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By Shallesh K. Patel, Richard M. Powers, Patrick Zhang

Perceived environmental impacts from flotation reagents used in the phosphate industry have been of concern for nearly a decade. A research program was initiated to determine the distribution, fate, and consequences of flotation reagents (fatty acids, fuel oils, and amines) within the environment. Therefore, laboratory investigations of biodegradation and soil attenuation of the reagents were conducted along with field flotation mass balances and groundwater investigations in clay settling, sand tailings, and undisturbed areas. Sample analysis and a reagent mass-balance model indicated that most reagents are distributed in clay settling and sand tailings areas. Groundwater analyses showed no fatty acids or amines in any of 19 surficial or intermediate aquifer water samples. In contrast, fuel oils were detected in the surficial aquifer at all sand tailings areas in concentrations ranging between 8.5 and 0.5 mg/L. Fuel oil was also detected in trace amounts (0.6 mg/L) in one intermediate aquifer well located in an active sand tailings area. All fuel oil concentrations detected were very low and, coupled with a biodegradation rate of approximately 10% per month, all concentrations should be within reference levels in six months. Based upon the results of this study, use of flotation reagents in the beneficiation process of the Florida phosphate industry present no long-term threat to the environment.

Jan 1, 1999

By G. T. Lineberry, B. R. Yama

Artificial intelligence research has produced several tools for commercial application. Some of the techniques that are widely used today include neural networks, fuzzy logic and expert systems. Artificial neural networks (ANNs) are excellent predictive, pattern recognition and data analysis tools. In the mining industry, ANN techniques are being used commercially for real-time process-control applications. Modeling of spatial data, ore-reserve estimation, tunnel design, long wall-stability prediction and geologic roof classification are additional applications in which neural networks have been applied successfully. In this study, a standard back propagation algorithm was used to train a series of neural networks for a real-world predictive task. After training and optimizing the neural network architecture, the performance of the network is measured on an independent validation set. Results indicate a mean error of less than 1 % between the actual and predicted values. A neural network model was developed for learning the spatial continuity of a mineral field and, consequently, for predicting sulfur values for given coordinates. The neural network not only performed satisfactorily, but in some cases performed even better than the kriging model.

Jan 1, 2000

By C. T. Twort

As technology and economic conditions allow mines to operate at ever greater depths, increasing demands are placed on the environmental engineer to adjust the capacity of the installed mine . - refrigeration systems. At the same time the engineer must satisfy the changing legislation, which demands that developments are carried out in as an energy efficient and environmentally accept- able manner. Following the trends outlined above, this paper is written to give an overview of the current and potential future refrigeration technology available to the mining industry. The effects that may be produced by the adoption in mining applications of the new generation of 'green' refrigerants are examined both at the design stage and when considering the viability of retrofitting existing systems so that they comply with the Montreal Protocol. An introduction to the concept of Total Energy Warming Impact (TEWI) is provided, with an explanation of its use in optimising system design and performance, and its incorporation as part of an environmental audit strategy. The paper concludes with a discussion of innovative refrigeration techniques and the possible future developments in legislation.

Jan 1, 1997

By S. C. Lamey, P. A. Hesbach

This study evaluated the use of regionally produced coal combustion products to neutralize and remove metals from acid mine drainage (AMD). Synthetic AMD mixtures were treated with a number of fly ashes and fluidized bed combustion (FBC) ashes. All of the ashes reduced the volume of the sludge produced and gave a faster settling rate than the sludge produced by treatment with lime. Faster settling allows greater throughput rates. In addition, the FBC ashes, which generally contain alkaline components used for sulfur capture, completely neutralized the acidity and, if desired, raised the pH above 10. The fly ashes, on the other hand, reduced the final volume of sludge but required additional neutralizing agents to attain a pH >5. The pH of the AMD can be taken to above 10 to insure complete removal of manganese, or it can be taken to a more neutral pH of 7 or 8 to allow for the safe introduction of the aqueous phase into ponds or streams. The process combines two industrial waste products to reduce the disposal volume of one of the waste products and to produce an environmentally safe aqueous discharge.

Jan 1, 2002

By Rajiv Hadkar, M. D. McKinley, J. B. Hiskey, B. J. Scheiner, G. W. Warren

Flyash from municipal solid waste incinerators containing roughly 13 to 15% Zn, 2% Pb and 0.2% Cd is an attractive material for simultaneous metal recovery and detoxification. Results have shown that Pb in flyash is present as PbSO4 and PbC12 and that about 70% of the Zn is present in the form of soluble amorphous compounds. Leaching results in a number of acid and basic lixiviants show that acid leaching is clearly more effective than basic leaching which is limited by low solubility of Cd and Zn. Cementation in acid solution with pH < 1 promotes redissolution of the precipitated metal. Successful zinc electrowinning from chloride leaching solutions has also been demonstrated, although Pb2+ and Na+ can be potentially detrimental. The presence of Pb2+ can prevent deposition of metallic Zn, forming zinc oxychloride, ZnC12.4Zn(OH)2, instead. High concentrations of Na+ can also result in precipitation of NaCl. This investigation has shown that hydrometallurgical treatment of MSW flyash through leaching, cementation and electrowinning is a potentially feasible method for simultaneous detoxification and recovery of metal values. Several issues have also been identified which would require further investigation for final process development.

Jan 1, 1993

By D. R. Tweeton, L. W. Lake

A modified push-pull field test and a computer model of cation exchange were developed to aid in evaluating cation exchange parameters prior to in situ mining. Reliable determination of these parameters is essential when modeling restoration of ground-water quality. The field test involves a much larger volume and much less disturbance to the ore sample than is feasible with laboratory measurements. This test can be per¬formed in two or three weeks. It is relatively inexpensive, requiring one injection-production well and two or more wells for collecting samples of leach solution. The use of the model in interpreting test results is illustrated with field data from an in situ uranium mine. Much of the research was performed by the University of Texas at Austin and was partially funded by the US Bureau of Mines.

Jan 1, 1987

By G. D. Schena

A decision support system for the management of the mineral resources of a developing country has been derived. The system allows the evaluation of the impact of a mineral project in a developing country in the broad context of its economy. The analysis permits the assessment of the overall socio-economic consequences of mineral prospects and allows incorporation in the evaluation of issues that are broader in scope than the pure financial objectives. The system is built around the Leontief framework of economic analysis. The original input-output model, enhanced to incorporate country-specific behaviour is integrated with cost-benefit analysis and shadow pricing. The analysis leads to synthetic measures of profitability at market and shadow prices. These measures are useful to direct the mineral policy of a developing country through the exploitation of those mineral resources which are most likely to bring about economic growth and social advancement.

Jan 1, 1992

By A. C. Beaulieu

CITY OF EDMONTON Rate of Growth The City of Edmonton has been classed by some economists as being the most progressive City in Canada since the early 50&apos;s. The high rise buildings that are changing Edmonton&apos;s skyline, the rapidly expanding sewer and water network, and the proposed rapid transit system all indicate the requirements of an ever expanding City. Edmonton, the core of Canada&apos;s Energy Empire is the country&apos;s seventh largest metropolitan area. Bisected by the 22 mile long park of its magnificent river valley, it sits in the midst of the 50,000 sq miles of riches that have created it. Underneath the City, however, extending down for thousands of feet and encircling it for a radius of scores of miles, lies a fabulous store of petroleum wealth. By the early 1940&apos;s, based upon the needs of the farming areas, accompanied by some small exploitation of coal and timber, Edmonton grew to 100,000 people. Then in a short space of 20 years Edmonton shot up to be a city of 450,000. Figure 1 (Slide No. 1) indicates the population growth in the City of Edmonton and the Census Metropolitan Area from 1906 to 1971.

Jan 1, 1997

By E. J. Peuraniemi, J. T. Yli-Penttilä, A. Jokilaakso, K. M. Riihilahti

Dust formation and the reaction mechanisms of copper matte particles were investigated in simulated flash-oxidation conditions. The granulated and ground matte consisted of 72% Cu, 4% Fe and 21 % S (by weight). Experiments were conducted by using a laminar flow furnace with a reaction-gas composition ranging from 20% to 75% O2 (by volume) in nitrogen. The particle feeding was carried out by a single-particle method, and samples were quenched after a specified reaction time ([~] 0.05 to 0.4 s) in a cold water film. Experimental temperatures ranged from 800o to 1,300o C. Chemical analysis was used to determine the degree of oxidation, and optical and scanning electron microscopes, combined with energy dispersive analysis, were used for characterization of the reacted particles.

Jan 1, 1999

By Z. M. Zavodni, M. K. McCarter

This paper identifies physical conditions responsible for past instability of the Main Hill area in Kennecott Copper Corporation&apos;s Bingham Canyon Mine, Bingham Canyon, Utah, and describes successful stabilization techniques employed in this slide zone. Geotechnical highlights of recent slides are presented, including monitoring, geological engineering data collection, hydrology, physical rock properties, and stability analyses. Local conditions responsible for slope movement in the Main Hill zone are: (1) high pore water pressure that causes a substantial decrease in real and effective material strengths; (2) continuous structural systems that allow sliding in the more competent rock zones; and (3) broad areas containing fractured, altered , and incompetent rock and soil- like materials. The failure mode is structurally controlled and involves a circular-type soil failure in the toe region initiated by excessive pore water pressure. A surface mapping method is presented which assigns rock mass quality on the basis of block size and rock substance strength. This site characterization technique has successfully predicted slide boundaries and failure modes; used in conjunction with laboratory determined shear strengths, it has provided basic input for calculating slope safety factors in the Main Hill slide zone.

Jan 1, 1977

By Jacques Deraisme

Geostatistics has been applied in many mining feasibility studies throughout the world during the last decade. Recently geostatistics has begun to be applied to the field of mining processes by attempting to aid in the definition of the best mining policy. For a feasibility study the grade-tonnage relationships give a reasonable order of magnitude estimate of the ore reserves within the deposit. But the reserves that will actually be recovered, will vary depending upon the mining methods and the technical means used. The profit earning capacity of the mining project is determined by a great many factors, such as for instance: accessibility of reserves to extracting machines, the haulage distance between the mine and the mill, the variability of produced ore (tonnage and grades) which could necessitate stockpiles or blending areas?

Jan 1, 1979

By C. J. Pritchard, R. E. Gundersen

I commend the authors on examining an interesting method of shaft lining and attempting to improve safety in a dangerous environment by remotely installing the shaft lining. It is important, though, to not trade off shaft lining safety for long-term mine safety by lining an intake shaft with combustible material. In many operations, the mine utilities are installed next to the lining of the intake shaft, supplying a possible ignition source if damaged or overloaded. Although the polyurethane studied in the paper is of relatively high density, no mention is made of the flame retardency of the samples. When exposed to heat, small amounts of polyurethane will melt and bum but are extinguished when the heat source is removed. If large surface areas of combustible polyurethane - a tunnel or mine shaft- are exposed to ignition heat sources that are not removed or extinguished early, an uncontrollable, fuel rich fire may result with high carbon monoxide levels, low oxygen concentrations, and greatly increased burning rates that can have devastating effects on the ventilation system and miners&apos; safety. Although these heavy polyurethanes lend themselves to a "pouring" application around the annulus of the shaft liners and is a continuous process, past experience with atomizing and frothing polyurethane spray systems indicates a high degree of maintenance and operator attention to the nozzle1 delivery system. This may require more miner&apos;s time to be spent in the shaft maintaining the foam system, negating some of the safety advantages of the system. If polyurethane foams are to be used in mines, they must be of the highest quality available in terms of flame spread, heat emitted while curing, and contaminants emitted while curing and spraying. In addition, employees must be given adequate training and be thoroughly informed in all aspects of polyurethane foam safety procedures. As witnessed by our fellow miners in South Africa, we can accept no less.

Jan 1, 1991

By Huayang Luo, Hui Li, Wei Zhou, Gang Chen, Scott Huang

The beach and offshore gold resources demonstrated at Nome, Alaska are some of the richest found in Alaska. They contain potentially significant resources that may be exploited in the future. Several companies have contributed to the exploration and reserve estimation in Nome offshore gold deposits. More than 3,000 holes were drilled and over 10,000 offshore samples were analyzed in the Nome offshore areas of approximately 40 km2. Those 3,000 plus drill hole logs were converted into digital formats comparable with ArcGIS software. Considerable amounts of mineral resources data were processed and visualized using ArcGIS 8.3 and its geostatistic, 3D analysis, and spatial analysis components. In this study, based on the data processing and visualization results of ArcGIS, a user-friendly website for mineral resource management and utilization is developed using ArcIMS 4.0.1. ArcIMS is a GIS solution to build and deliver maps, data, and tools over the Internet. The Nome offshore mineral resources website presents the geostatistic and GIS analysis information. This site allows clients to access the information and perform ArcGIS analysis, such as interactive data query, and map layers display of the gold resource distribution, average grade, gold reserve, and relative mineral resource estimation via remote computers. With linkage to other related mining web sites, this web site allows users to search for related publications and more flexibly manage the information. A few other appropriate customized tools are also being developed to assist interactions between the server and clients for data analysis and management.

Jan 1, 2005

By S. P. Mehrotra, P. C. Kapur

A phase-species classification is suggested for the mathematical models of flotation kinetics. Important models are discussed and the structure of their rate constants and parameters is analyzed. Split or enhancement factors are formulated for different kinetic models. The steady state dynamics of the flotation circuits can always be described in terms of these factors. For simulation of circuits, feed is characterized in a formal manner starting from a multivariate distribution of particles in flotation rate, size and mineral content. Synthesis of optimum circuits which simultaneously searches for the best process variables and structural parameters from a generalized master network is described. Trends in the areas of search algorithms, role of middlings and feed identification etc. are indicated.

Jan 1, 1989

By L. L. Gagné

The Churchill Falls Development will eventually be the largest source of hydroelectric power in North America. Churchill Falls was discovered in 1839, but until recent years it was not practical to begin development of this site to tap the 7 million horsepower available. This $1 billion project is located in Labrador, 700 miles northeast of Montreal and 650 miles northwest of St. Johns, Nfld. The construction will divert the Churchill River 5 miles upstream from the 245 foot Churchill Falls. Rapids above and below the Falls, together with the Falls proper, give a natural head of 1,040 feet. In contrast to the basic simplicity of the surface installations, the powerhouse labyrinth is astounding in size and complexity. The largest in the world, it consists of three major chambers - the powerhouse, 972 feet long by 81 feet wide and 154 feet high; the surge chamber, 763 feet long, 40 feet to 64 feet wide and 148 feet high; and the transformer gallery, 856 feet long by 50 feet wide and 39 feet high. Other major features include eleven inclined penstocks, each 1200 feet long and 20 feet in finished diameter; eleven draft tubes averaging 37 feet in finished diameter and 162 feet long; six vertical cable shafts each an average of 865 feet in length; a series of eleven short bus tunnels linking the powerhouse and the transformer gallery; a vertical power-

Jan 1, 1997

By Jeffrey J. Schwoebel, Jianliang Li, Daniel J. Brunner

A United Nations (UN) administered degasification technology transfer project, funded by the Global Environmental Fund (GEF) is underway at the Shihao Mine of the Songzao Coal Mining Ad- ministration in the province of Sichuan, Peoples Republic of China. This mine exploits multiple seams at depths ranging from 300 to 600 m below surface. In-seam boreholes and frequently spaced in-mine vertical boreholes, developed from underlying galleries constructed specifically for this purpose, currently degasify the seams in advance of mining at the Shihao Mine. Because of ventilation system constraints and the in-situ gas con- tent, longwall mining of the coals at this mine could not proceed without some form of pre-mining degasification. This paper presents a simulation based degasification plan of long, in-seam horizontal boreholes for the Shihao Mine. Simulations with a coalbed reservoir program assessed time dependent degasification characteristics of both vertical and in-seam horizontal boreholes. The simulations used input data from reservoir and desorption tests conducted at the mine site. The results produced system design nomograms to assist mine engineers in defining the appropriate borehole spacing necessary to degasify the seam in the time available for pre-mining drainage. The predicted effectiveness of the current vertical degasification scheme was compared with that for a horizontal borehole program and served as the basis for the recommended in-seam borehole configuration for the project at the Shihao Mine. The horizontal borehole degasification program requires substantially less gallery and borehole development than the present vertical degasification scheme.

Jan 1, 1997

By J. Brent Hiskey

INTRODUCTION Metal electrodeposition processes are of fundamental technological importance to a number of fields. Electrorefining, electrowinning, electroplating, and electrogalvanizing have all been the subject of intense study for over a century. More recently, electrochem- ical deposition has played a critical role in advances in microelectronics and lately has been an enabling technology for the production of certain nanostructured materials. Electrometallurgists have most frequently been concerned with the structure and morphology of massive deposits. For example, in metal recovery steps such as electrorefining and electrowinning, deposits demonstrating adherent coarse-grained characteristics are most desirable. In the case of electroplating, a bright fine-grained, tenacious and strongly adherent deposit is required. The fabrication of microelectronic devices and the production of nanoscale structures such as nanoparticles, nanowires, and nanorods requires a keen understanding of early stage deposition effects. The initial stages of metal deposition, usually referred to as electroclystallization, are fundamentally linked to nucleation and growth phenomena. Early stage deposits are typically very ordered. Whereas, bulk metal deposition structures are much more ran- dom. In both cases, the discharge of a metal ion at an electrified interface is represented by simple cathodic reduction as follows: [ ] Me(H2O)xn[ ] is a hydrated metal ion residing in the bulk solution and Me is the metal atom occupying a crystallographic lattice position. A similar reduction reaction can be

Jan 1, 2005

By J. Twining, V. Nguyen, J. Perera

A computer code for ecological risk assessment (ERA), AQUARISK, has been developed and applied to evaluate the likelihood of biotic detriment due to exposure to acid rock drainage (ARD) from the Burkunga mine site in Australia Stream water quality monitoring data were used for the assessment and were compared with a) national water quality guidelines, b) literature derived ecotoxicology data and c) biological monitoring data. With bioavailability calculations, the code predicted that, for metals exceeding the guidelines, 44% of macroinvertebrate species above the mine and 100% below the mine would be adversely affected by the metals in the stream. This compares reasonably and conservatively with biological monitoring that showed observed reductions of 41% and 85% of species respectively at each site. Using literature data for macroinvertebrates to predict impact produced similar estimates to using data for all taxa. Use of speciation modeling also lessened the degree of reduction in the median water metal concentrations required to achieve acceptable impact (measured either by exceedence of criteria or by species likely to be affected) by a factor of 75%. This result implies significant economic and management benefits in relation to remedial engineering or water treatment options for sites.

Jan 1, 2000

By David S. Bolin, Gary R. Peterson

INTRODUCTION In both the United States and Canada, a company making a public offering of securities must comply with regulations which have been promulgated by Federal and/or Provincial Legislatures. This paper focuses on the regulations pertaining to reserve reports required by the United States Securities and Exchange Commission (SEC). SEC RESERVE FILINGS Reserve reports made to the United States Securities and Exchange Commission are the only reserve reports which are directly regulated by the United States government. The requirements for SEC reserve reports are set forth in the filing forms as shown in Appendix A, from Item 17A of SEC Form S-18. These reporting requirements, which are intended to protect the investing public from inaccurate or misleading claims, are primarily oriented to S-1 or other filings for new stock issues but must also be followed for annual 10K reports which must be filed annually by U.S. public corporations as part of the Corporate Annual Report. These undertakings require independent audits of reserves, mine designs, plant facilities and a general economic evaluation of the planned or existing operation as part of the backup documents for filing. An ore reserve is defined by the SEC as "That part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination". This definition is unchanged since it was last

Jan 1, 1988

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&apos;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