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By Jerry Demchuk, Allan Flemming, Stephan Day

Luscar Ltd. is currently developing open pit mining plans for the Telkwa Coal Project. Most waste rock is predicted to be non-acid generating but a proportion (less than 20%) is potentially acid generating. The waste management plan includes in-pit and ex-pit disposal of blended and till-capped waste rock, segregation and in-pit encapsulation of strongly potentially acid generating materials, and in-pit underwater disposal of coarse and fine tailings. The paper will present the steps used to design the waste management plan including the development of geochemical design criteria using various tests and theoretical and practical knowledge of waste behaviour.

Jan 1, 2000

'IM existing predictive methods were chosen for evaluation; an influence function (Bals Theory) and a profile function (hyperbolic). These ere applied to several field measured subsidence profiles over United States coal mines. The effect of homogeneous versus non-homogeneous overburden on surface subsidence is demonstrated and the utilization of Bals Theory as a subsidence predictive method for both types of overburden is examined. The major factor affecting subsidence profile characteristics is the migration of the inflection point toward the centerline of the longwall panel. A computer program was written to aid in the analysis.

Jan 1, 1982

By J. R. Gump

The term "rare earths" is used to designate a group of elements, Numbers 57-71 which are closely related chemically. They were called "earths" because their oxides resemble those of the alkaline earths, and the designation "rare" was originally applied because of their scarcity. Now many of these elements are known to exist in considerable quantities, and the term "Lanthanide" is applied to this group of elements, because of their similarities to lanthanum, the first element in the group. Many authorities insist on including yttrium, element Number 39, because of its extremely close association with the members of the group in nature and because of its similarity in chemical properties. It has been estimated that the combined rare earth group makes up about five-thousandth. of one percent of the Earth's crust, a higher percent than the common elements, lead, tin, zinc, arsenic, mercury, silver and gold. Cerium is by far the most abundant member comprising about half of the total amount. Yttrium, neodymium, and lanthanum are next in order; samarium, gadolinium, praseodymium, dysprosium, erbium, holmium, and ytterbium are increasingly scarce; while the elements lutetium, thulium, terbium, and europium are extremely rare. The rare earths as a group are metals, usually trivalent, forming basic oxides, and insoluble oxalates in dilute mineral acids. Their fluorides are also difficultly soluble; hence the rare earths or lanthanides may be separated, in general, from other elements by adding oxalic or hydrofluoric acid to a dilute mineral acid solution containing them. The most striking fact which characterizes these elements is the remarkable .similarity in both the physical and chemical properties of their compounds. Their main differences are in the solubilities of their salts and the basicity of their oxides, which vary between that of the alkaline earths and that of aluminum.

Jan 1, 1960

By Eugene F. Casey, John G. Ruggiero

INTRODUCTION Construction of tunnels in urban areas, especially reclaimed areas, pose many problems. The Red Hook Intercepting Sewer Tunnel, Contract 1A is a portion of the Red Hook Water Pollution Control Project located along the Brooklyn waterfront in New York City. This contract required the construction of a 2620 meter long (8600 L.F.), 3 meter (10-foot) diameter soft ground tunnel, eight Tunnel Manholes, nine Regulator structures, four Diversion and Tidegate structures and 765 meters (2500 L.F.) of branch intercepting sewers of diameters between .30 meters (12 inches) and 1.8 meters (72 inches). The construction contract bid price was $62 million with a duration of three years. The tunnel route crosses over five sets of operational twin cast iron subway tubes with clearances ranging from 4.3 meters (14 feet) to as small as 0.35 meters (14 inches). The route of the tunnel traverses historically interesting areas which have been reclaimed over the last 200 years. This paper is a case history describing the contractor's methods utilized to successfully advance the work through the above problem areas. LOCATION The Red Hook Intercepting Sewer Tunnel is located in the Borough of Brooklyn of New York City. The route is

Jan 1, 1981

By Steve Kral

Philip M. Hocker is president of the Mineral Policy Center (MPC), a Washington, DC-based, non-profit organization formed to "address the environmental problems that are caused by mineral development in both the hard-rock mining and onshore oil arenas." Hocker has been involved with resource development and environmental policy issues since the 1970s. He has been a plaintiff in several lawsuits regarding environmental management of federal onshore oil and gas leasing. He was also active in the 1987 campaign to pass the Federal Onshore Oil and Gas Leasing Reform Act. Hocker served on the board of directors of the Sierra Club from 1980 through 1986. He is also a member of SME and spoke at the welcoming luncheon and keynote session of the SME Annual Meeting and Exhibit, Feb. 14, 1994, in Albuquerque, NM. In his role as president of MPC, Hocker has become a major player in the ongoing battle concerning mining law reform. And, while the mining law issue is the most visible and controversial issue confronting the mining industry and MPC, Hocker's organization is also active in clean water reform and other public policy issues that concern natural resource development and the environment. Hocker and MPC invoke a wide spectrum of reactions from the mining industry, most of it negative. Even so, the editors of ME decided that SME members should hear from Hocker his views on domestic mining, including mining law reform, clean water legislation and other environmental issues facing the industry.

Jan 1, 1995

By Robert F. Kaufmann

INTRODUCTION In response to the Uranium Mill Tailings Radiation Control Act (Public Law 95-604, Section 114c), a report has been prepared by the U.S. Environmental Protection Agency (1980) which describes the potential health and environmental effects associated with uranium mine wastes. The author was responsible for the geology, hydrology and aqueous pathways analysis portions of the report. All potential sources of contaminants, solids, liquids, and airborne emissions, which might cause adverse impacts upon the environment or health of nearby populations were considered. Wastes at both active and inactive uranium mines (Hans and O'Connell, 1981) are described and assessed with respect to dose and health effects (Blanchard et al. 1981). The emphasis of this paper is on the liquid emissions and the aqueous pathway. Model uranium mines were developed for surface and underground mines. The model underground mine was placed in New Mexico while the model surface mine was in Wyoming. Development of a generic assessment was complicated due to the inherent variability of uranium mines. Also, most information available relates to uranium mills rather than to mines, or reported measurements were often influenced (biased) by wastes from a nearby mill and did not specifically reflect mine discharges. Consequently, the assessment presented is often based on conservatve (maximizing) assumptions which are identified as such, and which were based on knowledge from field investigations, available literature, and consultations inside and outside the U.S. Environmental Protection Agency. Maximum use was made of available data, supplemented with limited field studies in Colorado, Texas, New Mexico, and Wyoming. PREVIOUS INVESTIGATIONS Stream survey work in Colorado by the Water Pollution Control Commission and the U.S. Geological Survey (Moran, 1974; Wentz, 1974) mentioned a portion of the Uravan Mineral Belt and uranium mines therein, but the work did not emphasize uranium mines. Significant amounts of acidity and total trace metal concentrations were found in streams from 18 different mining areas. Dilution and chemical precipitation below mine drainages decreased concentration and increased the pH. Given enough time and distance, the streams recover naturally, but the accumulations of trace metals in the sediments increase. Field observations in 1971-72 of streams in most of Colorado indicated that approximately 724 km of streams in 25 different mining areas were adversely affected by mine drainage (Wentz, 1974). Discussions of the impacts of uranium mining on water quality or quantity are incidental in numerous impact statements and environmental reports prepared by industry and (or) the U.S. Nuclear Regulatory Commission as an integral part of licensing or relicensing uranium mills. Coverage on mining is usually minor as the principal focus is on milling impacts. The same is true for the recently prepared generic EIS on regulation of uranium milling (U.S. Nuclear Regulatory Commission, 1979). Radiochemical assessment of surface and groundwater in uranium mining districts of New Mexico is done by self-monitoring programs associated with NPDES permits. Also, radiochemical assessment studies have been funded by the New Mexico Environmental Improvement Division and U.S. Environmental Protection Agency. Unfortunately, there has been no concerted effort to prepare broad assessments of the cumulative impacts of mining and milling in areas of interest in Texas, New Mexico, and Wyoming. Critical review and synthesis of these types of data can produce rather useful information. For example, the publication "Water Quality Impacts of Uranium Mining and Milling Activities in the Grants Mineral Belt, New Mexico" (U.S. Environmental Protection Agency, 1975) addresses the groundwater and surface water changes as the result of extensive uranium mining and milling production in a relatively confined area. A more recent report by the Wyoming Department of Environmental Quality summarizes 16 years of aqueous radium and uranium data. The study reports significant amounts of radium-226 and uranium were present in surface water in the Shirley Basin as a result of inadequate mine water treatment (Harp, 1978). In Texas, surface water and groundwater monitoring conducted by industry, as well as by State and Federal agencies, reveals little or no change of chemical quality attributable to uranium mining and milling (Gesell, 1977; Kallus, 1976). This conclusion is based on 586 samples collected from 198 stations over a period of 39 years, but primarily from 1961 to 1975. The State monitoring program by several agencies is continuing, but data reporting and interpretation is lagging. One survey (Itin, 1975) showed that none of the mine water from the 10 lakes that were sampled was suitable for human use. The lakes were also unsuitable for irrigation due to mineralization of the water by sulfate, chloride, and TDS. One of the 10 was suitable for stock watering.

Jan 1, 1981

By John W. Wilson

Every operation connected with the working of a deep-level mine has, to a greater or lesser extent, a direct bearing on the costs of production, and hence, profitability of the mine. If adequate mine planning is not done in the early stages in the life of a mine, considerable expenditure can result from the cost of maintaining mine service tunnels, production delays in stopes caused by poor strata control, distortion of fittings in hoisting shafts, rockbursts and so on. In fact, the optimum profitability of a deep-level, hard-rock mine can only be achieved if the layout of the shaft systems, ore passes, tunnels, stoping areas and other underground excavations are designed to withstand or accommodate the rock stress conditions that will be created by mining operations. In South Africa where the deepest mines in the world are located, access to the underground workings of most deep-level gold mines is via vertical shaft systems and a network of tunnels connecting the shaft systems to the stoping areas. In current practice, there are two basic methods of extracting the gold-bearing reef,* namely, the scattered stoping method and the longwall stoping method. The choice of the stoping method is governed largely by the anticipated gold distribution and payability of the reef in the area, the geological conditions, the degree and complexity of faulting and dyke intrusions, the depth at which the gold-bearing reef is to be mined and the inclination and width of the reef. The longwall system was first introduced at the East 717 Rand Proprietary Mines Limited in 1942 in an effort to combat the rockburst hazard which appeared to increase with increase in depth. This mining method became standard practice on that mine for stoping operations 700 ft. below the surface. Since that date, several deep mines on the Central Rand, East Rand and West Wits gold mining areas have adopted this method.

Jan 1, 1977

By N. S. Margaris

The vegetation of Mediterranean ecosystems is distinguished by its resistance to adverse environmental conditions, and that is the reason for examining the possibility of growing species of this flora in waste disposal sites (WDSs). The survival and growth of vegetation established at a waste disposal site is dependent to a large extent on the qualitative and quantitative characteristics of the material used in the final soil cover. In the Ano Liossia WDS, where extensive remediation work is under way, three areas were examined, which met certain criteria in relation to the age of the underlying waste and the existence of impermeable material in the final soil cover. Laboratory analyses have determined soil parameters and nutrient and heavy metal content. Alongside this, at all three sites a network has been installed to monitor the qualitative characteristics of the gaseous phase of the soil cover material. The results showed the existence of a soil material containing few nutrients and the prevalence of oxygen-poor conditions, accompanied by large concentrations of CH4, CO2 and H2S, at depths of up to about one meter.

Jan 1, 2002

By M. J. McPherson, P. Mousset-Jones, G. Danko, I. M. Konduri, F. Calizaya

The flow of air through a bare rock, underground airway is affected by the size and frequency of the micro- and macro-asperities of the rough surface. The focus of this study is to characterize this roughness using the coefficient of friction, the friction factor and the fractal dimension. The rough surfaces were identified by two sets of 177 and 78 transverse profiles measured by a laser profiler along the length of an underground airway at the Sunshine Mine, Idaho. Based on the measurements, the friction factor was estimated from Atkinson's equation and the coefficient of friction from the Moody diagram, and power series and variography were used for computing a fractal dimension for the airway surface. Significant conclusions are reached relating the effect of error in the measurement of cross-sectional and rubbing surface areas of a drift, on the estimated friction factor for the airway. The potential role of the fractal dimension as an alternative to the friction factor for characterizing the roughness of a mine airway is discussed.

Jan 1, 1993

By J. B. Stockton, D. J. Robbins, E. T. Woodburn

Batch flotation data in an equilibrium cell show that beneficiation improves with froth drainage. The limiting lamella thickness in a well- drained 3-phase coal froth appears to be determined for ultra-fine particles (-45µm) by the d90 particle size. The froth stability is considered to depend on the existence of a very thin liquid film between the outer surfaces of the d90 particles and the bounding bubble interfaces of the lamella in which the particle is held. The dependence of the coalescence rate of bubbles in these froths on the residual surfactant concentration in the lamella liquid is then consistent with stability analyses for two-phase foams.

Jan 1, 1988

By G. Atesok, M. Hancer, M. S. Celik, O. F. Emrullahoglu

Multivalent ions are shown to activate the flotation of colemanite in the presence of sodium dodecylsulfate (NaDDS). Floatation recoveries versus barium ion concentrations exhibit three distinct regions of floatability. Adsorption, zeta potential and solubility mesurements under comparable conditions reveal that Region I is characterized by the uptake of Me2+ ions followed by electrostatic attraction of sulfate ions onto the oppositely charged surface. The improvement observed in flotation recoveries in Regions II and III is ascribed to surface and bulk precipitation of metal dodecyl sulfate onto colemanite, respectively. While the most soluble BaDDS ions yield the highest activation, the least soluble MgDDS achieve the lowest activation. It is postulated that metal ions depending on their solubility products with DDS are capable of activating the boron minerals.

Jan 1, 1993

By M. J. McPherson, P. Mousset-Jones, G. Danko, F. Calizaya, K. You

The friction factor is one of the more difficult parameters to determine in ventilation planning. In practice, this can be estimated from published factors such as those of McElroy. The problem with this approach is that the selection requires some judgement, and the estimated values offer no more than guideline accuracy. This study, examines the effects of four factors on the coefficient of friction for a simulated mine airway. The factors are: airway cross-section, asperity height, flow direction, and cross-cut spacing. The study includes the modeling of a mine airway and the evaluation of the results from 13 experiments on flows of air over rough surfaces. The model, physically represented by a wind tunnel, includes a rough surface section which can be modified to simulate mine airways of various shape and asperity height. Most of the experiments were performed under controlled flow conditions during which the Reynolds number was varied between 50,000 and 300,0000. Based on this study, the friction factor for a mine opening was found to depend not only on the size and shape of the surface asperities but is also affected by the orientation of them in relation to the flow direction.

Jan 1, 1991

By M. Leduc, M. Backens, M. E. Smith

An emerging technology for sustainable development in mineral development, tailings co-disposal™ is a means to dispose of conventional mill tailings within the void space of a waste rock dump. This method, while not applicable to all tailings systems, can offer a significant reduction in short-term and long-term environmental liability, land disturbance, closure costs, and negative public image. The concept is to dispose of the tailings simultaneously with the waste rock or leach ore, controlling the ratio of tailings to coarse material such that the resulting dump is stable both physically and chemically. The resulting co-disposal dump can be as safe as a conventional waste dump. In the case of alkaline tailings in a potentially acidic waste dump, the acid production can be buffered or slowed.

Jan 1, 2004

By -Ing. Alexander Dohmen, -Ing. Gunter Hagen

In order to improve the thermal environment in deep coal mines, two principles can be applied: firstly, the reduction of heat flow into the air stream, and secondly, cooling of the air current. First of all one should try to minimize the heat-flow rate into the air stream underground by the mining method itself. German coal mines prefer the caving system of advance longwall mining simultaneously on several levels with ascensional ventilation. The effects of descensional ventilation and different face ventilation layouts on the thermal environment are discussed, besides the effects of pneumatic and hydraulic stowing. Application of all mentioned possibilities together instead of today's common mining method would reduce the Basis Effective Temperature considerably. In the future, hydraulic haulage of the raw coal underground substituting belt conveying may be a mean to improve the thermal environment further on. If the working depth of a coal mine exceeds about 1 000 m, cooling of the air stream under-ground will be necessary in addition to the above- mentioned measures. Generally, in German coal mines different types of indirect-contact air coolers located nearby the face are used. Besides such so-called cooling coils, large-capacity spray coolers are used because they work more efficiently if a great cooling duty is demanded. Common designs of both air cooler types and their possible utilizations are demonstrated. Deep coal mines in the Federal Republic of Germany need up to 30 MW of total cooling capacity. Mostly, the needed chilled water is cooled by large-capacity refrigeration plants placed on surface, underground or in combination of the above locations nearby the shaft. Due to the increasing underground cooling demand, the distribution of the chilled water and the control of the air coolers become more important. The conception of a control system is discussed, which is based on the control of the single air coolers. All air coolers of a mine are controlled so as to optimize the supply water-flow rate with regard to the demanded cooling duty of the coolers. On the next upper level of the control system the whole chilled water network and finally the refrigeration plant is regulated. Present research work deals with the use of ice for cooling mines. There are some unsolved problems in this new cooling concept. Some aspects of making, transporting and storing ice are described. The use of ice may probably reduce the cooling costs of German collieries, which are at present approximately 4 DM per ton of saleable coal.

Jan 1, 1989

By G. L. Myers

The Fortitude skarn near Battle Mountain, NV is currently one of the largest producing gold skarns in the world. It contains about 11 Mt (12 million st) of minable ore grading 5.14 g/t (0.149 oz per st) and is the distal portion of a continuous skarn system in the Copper Canyon area centered on the Eocene Copper Canyon granodiorite porphyry. Calcsilicate compositions, opaque mineralogy, and the high gold grades are atypical of other base metal skarns (iron, Fe; copper, Cu; lead-zinc, Pb-Zn; or tungsten, W). The Copper Canyon skarn is systematically zoned from a garnet (AD 70-100) dominant, pyroxene (HD 20-45) subordinate zone, with major Cu mineralization, adjacent to the intrusive (West ore body), to a pyroxene (HD20-100) dominant, garnet (AD90-100 cores. AD 30-60 rims)subordinate assemblage, with major Au, near the distal marble front (Fortitude ore body). An extensive biotite ± diopsidic pyroxene ± kspar alteration halo surrounds the pyroxene > garnet gold-bearing skarn and represents the early stages of metasomatic alteration. Retrograde alteration is limited in areal extent and intensity, and consists of actinolite, chlorite, quartz, and prehnite. Economic gold mineralization begins in the pyroxene > garnet zone and continues to the marble front, a distance of 1 to 1.5 km (0.6 to 0.9 miles), respectively, from the plutonic contact. The opaque mineralogy in this gold zone includes pyrrhotite, arsenopyrite, marcasite, minor chalcopyrite, galena, sphalerite, argentite, hessite, hedleyite, volnyskite, and native bismuth and gold. The pyrite-pyrrhotite geothermometer yields temperatures that range from 450° C to 300°C (842° F to 582° F) and the electrum-argentite-sphalerite geothermometer yields temperatures which range from 290°C (554° F) at the marble front to about 420°C (788° F) more proximal to the intrusive. Log fS2 calculations from the sulfide assemblages yield values near - 10 with log fO2 values of about -30, in a solution of near neutral pH (5-6). Calculations of metal solubility suggest that the metals were transported as chloride complexes in the proximal skarn but that bisulfide complexes were predominant within the distal gold skarn. Relatively low oxidation states buffered by the carbonaceous to argilliceous, calcareous protolith and subsequent ferrous iron-rich skarn assemblages appear to have increased the gold carrying capacity of this large hydrothermal system.

Jan 1, 1991

By G. M. Molinda

Some of the most difficult coal mine roof in the U.S. can be found in the Illinois Basin. Factors contributing to the high roof fall rate include: weak moisture-sensitive roof rock, high horizontal stress, and limited longwall mining. The depth of cover ranges from 90-1,000 ft and roof damage from horizontal stress can be severe. Moisture sensitive-roof rock is common above the Springfield-Harrisburg Herrin #5 and #6 seams in the Illinois Basin, and contributes to roof skin deterioration. The roof fall rate increases significantly in the humid summer months. The National Institute for Occupational Safety and Health (NIOSH) has shown, using lab and field studies, that highly moisture-sensitive roof rock can be directly correlated to poor roof conditions. Controlling the skin is the key to reducing rock fall injuries, and roof screening is, by far, the best remedy. Illinois Basin coal operators have been successful in reducing the number of rock fall injuries in recent years. NIOSH has documented best practices for screen installation which has resulted in safe, efficient operations. Other solutions to skin failure include: the use of denser five bolts per row patterns to reduce spans between bolts, systematic supplemental support in intersections, straps and large pans protecting operators, and air conditioning to remove moisture from the intake air.

Jan 1, 2008

By J. R. Iwinski

Escanaba, Michigan, is located on the South¬ern shore of the Upper Peninsula on a sheltered area of Lake Michigan called Little Bay de Noquet. The Chicago and North Western Transportation Company has operated a rail-to-ship ore transfer facility at this location for well over 100-years. It is the only terminal of its type on Take Michigan and thus can offer a longer navigation season to lower lake markets than other upper lake ports. It all started in 1864 when the Peninsula Railroad of Michigan, now a part of the C&NW, completed a 100 km rail line from Little Bay de Noquet to the Jackson Mines at Negnauee, Michigan. During that first year of operation approximately 31 000t of ore were loaded onto ships at Escanaba from what was then called the Merchants Dock. By 1871 demand had already exceeded capacity and it was necessary to build a larger dock, which in turn was replaced with a still larger pocket dock in 1903. There are no plans or records available to indicate how the ore was handled from rail to ship prior to the construction of the pocket dock.

Jan 1, 1981

By Jair Carlos Koppe, João Felipe C. L. Costa, Luis Eduardo de Souza

United Nations (UN) has been leading an international committee to define the guidelines in reporting resources and reserves. The system proposed by UN is very similar to the guidelines currently in use in Australia known as JORC guidelines (Joint Organisation Reserves Committee). The JORC guidelines show major differences in relation to the Brazilian system current in practice. The important aspects differing JORC from the current Brazilian guidelines for reporting reserves is the required sampling spacing. The JORC system requires the points of observation to be closer spaced than the Brazilian system for any class of resources. All classification systems share some common aspects in terms of defining the classes of resources based on distance separating samples and on the degree of confidence or accuracy associated with the results reported. Despite of being very clear in terms of stating sample distances, all the systems of classification do not provide clear definitions on how confidence limits should be calculated. This paper proposes a geostatistical framework to measure the uncertainty associated with the reported tonnages and grades. Results demonstrate that the error associated with an estimate can be approximated using multiple simulated deposits to define confidence limits. The methodology is illustrated in a large Brazilian coal deposit and proved to be appropriate to address the issue of quantifying the uncertainty necessary to be incorporated in the systems of reserves classification.

Jan 1, 2002

By B. J. Scheiner

The Bureau of Mines has developed a system for dewatering waste slurries by flocculating mineral particles with polyethylene oxide (PEO) and dewatering the resulting flocs on static and/or rotary screens. This paper discusses data obtained from dewatering, rheology, and ion-exchange experiments. A possible mechanism is postulated for the attachment of PEO to claylike particles through a water bridge with the intershell waters of the exchanged ion and the polymer.

Jan 1, 1986

By R. F. Hüttl

World-wide Germany is the leading lignite mining nation. Most of the lignite is produced in opencast operations. However, opencast mining causes enormous impacts on natural ecosystems and even on entire landscapes. The extensive production of lignite particularly in eastern Germany results in large devastated areas, which so far have been reclaimed only to some part. For the restoration of the post-mining area of more than 80,000 ha the major land use option is the reestablishment of forest ecosystems. However, adverse site conditions of the post-mining landscape such as extreme soil acidification and salt concentrations call for specific recultivation practices. Therefore, after the German reunification new reclamation and reforestation concepts have been developed for these brown coal areas of eastern Germany by the Collaborative Research Center (SFB 565) at the Brandenburg University of Technology at Cottbus (Germany). As a case study our comprehensive investigations into forest ecosystem development on terra nova in the Lusatian lignite mining district, south-east of Berlin, will be presented.

Jan 1, 2003