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By G. Shore

Radiation grafted structures my be fabricated to contain ion exchange groups selective to an ion complex. Proper choice of substrate and monomer will provide selective ion exchange with differing physico and chemical properties. Grafting a selected monomer to the proper polymer will provide selective ion exchange with assured chemical protection of the substrate. Ion exchange systems utilizing radiation grafted structures have been fabricated to ''capture'' gold, silver and palladium from dilute solutions. Other ion exchange systems can feasibly be produced to remove other precious metals. Rotating Cathode Technology is used to recover the metals from their regenerating solutions are pure metal foil.

Jan 1, 1985

By Jon G. Bredeson

The electromagnetic noise that exists in a mining environment is quite severe and was shown to have been reasonably well documented by a number of researchers in the Phase I Report. The noise levels are such that prudent communication design requires the careful use of all the electromagnetic noise data available. A comprehensive survey was undertaken to determine techniques used in various industrial environments to achieve secure communications in the presence of electromagnetic interference. The techniques were given in the Phase I Report and are rudimentary, but have produced reasonably good results. A number of these techniques could be applied to the mining environment.

Jan 1, 1980

The investigation summarized in this report addressed two primary issues: the determination and use of correction factors, and the development of guidelines for velocity measurement site selection. Other ancillary issues which were addressed include a comparison of measurement methods and devices, aircourse cross-sectional area measurement, and characteristics of mine airways. An exhaustive literature search and analysis was performed; extensive in-mine experiments were conducted; a quantitative analysis of the data was used to develop correction factor tables and site selection guidelines. The reported results of other researchers who have examined the correction factors and site selection criteria, were analyzed in light of the results of this study. The measurement devices included in the experimental phase were: vane anemometer, vortex shedding anemometer, a prototype thermoanemometer, smoke tube, and, oil of wintergreen. The measurement methods include single-point centerline, timed¬-point traverse, continuous traverse for the anemometers, and various distances and cloud positions for the smoke tube and oil of wintergreen devices.

Jan 1, 1983

By David G. Adam

Introduction Syncrude Canada Ltd. is the operating company for a consortium of industry and government participants that produce synthetic crude oil from their leases in the Athabasca Oil Sands. Production from the $2.3 billion (1978) integrated mining, extraction, and bitumen upgrading and utility complex started in September 1978. Production is currently about 6.4 Mm3/a (40 million bbl per year) of high quality synthetic crude oil. This is done by upgrading the extracted bitumen from the oil sands mined. Plans are to increase the production to 8 Mm3/a (50 million bbl pier year) by 1989. At that time, the mining operation will be required to deliver 100 Mt/a (110 million stpy) of oil sand (ore) to the extraction plants, and handle quantities of waste ranging from 50 to 75 Mt/a (55 to 83 million stpy). The Syncrude plant is located at Mildred Lake, 40 km (25 miles) north of Fort McMurray and 480 km (300 miles) north of Edmonton, Alberta. Climate, particularly winter, is therefore a major factor affecting the design and operation of all the Syncrude production facilities. Bitumen production, consisting of overburden removal, oil/sand mining, bitumen extraction, and tailings disposal, account for about half the total SCO production costs. Considerable research and development, therefore, continues to be applied to improve both material handling and bitumen recovery methods. Potential applications for feeder breakers were identified in the material handling aspects of both overburden and oil sand mining to reduce cost and to attain planned production increments. Overburden removal Overburden materials on the leases comprise thin Pleistocene sands, gravel and fill, and sands, silts and clays of the thicker Clearwater Formation with the silt to clay components predominating. The latter contains multiple leases of hard siltstone with unconfined compressive strengths up to 148 MPa and thicknesses up 0.1 to 0.9 m (1 to 3ft). Characteristics of the overburden as well as the climatic environment and scale of operation present unique problems for the efficient removal of the material. In a bucketwheel/conveyor system, the weak silty clay formations require relatively flat working slopes for safe operation, while the siltstone lenses and frozen overburden require blasting or selective removal by other equipment. These factors, combined with the normal bucketwheel/conveyor design parameters, lead to high capital investment and relatively inefficient use of that capital. Hydraulic mining alternatives, including dredging, are constrained by severe clay settling problems in the waste disposal

Jan 6, 1986

By Andrew M. Leszcykowski

This report represents the first comprehensive accounting of lode mining sites in the Sheep Mountain mining district, Custer County, Idaho. Twenty-one mine and prospect locations have been added to the Bureau's Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of a mineral appraisal of the River of No Return Wilderness; previously known locations were checked and the updated information added to the data base. The district's deposits are mainly confined to metasedimentary xenoliths in granodiorite and quartz monzonite. Those deposits in the north and west parts of the district are lead-silver-zinc replacement veins in dominantly calcareous facies; those in the southern part of the district are polymetallic fissure-veins containing pyrite, chalcopyrite, arsenopyrite, galena, and sphalerite hosted by micaceous schist and phyllite. The dominant structural trend in the southern part of the district is northwesterly and on strike with major deposits in the adjacent Seafoam mining district.

Jan 1, 1983

By Walter W. Kaufman

This report summarizes a study conducted to determine the state of the art of various rock removal systems and their capabilities. The objective of the study was to determine if currently manufactured equipment can adequately accomplish rock removal in surface mine reclamation applications. Evaluations of state reclamation regulations, with regard to topsoil rock content, were made to determine the rock removal requirements. The major categories of equipment studied are rock pickers and rock rakes. The impact of rock removal implementation on the reclamation operations is discussed in detail.

Jan 1, 1979

By Roy Jennings

The Discovery Expedition of St. Charles, MO chose to build its two-story museum in the flood plain of the Missouri River, near the starting point of the Lewis and Clark Expedition. Should the lower level be inundated at flood stage, plans call for the replica riverboats to be moved by trailer to higher ground. The museum's design required an open span structure with heavily loaded footing or piles. Spread footings could not be used due to the compressible soil profile. The location, in a historical district, precluded dynamically driven piles. Sixty-three uncased Helical Pulldown Micropiles were driven to the bearing stratum to support the museum with minimum disturbance. There were no spoils to dispose of during construction and the piles were completed in eight working days with minimum impact to the environment and neighborhood. The maximum working load required was 84,000 pounds (374kN). Test results are given in the form of installing torque.

Jan 1, 2003

By W. P. Johnstone

The computer assisted generation of geological models to represent the geometry of, and grade distribution within, orebodies is a rapidly growing area of the geological profession. Such models are increasingly used as a necessary starting point in determining the mineability of mineral deposits in terms of practical mine design and economic considerations. The transition from traditional techniques such as field or underground mapping and the manual calculation of grade and tonnage estimates, as well as related activities such as the interpolation of cross-sections, the use of stereographic projections, core logging and hand contouring, to computerized applications, is by no means complete. In fact, many geological professionals deliberately avoid the use of computer simulations based on the perception that the resulting models are simplistic and that their construction is not founded on sound geological principles. The purpose of this paper is to assess current thinking on this topic by considering; (a) an overview of advances in the drafting of geological maps, (b) the theoretical basis for multi-dimensional geological modelling, (c) the case for combining traditional and modern techniques, and (d) the benefits to the mining value chain.

Jan 1, 2003

By R. P. Goel, P. N. Chaudhary, R. K. Minj

The bulk of high carbon ferromanganese produced in India continue to have more than 0.35% phosphorus since they are produced by carbothermic reduction process. The low phosphorus manganese ores are depleting fast and ferromanganese manufacturers will have no option but to use medium and low grade ores having high phosphorus content resulting in high phosphorus in the product. A systematic study was taken up at NML to solve this problem. Initially, a thermodynamic analysis was carried out for which Ba-P-O ternary predominance diagrams were constructed at several temperatures to predict the most suitable conditions for selective removal of phosphorus from high carbon ferromanganese. These conditions required a usage of a flux having a high level of basicity, moderate oxygen potential as well as low melting temperature. The experimental results showed that it was possible to remove phosphorus from high carbon liquid ferromanganese from 0.56%to 0.18% using BaCO3 based fluxes at the rate of 16-wt% of the ferromanganese charged. However, the Mn loss varied in the range of 2-5%. The objective of the subsequent study carried out at the laboratory scale was to optimize the flux consumption as well as minimize the Mn loss with effective dephosphorization by using BaO based calcined pellets instead of BaCO3 based powders. It was felt that the handling of pellets under plant conditions would be easier and also eliminate the loss of flux as a dust, which occurs when powder is added. These pellets were forced towards the bottom of the melt for better efficiency. For this purpose, a plunging system was designed and fabricated in-house that helped in reducing the flux consumption to less than 5% and also improved the kinetics of the process. The desired results were achieved within 10 minutes of the addition of the flux. The know-how is ready for transfer to interested parties and authors are willing to conduct large scale trials with them.

Jan 1, 2007

By Henri F. Letient

At the 25th Annual B.C. Mine Reclamation Symposium in September 2001, Huckleberry Mines Limited received the Jake MacDonald Reclamation Award for its exemplary mine waste management plan, conceived to prevent the onset of acid mine drainage and facilitate reclamation of the site. The mine is an excellent example of a total mine waste management plan, with all materials scheduled in detail for the life of the mine. The filling plan for the waste management facility takes into consideration the requirement for permanently flooding the potentially acid generating rock. From an acid generation point of view, the tailings fall in the zone of potentially acid generating material. To avoid long-term ARD concerns, it is planned to float pyrite out of the tailings towards the end of the mine life, thereby generating a non-acid generating tailings stream which will be used to cap the deposited mine waste. The pyrite-rich tailings will be discharged into the deeper portion of the impoundment. On closure, a permanent water cover will be maintained over the mine waste. Only beaches of non-acid generating tailings will remain exposed. Mining will be phased to also allow one of the pits to provide storage for potentially acid generating rock and to be flooded at the end of mine life.

May 1, 2002

By Michel Aubertin

Les haldes à stériles contenant des minéraux sulfureux réactifs constituent un milieu favorable à la production du drainage minier acide (DMA). Au sein de ces haldes, les processus physiques, géochimiques et biologiques qui mènent à la production du DMA sont nombreux et complexes. Un des aspects critiques qui affecte la génération de DMA est la distribution et le mouvement de l?eau dans les roches stériles. La modélisation numérique est un outil qui permet de comprendre, pour éventuellement contrôler, les mouvements de l?eau (et donc réduire la production du DMA) dans les haldes pendant la période d?exploitation de la mine et à sa fermeture. Plusieurs simulations numériques des écoulements non saturés dans des haldes ont été effectuées. Pour ces simulations, on a considéré divers types de matériaux, diverses conditions atmosphériques et diverses configurations géométriques. Les simulations réalisées montrent que l?on peut contrôler les mouvements de l?eau en introduisant des couches de matériaux fins intercalées dans les haldes formées de matériaux grossiers. Des couches horizontales ne sont cependant pas appropriées puisqu?elles peuvent, dans certains cas, favoriser la création de zones humides susceptibles d?amplifier les effets du DMA. Une faible inclinaison des couches de matériaux fins vers l?extérieur permet de palier à ce problème. Les couches inclinées favorisent un drainage des haldes vers la périphérie. Ceci a pour effet de garder sèche une grande partie des stériles et de réduire, par le fait même, la production du DMA.

Nov 1, 2002

By Thomas J. Peters

Tungsten, silver, lead, zinc, and placer gold occur in the Cucamonga B RARE II area (no. B5174). A strata-bound, scheelite-bearing zone at the Blue Diamond prospect (fig. 1, no. 1) contains an estimated 16,000 tons (15,000 t) of identified, subeconomic resources averaging 0.16 percent tungsten trioxide (W03). There is a high potential for discovering additional tungsten resources at this property. The California-Hercules prospect (fig. 1, no. 5) ha; a mineral occurrence which contains an estimated 1,000 tons (900 t) of tactite averaging 1.3 oz silver per ton (45 g/t), 0.75 percent lead, and 0.72 percent zinc. Another occurrence, at the Blew Jordam Prospect (fig. 1, no. 4) has an estimated 100 tons (90 t) of tactite averaging 10 oz silver per ton (340 ,/t), 3.75 percent zinc, and 2.3 percent lead. There is a moderate potential for discovering silver, lead, and zinc resources at these prospects, which are in metamorphic pendants. There are a few lode gold prospects in the area (fig. 1, nos. 3, 11, 14) are on geologic structures which parallel the San Andreas Fault, northeast of the area. These deposits are not well exposed and have been historically unproductive. Placer gold in area B occurs locally in the beds of intermittent tributaries to Lytle Creek (fig. 1, nos. 10, 12, 13) in concentrations as high as $1.17 per cu yd ($1.53/cu m, at a gold price of $450 per troy oz). The deposits have no significant volume, but could be utilized for recreational panning and suction dredging. In the Cucamonga C RARE II area (No. C5174) placer gold occurrences locally contain as much as $1.23 per cu yd ($1.61/cu m). However, gravel containing the gold appears to be limited to stream beds, and does not occur in sufficient quantity to constitute resources. Recreational panning and dredging also may occur in this area.

Jan 1, 1983

By Douglas Bartley, Brian Wingfield, Robert McClure

Recent studies and limited tests indicate favorable results utilizing high accuracy electronic detonator technology over conventional non-electric pyrotechnic systems. This study discusses the application of this technology using the Daveytronic programmable system in an on-going production basis. The study quantifies the performance as it relates to fragmentation, excavation, vibration and productivity in an eastern U.S. aggregate mining operation.

Jan 1, 2001

By Jack Eloranta

"This paper compares energy requirements for blasting, crushing and grinding. By tracking electricalconsumption for various powder factors, a general trend has appeared. This study involved over 100million tons of ore and powder factors ranging from .5 lbs/L,T to .8 lb&T. Actual energy usage iscompared to predicted energy based on the Bond equation."

Jan 1, 1998

By F. F. von Glehn

There is no doubt that simulated ventilation networks must be adequately verified before they can be extrapolated and used for predictive purposes. There are two general approaches as to how the verification can be established and these are summarised as follows; The first approach is to measure all individual branches with trailing hoses or barometers to get individual pressure drop and flow per branch and then calculate individual resistance factors for input into the software. The simulator is run, checking that the output makes general sense (check some sensitivities if possible). The network is now considered as verified. The pressure drop to be measured is relatively small and thus it is inherent that the measured set of individual K factors will be imprecise no matter how much care is taken in the measurements and the resultant simulations will inherit the same problem. In the second approach, the network is assembled using estimated (Atkinson) K factors (based on physical features of airway, past experience and catalogued typical K factors). Only the main primary flow rates are measured and hence the relative distribution of the primary ventilation in the main airways is determined (probably about 10 off primary air flow measurements). Main critical pressure differentials at main and booster fans and across critical doors are measured (probably about 6 off primary pressure differential measurements need to be made). The simulator is run and the computer model is used to iterate and select an updated suite of K factors so that the flow balances and pressure differentials are correctly simulated (typically only 2 or 3 iterations are all that is needed). The network is now considered as verified. The pressure differences to be measured will be substantial in absolute terms and can be measured with high precision. Also, because only primary flows are measured, these will generally be measured at higher air speed points and hence improved relative accuracy. This leads to more accurate simulation results. This paper examines the advantages and disadvantages of the two approaches. 1 Background

Jan 1, 2009

By C. Pelley, S. Kelebek, T. Katsabanis, B. Nanthakumar

"As part of a larger investigation on generation of fines from mining activities and their effect on downstream operations, ore samples from Onaping area stockpiles of Falconbridge Ltd were studied. Batch flotation tests were conducted on the stockpile samples and fresh ore samples to explore the effect of stockpiling on grade-recovery performance. Head grade and particle size distribution of the samples from stockpiles were adjusted so that the samples compared are similar to each other. In additional tests, fresh ore samples were blended with stockpile samples at various percentages, representing 27.4, 50.2 and 81.5% of stockpile samples.The samples from stockpiles produced inferior nickel grade-recovery curves compared to fresh ore. The poorer grade-recovery performance was attributable to two factors. First, a significant dilution effect was observed due to the nearly complete flotation of pyrrhotite. Secondly, while pyrrhotite from stockpiled ore became highly floatable, the same stockpiling conditions caused nickel losses that were attributable to non-floatability of some pentlandite.In the case of blending, there was generally insignificant difference in the nickel grade-recovery between fresh and blended samples when the blending cases involved 27.4 and 50.2% stockpile samples. However, an increase in pyrrhotite recovery was observed for both blending cases. At 81.5% blending case, degraded grade-recovery was significant primarily due to the nearly complete flotation of pyrrhotite. There was a small, but noticeable amount of nickel loss for this case. However, for lower ratios of blending this loss was negligible.The increase in pyrrhotite recovery was partly attributed to its activation by Cu and Ni ions. Formation of a significant amount of elemental sulphur was also apparent from analysis of stockpiled samples. It can be concluded that pyrrhotite is mildly oxidized under stockpiling conditions while part of the pentlandite undergoes a more severe oxidation."

Jan 1, 2006

Drill blasting is a widely used method for rock fragmentation in mining, quarrying and construction industries. Environmental effects such as air shocks, dust, flying rocks and ground vibration are unavoidable results and undesired effects of blasting. Among these ground vibrations can have a damaging effect and may influence on long distances. Therefore various researchers have developed mathematical models to predict ground vibration after blasting. These models take into account the amount of explosive, distance and several coefficients related to the field under investigation. The developed models to predict ground vibration may yield different results for the same case. Selection of the most suitable model requires engineering judgment and evaluation of models. At this point, a computerised system helps the engineer to evaluate and select the most suitable model in order to design and plan a blasting pattern. The safe charge of explosive and magnitude of vibration after blasting should be predicted beforehand. Therefore a computer program namely 'prediction of blast induced vibration' (P-BIV) has been developed. This paper introduces and presents a computer program (P-BIV) which includes the set of models developed to estimate ground vibration to provide blasting engineers a tool to determine the amount of explosive for safe blasting.

Dec 6, 2010

By Emmanuel N. Zevgolis

Energy required for roasting and smelting of a nickeliferous laterite ore by the rotary kiln - electric furnace process is investigated. From this work it comes that thermal energy is about 65% of the total energy needed and the rest is electrical. Also, 61.3% of thermal energy input in the roasting step (of all combustibles fed into the rotary kilns) is used for pre - heating, 11.6% for pre - reduction and the rest (27.1%) corresponds to the energy of the remaining carbon in the rotary kiln products (i.e., calcine, dust and coatings). Carbon entering the system is used as follows: 57.9% for combustion, 37.1% for reduction and the rest (5.0%) remains unburnt. Exploitation of energy from gases of both furnaces, as well as the higher possible reduction degree, the optimum temperature of the calcine and also elimination of the excess air in the rotary kilns, improve significantly energy balance and economics of the process.

Jan 1, 2006

By Jon C. Volkwein

In This Chapter [Instruments for measuring dust How to calculate the amount of dust from a source How to get a valid concentration measurement Sampling to assess control technology effectiveness] When there is more than one source of dust, sampling may be required to find which dust sources are most significant. Then, efforts to reduce dust can be concentrated where they will have the most impact. This chapter explains how to perform dust source sampling. It describes two kinds of instruments that are available and discusses their limitations. It explains how environmental variables such as concentration gradients, dust dilution, and production changes can impact dust measurements. It also suggests practical ways to improve the validity of dust source measurements under adverse conditions, such as high-velocity airflow or the presence of water mist in the air. [Dust source sampling at coal mine longwalls and at tunnels is more complicated. Chapters 3 and 7 have more information on sampling in those circumstances.] TWO KINDS OF INSTRUMENTS FOR MEASURING DUST Gravimetric samplers. The conventional gravimetric sampler is a good device for measuring dust because it is the instrument used for compliance measurements. This dust sampler consists of an air pump, a small cyclone that separates out the respirable size fraction of the dust cloud, and a filter to collect the respirable dust. In coal mines, the Mine Safety and Health Administration (MSHA)-approved gravimetric sampler uses a 10-mm Dorr-Oliver cyclone operating at an airflow of 2.0 L/min [30 CFR78 74 (2002)]. A correction factor of 1.38 is applied to make the results consistent with the U.K. MRE sampler, the instrument on which the 2.0 mg/m3 coal dust standard is based.

Jan 6, 2003

By H. B. Arntzen, P. O. Grøntvedt, T. Lindstad, R. J. Ishak, M. Syvertsen

Better utilisation of electric power and coke is vital in reducing production costs and CO2-emissions in production of ferromanganese. All FeMn smelting operations consume 10 to 30 % more carbon than the carbon needed to reduce MnO and FeO to metal and the carbon contained in the alloy. Potassium which re-circulates and builds up in the furnace has been shown to be the main culprit causing both excessive carbon consumption, by catalysing the Boudouard reaction, and increased electric power consumption. The reaction between CO2 and ordinary metallurgical coke or coke impregnated with potassium has been studied at temperatures from 800 to 1100°C in a thermobalance apparatus. Ordinary coke did not react to any great extent at temperatures up to 1000°C, whereas the addition of potassium (2-10 %) resulted in a huge increase in reaction rates. The ultimate goal is to fit the results into a reaction rate model containing the equilibrium constant for the solid-gas heterogeneous reaction between CO2 and a free active site on the carbon reactant producing CO and adsorbed oxygen (an occupied site). The model includes the partial pressures of CO and CO2, a reaction rate constant that is a function of both the total number of reaction sites of carbon, and the potassium content. The potassium dependency is taken care of by introducing activity coefficients for the carbon sites. As the first step towards such a model, a regression line for the Boudouard reaction rate has been established.

Jan 1, 2004