it was only in surveys taken in late 1959 and early 1960 that Windish3 and Little4 established the presence of radon daughters in the mine atmosphere in very high concentrations. Windish, de Villiers and Hurley suggested that the most likely source of the radon in the mine was the mine water which dissolved radon during its passage through the granitic country rock in the surrounding geological area. This conclusion was confirmed by analyses of water from various areas of the mine by the Atomic Energy Canada Limited laboratories. The radon values in the samples varied from 4,240 to 12,850 pCi/L5. Following the discovery of the presence of radon daughters in the mine, the company took speedy action to install mechanical ventilation for the mine. The system was not designed as a total unit, but fans were installed rather on a trial and error basis. The basic system installation began in March 1960 and was completed by 1962. It remained basically unchanged with only minor modifications until August 1973 when a wholly new, redesigned ventilation system was implemented. A schematic section of the mine and its ventilation system for the period prior to March 1960 is given in Figure "A", for the period 1960-1973 in Figure "B", and for the period after August 1973 in Figure "C". The ventilation system prior to 1960 is not known. All workings of the mine were ventilated only by natural ventilation. If any measurements of airflows at different or any times of the year ever existed, no records have been preserved. The very minimal natural ventilation was augmented by "blowing" air from compressed air supply lines and exhaust air from drills. It is known that the compressor capacities of the mine were limited and therefore no significant air movement was probably created by the "blowing".

Jan 1, 1981

By S. P. Banerjee

There has been a phenomenal increase in production of coal from opencast mines in India. At the same time environmental problems caused by mining are receiving greater atttention. Deterioration in ambient air quality due to increased concentration of suspended particulate matter (SPM) in and around an opencast project is a major problem. Some measured values of SPM level around opencast mines in diff coalfields show that in many cases the TLV of 500 ug/m^3 is exceeded. The impact of dust emission from a mining project on surrounding areas are estimated by using computer models for air pollution dispersal but such treatment suffers from errors in predicting the dust load and failure to take into account the terraced nature of the opencast mine site. The haul roads have been identified as the most prolific source of dust and some recent trials on haul road dust consolidation in Indian mines are mentioned in the paper. Statistics regarding pneumoconiosis cases in Indian coal mines for the last decade are presented to show an increase in reported cases and a gist of the recently amended regulations on the subject of precaution against dust is mentioned.

Jan 1, 1991

By Yiyin Ma, Yuqi Chen

Based on two in-situ measurements and mathematical analysis, the micro-climate in a large central underground pump and power station has been discussed in this paper. It is found from the research that the "semi- infinite" body model in the general heat transfer can closely represent the heat exchange process in the air flow-surrounding rock-adiabatic intermittent heat source complex in the station. Finally, computer simulations were made to calculate the micro-climate in a similar pump and power station where power machines operate intermittently. The simulation results are quite satisfactory. It can provide useful information for decision- making in the air conditioning of such stations.

Jan 1, 1991

By Paul Basinski

The Northern Reese River Valley is in west-central Lander County approximately 31 miles north of Austin, Nevada in the north-central Basin and Range Province (Figure 1). Authigenic zeolites, which were previously undescribed in the literature, are voluminous in this small sedimentary basin. Uranium mineralization is also abundant in this study area. Until now, what we believe to be cause and effect have not been put together. X-ray diffraction, differential thermal analysis, and scanning electron microscopy reveal clinoptilolite, erionite, analcime, and minor chabazite to be present (Figures 2, 3). Assays show uranium to be present in thicknesses up to 0.7 meters at amounts up to 0.10% eU308. The sediments in the Northern Reese River Valley belong to the Mio-Pliocene Humboldt Formation equivalents. This formation consists largely of tuffacious lacustrine and fluviatile sedimentary rocks. Mudstone is the dominant lithology and intercalated thin zeolite strata (usually less than 0.6 meter thick) are present. Zeolites in the Northern Reese River Valley were diagenetically derived from rhyolitic glass deposited in a shallow, saline-alkaline lake under arid to semi-arid conditions. Clinoptilolite from the study area was K-Ar dated at approximately 4.7 + 0.5 million years which corresponds to Middle Pliocene age (Krueger and Basinski, in press). This age is further substantiated by Middle Pliocene mammalian fauna collected in the vicinity by Deffeyes (1).

Jan 1, 1979

By P. T. Perdue, F. F. Haywood

INTRODUCTION Monitoring devices used for detecting and measuring airborne radon in mines are limited due to the rugged environment in which they must operate. Personnel monitors now available are either passive or require filters and an air pump. Area air monitors usually have bulky batteries or require electric power service to the instrument. Thus, there are few instruments presently in use in mines capable of discriminating between the various radon isotopes and their daughters. Occasionally it is desirable to determine which radon daughters are the principal dose contributors in mine air. In some areas, such as the Elliot Lake mine in Canada, there exist sizable quantities of 220Rn in the mine air due to 232Th in the ore (Cote and Townsend, 1981). Since there has been recent interest in radon daughters in homes and factories, as well as caves and mines, methods and instrumentation are being developed to address these cases. Some of these methods can be employed in uranium mines. Although there have been very few determinations of the three radon isotopes (222Rn, 220Rn, and 219Rn) and their daughters made in uranium mines, these isotopes have been measured in process buildings and in private homes under circumstances that suggest these isotopes could also be present in uranium mine air (Perdue, Leggett, and Haywood, 1980; Yarborough, 1980) METHODS Cryogenic air sampling was developed about 15 years ago (Rasmussen, 1972) to concentrate various airborne chemicals for later fractional distillation and measurement of various organics using gas chromatography. A version of this technique has been developed to measure tritium, krypton, and other radioactive gases in nuclear power station buildings (Anon, 1980). In this method, fractional distillation is used in conjunction with various detectors to identify the radionuclides present. The cryogenic method to be discussed here was developed at Oak Ridge National Laboratory (ORNL). It uses the liquid air accumulated in a sampling device for a direct analysis of all gamma-ray emitters present. The air sampler (Fig. 1) could be employed in a mine to liquefy air, using the difference between the point of liquefaction of air (~80 deg. Kelvin) and the boiling point of liquid nitrogen (77 deg. Kelvin) to liquefy an air sample. By using a proper orifice at the entry to the sampling vessel, air of any dust concentration and relative humidity [ ] may be sampled. The energy for sampling is provided by the slow evaporation of the liquid nitrogen; no other power source is required. This type of sampler could be used to augment the usual filter and pump, or passive system presently employed to estimate personnel dose from radon daughters. It would also allow measurement of any combination of daughters from the three radon isotopes. Upon completion of sampling, the sampler is closed and removed from the mine. This sampler, with its liquid air contents maintained by the slow evaporation of liquid nitrogen, is taken to the place of measurement. There, the sampler is opened, the accumulation of water and ice in the neck is chiseled down into the liquid air, and the sample is transferred quickly to a precooled counting dewar (Fig. 2). This counting dewar is then placed upon a gamma radiation detector; we recommend a high purity germanium detector. A determination of all the radon daughters can be made in 1 to 4 hours after the sample is taken.

Jan 1, 1981