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By F. Figge, T. Hahn

In this article we present Sustainable Value, a valuation methodology to assess sustainable value creation of companies. Sustainable Development posits that decisions must not only take into account economic capital but also natural and social capital. Sustainable Value, the methodology presented in this paper, borrows the idea from financial economics that the return on capital has to cover the cost of the capital. Capital costs are determined as opportunity costs, i.e. the forgone return that would have been created by an alternative investment. By expanding the well established logic of the valuation of economic capital in financial markets to also cover natural and social capital we provide a methodology that allows an assessment of the most efficient allocation of economic, natural, and social capital for sustainable value creation in companies. We demonstrate the practicability of the methodology by the valuation of the sustainability performance of British Petroleum (BP).

Jan 1, 2005

By B. Das, B. K. Mohapatra, K. S. Narasimhan, S. K. Bhaumik

The iron ore slimes (d80 ~ 50 µm) generated at Noamundi iron ore washing plant (TISCO), assaying 57% Fe, 4% Si02 and 8.3% A1203, have been subjected to hydrocyclone studies. The effects of different design and operating parameters have been studied to get a product suitable for subsequent use in the sinter mix. The studies indicate that it is possible to obtain a product containing 64% Fe, 1.4% Si02 and 3.5% A1203 with a recovery of 49% iron. The process involves classification followed by separation in a hydrocyclone. By this method, the overall yield of iron ore production in the plant is expected to increase by 8%. Microscopic examinations and X-ray diffraction studies were conducted to elucidate the mineralogy and liberation characteristics of Noamundi iron ore slimes. This paper deals with the findings of the investigations.

Jan 1, 1993

By Jack Bradbury

The open stope room and pillar method of mining is used throughout Ozark Lead Company's underground mine located at Sweetwater, Missouri. This method of mining produces an approximate overall ore extraction of 80%. Pillar recovery, on a limited and experimental basis, was started in January of 1979 to determine the maximum size underground opening that could be mined safely. Monitoring the roof and surrounding pillars for potential failure during this pillar recovery process was accomplished by utilizing a simple rod extensometer to measure roof sag. Boreholes 7.5cm in diameter were drilled 3.5m into the roof to spot any separations or cracks that might have propagated between the bedded layers of rock. Underground openings 85m in length by 46m in width have been mined successfully without roof or surrounding pillar failure. Continued measurements to establish long term results will be necessary.

Jan 1, 1981

By V. Saltas

The present work investigates whether dielectric spectroscopy can be used to detect contamination, which may appear in a natural porous material, due to the spreading of pollution. For this purpose, dielectric and conductivity measurements, in the frequency range of 10mHz to 1MHz, were carried out in sandstone samples, partially filled or saturated with solutions of leachates, at different concentrations. The experimental results suggest that although the role of water is dominant to the measured electrical conductivity, variations of two orders of magnitude are observed due to the different concentrations of leachates, in partially filled sandstone samples. Experimental data are well fitted with a Havriliak?Negami dielectric relaxation function, superimposed with a conductivity term. The parameters of the fitting function have been correlated to the concentration of leachate in the sandstone samples and considerable changes have been observed at low leachate?s concentration.

Jan 1, 2005

By V. Avdiyskiy

The most pressing topic raised nowadays by the world community faces environment and social consequences of the business intensification process, primarily that of mining and mineral industry, which is through the number of its activities mostly associated with pernicious impacts. World top managers are confronted with the dilemma of reconciling traditional financial framework aiming at successful business development measured by revenues, shareholder value, profit margin and incorporating Sustainable Development (SD) at all levels of decision making process, avoiding depriving future generations of the means to meet their own needs. The rapid consolidation and globalization of the industry stipulates that companies are an integral part of the world economic environment. Therefore a company?s financial performance is under the pressure of operational and environmental performance. Among them special attention is paid to the social and economic background, the relationship with regulatory institutions, and the developments for environmental protection.

Jan 1, 2003

By M. H. Foroughi

This paper discusses the effects of seam inclination and lateral stresses on the stress distribution in pillars in inclined coal seams. The average pillar stress is a function of the overburden weight, the mine depth, the effective extraction ratio and the angle of seam inclination. Normal and shear stresses in the pillar are computed by numerical modeling. In medium dipping seams, leaving a pillar with its axis normal to the stratification causes a shearing stress concentration in the top and bottom corners of the pillar. This results in the pillar possibly becoming less stable in comparison to pillars in horizontal coal seams. Therefore, to reduce the stresses, it may be necessary to leave the pillar at an angle of b deviated from the normal axis to stratification. A mathematically approximate formula for determining b is proposed, and the results are confirmed by numerical modeling.

Jan 1, 1998

By G. G. O. O. Uwadiale, M. A. U. Nwoke

The flotation of Azara barite tailings was investigated using crude rubber nut oil (RNOc), refined rubber nut oil (RNOR) and oleic acid as fatty acid collectors. Chemical characterization of the rubber nut oils indicated high acidity, high saponification values and high iodine indexes, which are indicative of a high fatty acid compositions. The Azara barite tailings analyzed 64.6% BaSO4 by atomic absorption spectrophotometry. Gravity and magnetic separation techniques yielded a BaSO4 concentrate with a grade of 74.8% and a recovery of 92.5%. Barium sulfate grades of 90.0%, 92.8% and 94.8% with recoveries of 80.3%, 85.4% and 86.7% were achieved with collector dosages of 750g/t crude rubber nut oils, refined rubber nut oils and oleic acid, respectively. Hence, rubber nut oils are effective fatty acid collectors for the flotation of barite tailings.

Jan 1, 1998

By C. A. Wiggins, J. M. Kennedy

The Benbrook Connection tunnel forms approximately 6,666 m (19,560 ft) of17,678 m (58,000 ft) of raw water pipeline connecting Lake Benbrook with the Rolling Hills Water Treatment Plant. This connection is designed to minimize costs to the owners, the Tarrant Regional Water District, for providing raw water to its’ various clients. The geological formations through which the tunnel passes and the design requirements resulted in some-what unique applications of initial ground support systems which were modified by the con-tractor to optimize the mining operations. The pipe sections, fabricated in 12 m (40 ft) sections, are concrete lined and coated steel pipe. Construction of the work shaft and tail tunnel was also modified to suit the contractors methods. A Lovat universal TBM was chosen to excavate through the various rock types. The pipe sections will be transported using beam carriers.

Jan 1, 1997

By Shahzad Moosa, John M. Pitt

Statistical variability in rock strength can be evaluated by rapid, inexpensive ultrasonic pulse velocity measurements, an important consideration since rational probabilistic design in rock is often hampered by the cost of obtaining sufficient strength data. Experimental ultrasonic pulse velocity measurements on a set of 96 limestone specimens showed two distinct statistical populations. Both populations followed Weibull distributions, with flexural strength distributions paralleling pulse velocity distributions. Thus, experimental results suggest that strength variability may be predicted from a few rationally selected strength measurements and several ultrasonic tests. The correspondence between strength and velocity may then be used to develop an experimental transformation function, allowing the development of a statistical distribution function for strength based on the known statistics of velocity. Comparison of experimental groups with full sets of corresponding strength1 velocity data showed the technique offers a fairly accurate description of the statistics of strength.

Jan 1, 1986

By Chris Mark

In the wake of the Crandall Canyon mine disaster, the U.S. Congress asked the National Institute for Occupational Health and Safety (NIOSH) to study the safety of deep cover pillar recovery operations in the US. The legislation defined ?deep cover? to be greater than 1,500 ft, but NIOSH is also evaluating mines at depths greater than 1,000 ft when multiple seam interactions are encountered. By these definitions, there about 35 active mines that engage in deep cover pillar recovery, in the states of UT, CO, VA, WV, and KY. To date, NIOSH has documented ground conditions and ground control experience at nearly all of them. This paper provides an overview of current deep cover pillar recovery practice. Specific ground control issues that are discussed include: Pillar and barrier pillar design, ? Coal bumps, Thick seam pillar extraction, and ? Multiple seam interactions.? INTRODUCTI

Jan 1, 2009

By A. A. Kornyshev, M. Burstein, S. T. Hall

The surface "roughness" of mineral particles has long been known to influence the fundamental process of particle-bubble attachment and other subprocesses in froth flotation. The physical nature of the surface of fine mineral particles can be analysed by determining their fractal geometry. A number of techniques are available to measure the fractal properties of mineral particles, these include gas adsorption, mercury porosimetry, neutron or X- ray scattering and image analysis. From the resultant Richardson plots or their Fourier-space analogs, the fractal dimension of flotation feed and product samples can be determined. Textural characteristics of particles have an influence on the stability of 3-phase flotation froths and the selectivity of recovery in the froth. Decrease of the equilibrium froth height for particles of higher fractal dimensions was experimentally established. The induction time of quartz particles of different fractal geometry has also been studied.

Jan 1, 1995

By R. Vergunst, E. A. Devuyst, G. Robbins

By the middle of 1989 Inco will have applied its patented cyanide removal technology to seventeen commercial operations. Removal of cyanide from CIL slurry tailings is applied at Equity Silver and Inco's new 1.200 mtpd mill at Inco/Golden Knight. Detoxification of CIP tailings is carried out by Colosseum California (3.600 mtpd), Canamax's Ketza River (360 mtpd) and Westmin's Silbak Premier (2000 tpd) operations. Repulped tailings from Merrill-Crowe flowsheets are treated at Total Erikson's Mount Skukum (300 mtpd) and Skyline's Johnny Mountain (200 mtpd) mills and barren bleed at Inco/Queenston's McBean mill (500 mtpd). Lynngold's MacLellan mill (1800 mtpd) and ERG (40.000 mtpd) treat pond supernatant water. Plating shop cyanide effluents are decyanized at Kuntz Electroplating and two other plating shops in Ontario. Details regarding some of the above operations are given. Operating and capital cost estimates for various treatment options are discussed.

Jan 1, 1989

By Frank K. Mattson

The Minerals Processing Section of Surface Combustion is currently engineering and erecting a plant designed to produce 400,000 LTPY of 95% metalized pellets from raw magnetite concentrate, This venture is the first domestic commercial facility that will manufacture pre-reduced pellets as an integral part of a process to produce steel. Surface Combustion has developed the methods that will be used. Midrex, a division of Surface Combustion's parent company, Midland-Ross, will own and operate this plant. The site is adjacent to the City of Portland, Oregon on a 15 acre hydraulically-filled area on the east bank of the Willamette River. Either filter cake or concentrates in slurry form will be purchased from Marcona in Peru, delivered to the dock facility by ocean vessels and distributed to a pond for wet storage. Reclamation from the pond will be with a conventional dredge delivering concentrate to a thickener.

Jan 1, 1968

By Paul D. Kovscek, Charles D. Taylor, Edward D. Thimons

When blowing ventilation is used on a mining section, a machine-mounted scrubber is often required to maintain face dust levels below 2 mg/m3. Operation of the scrubber also affects airflow patterns at the face and the dilution of liberated methane. Reductions in scrubber flow can result in increased methane concentrations. During mining, loading of the scrubber filter with dust is likely to reduce airflow. Detecting changes in scrubber flow is difficult, especially with extended cutting, because the machine must be operated from a remote location. Tests were conducted to demonstrate how scrubber airflow could be continuously monitored at a remote location. Three variables, static pressure at the fan inlet, differential pressure across the scrubber filter, and scrubber fan motor current, were continuously monitored while the scrubber filter was incrementally loaded to reduce air flow. The results show that monitoring each variable provided a way for estimating scrubber flow.

Jan 1, 1995

By P. C. Thakur

The history of coal mining in the United States of America and the rest of the world is replete with mine explosions and consequent loss of lives. Serious efforts in the USA to recover methane prior to mining and post mining started about forty years ago. CONSOL Energy Inc. and government agencies, e.g., the erstwhile US Bureau of Mines developed several techniques of methane drainage, such as in-mine horizontal drilling, vertical gob wells, hydrofracing of vertical wells and horizontal drilling from surface. With the current technology, thirty to sixty percent of total methane emissions from a mine can be captured making the mines much safer and more productive. Drained methane is often marketed to defray the cost of methane drainage. This paper is an anthology of these developments and describes how coalbed methane, which used to be a bane, has become a boon for the coalmining industry.

Jan 1, 2003

By S. R. Abt, J. D. Nelson, G. M. Smith

An empirical investigation was conducted to formulate a design criteria for predicting the beach profile of hydraulically deposited tailings. Field data were obtained from mining operations producing gold sulfides, silver, molybdenum, copper, platinum, and uranium. Site-specific parameters were collected that included the beach slopes, tailings soil properties, slurry properties, and the slurry distribution system characteristics. Each of the beach profiles were dimensionlessly plotted, and regression expressions were computed. It was determined that either a power expression or exponential expression closely predicted each beach slope. A general power expression and a general exponential ex¬pression were developed resulting in a design criteria. A procedure was formulated to determine which expression, power or exponential, is applicable to any specific site. A slope designation chart was developed as a function of the discharge, the tailings critical tractive shear stress, and the inertial forces exerted by the slurry on the beach.

Jan 1, 1987

By J. Cassells, N. Chrisman, R. Arnold, P. Rusin, L. Quintana

Toxic substances in On solutions can retard biological leaching of sulfide dump ores. On solutions were ana1yzed for metals, organics and chloride and showed inhibitory concentrations of aluminum, manganese and chloride. Inhibition of bacterial activity by the solid fraction of On solution with and without the organic constituents, was evaluated. Bacterial toxicity was evaluated by monitoring bacterial numbers, pH, Eh, and rates of iron oxidation. The On solution solids were toxic at 50% to 60% of their field concentration. Most of the toxicity of the On solution was due to the organic fraction. Different solvent extraction (SX) reagents show varying degrees of inhibition of T. ferrooxidans. Bacterial inhibitory effects of carriers and lixiviants used in the SX plant should be determined so that entrained SX reagents do not retard biological dump leach systems. The reagents used should be the most cost-effective and the least toxic.

Jan 1, 1996

By Nathaniel Arbiter

The increasing size of flotation cells as the use of flotation has increased is traced from the first United States application of the process in Montana in 1911 through the following eight decades, using data from the Taggart handbooks (1927) and (1945), from the SME Handbook (1984), and from recent manufacturers' catalogues and other sources for the 1980s and 1990s. With the earliest mechanical cells less than 1 m3 (359) in volume and the largest now available at 200 m3 (7,000ft3), three requirements are necessary: 1) demonstration of advantages in replacing smaller volume by larger volume cells; 2) estimating power requirements, impeller dimensions, and operating rpm by correlation equations; 3) considering effects of using larger cells, in necessarily much shorter rows, on process kinetics. The resulting seven tables that address these problems are presented, and their implications discussed.

Jan 1, 1999

By J. David Lowell

The discovery of the Kalamazoo (Arizona) ore body was a comedy of errors and coincidences and luck -as most discoveries probably are. The story began in early 1965 when Quintana Petroleum decided to diversify from petroleum into minerals and decided to do this by the route of minerals exploration. Quintana Petroleum is owned by the Cullen family of Houston and has Geen successful over the years in discovering oilfields. In 1965, the president and general manager was Corbin J. Robertson, son-in-law of Harry Cullen, founder of the company and a famous Texas wildcatter. But, in 1965, Quintana's financial advisors suggested that the company go into several mineral commodities, including copper, with Tucson, AZ, as the jumping-off point for copper exploration, and with a geological consultant (me) as the point man. The stage was now set! (See Fig. 1, location map of the San Manuel District, Arizona.)

Jan 1, 1991

By R. P. Killmeyer, W. W. Wen, B. K. Parekh

A continuous pilot-scale test of the GranuFlow Process was conducted using a screen-bowl centrifuge for the dewatering and reconstitution of column -flotation concentrate at a coal preparation plant in Virginia. In this test, a slipstream of the fine clean-coal slurry from the column flotation con¬centrate was treated with a bitumen emulsion before dewatering. The treated products from the screen-bowl centrifuge appeared to be dry and in a free flowing granularform, while the untreated products were wet, sticky and difficult to handle. Test results indicated that the average moisture contents of the dewatered coal products were 35.7%, 35.5%, 32.6%, 29.9% and 26.5% (by weight) with Orimulsion additions of 0.0%, 0.7%, 3.2%, 4.8% and 6.4% (by weight), respectively. The handleability and dust reduction of the dewatered coal products were also vastly improved.

Jan 1, 2000