Search Documents

By S. Ersayin, I. Iwasaki

The application of a magnetic field was shown to be effective in controlling iron losses in a pilot-scale cationic silica fIotation in the processing of magnetic taconite concentrates. The design of a magnetic field distribution device and batch flotation test results using a 1.42-m3 (50 cu ft) WEMCO flotation cell are reported. Major losses of iron units in froth products were in the -25-µm (-500-mesh) fraction, and the application of a magnetic field decreased the flotation of fine magnetite, thereby improving the selectivity of separation. The "as-received" sample was sufficiently magnetized, and no further benefit was gained by the magnetizing treatment. The selectivity was somewhat adversely affected by demagnetizing the sample, though its effect was minimal due to the magnetic field. The device is simple in construction, low cost and may be readily installed in existing equipment. Key words: Iron ore, Flotation, Taconite concentrates, Cationic silica flotation, Magnetic field, Flexible magnetic sheet, Magnetizing, Demagnetizing

Jan 1, 2003

By P. J. Tarkoy

To successfully bid a tunneling contract by machine, a contractor must have a reliable estimate of expected penetration rates and cutter costs. Preferably, these predictions should be independent of those supplied by machine and cutter manufacturers. Therefore, a series of rock index tests have been developed and incorporated in routine Rock Mechanics testing for the purpose of predicting rock boreability. Index properties were evaluated empirically by using rock samples and pertinent construction records from recently machined tunnels. Samples were taken from the completed tunnel walls, tested parallel to machine penetration, and results were compared to localized rates of penetration. Indices are based on two measures of rebound hardness and two measures of abrasive properties. The Shore (C-2 type) Scleroscope and Schmidt (L-type) Hammer were utilized to measure rebound hardness and a Taber Abraser was modified to measure rock abrasiveness and abradeability. Results indicate that rock hardness index properties investigated in this study can be used successfully to predict TBM penetration rates.

Jan 1, 1974

By Jerry Peterson

Mine maintenance planning, scheduling and daily workflow communications are crucial elements for enhancing overall efficiency and reducing costs. Equally important, it helps identify time periods that equipment will be unavailable so conflicts with production demands are avoided. The current CMMS Kennecott Energy Corporation (KEC) utilizes does not perform these functions in an effective manner. A solution to this problem was to develop an intuitive web-based maintenance planning, scheduling and work flow system call E-MESA. This paper will discuss the E-MESA'S system structure and advantages and disadvantages of using the web based E-MESA solution to perform the maintenance functions described above.

Jan 1, 2002

By V. J. Kecojevic, W. A. Wilkinson

Mining companies are increasingly looking at Global Positioning System (GPS) technology coupled with 3D mine planning and visualization systems to deliver increased productivity and reduction in operating costs in drilling and blasting operations. Leveraging GPS into drill and blast operations requires that a drilling plan be developed and imported into the GPS to guide the operation to a planned and desirable outcome. State-of-the-art mine planning software systems provide the engineer with a 3D environment in which to design and visualize drill and blast plans. This paper discusses producing and exporting 3D drill and blast plans to GPS and how some coal companies are utilizing GPS and mine planning software technology in the drill and blast process.

Jan 1, 2004

By Gregory W. Gustina, Terry P. Boyle

Analysis of the structure of the benthic macroinvertebrate community, consisting of the number of taxa and the relative distribution of total numbers, is a routine method of assessing the ecological quality of streams. Various multivariate statistical techniques, which assess the structural variability of the benthic macroinvertebrate community and the relationship of that variability with natural and anthropogenic environmental variables, have utility in separation of the various physical and chemical factors associated with impact. Multivariate methodology, while computationally complex is statistically rigorous and better integrates physical, chemical, and biological data for more synthetic interpretation. Using the multivariate analysis technique, canonical correspondence analysis, we have analyzed a number of sites in the upper Boulder River Basin, Montana to determine which are the important environmental variables associated with variation in community structure. The results of this analysis an integrated with more traditional analysis of community structure and incorporated in a risk analysis for the mediation of abandoned mines and mill sites within the watershed.

Jan 1, 2000

By X. K. Jiang

Pneumatic, triboelectrostatic processing of physical mixtures containing fine (-200 mesh) particulate may have significant application potential in the mining and energy industries. Such dry processing methods, especially for finely comminuted materials, have not been examined in as much detail as wet processing methods nor have been part of the training or education of mining and process engineers. We have examined fundamental and applied physical and engineering factors controlling triboelectrostatic beneficiation of fine-sized physical mixtures, one of which -combustion fly ash -has size, heterogeneity and mineral concentrations typical of those expected in mined minerals. The applicability of dry processing, however, cannot be readily evaluated because of the unavailability of standard procedures for process assessment.

Jan 1, 1999

By Kent S. Roessler

The Bureau of Mines is currently investigating the geophysical application of Tomography to monitor leachate during in-situ mining. Determining the location of the leachate is important for both economic and environmental reasons. By analyzing a sequence of tomographic images, we can determine where highly permeable/fractured regions are located and hence, major flow paths. Since BOMTOM (Bureau Of Mines TOMography - Tomographic Reconstruction Program), and BOMCRATR (Bureau Of Mines Curved RAy Tomography - Tomographic Reconstruction Program) are sensitive to user-selected ray path arrival times, we are also investigating the use of neural networks to automate the process of recognizing this feature. This paper presents a technique for detecting fracture zones and their orientations in a region between two boreholes, by using a motion analysis study of a sequence of tomographic images. It also addresses the need for an automated/unbiased method to pick crosshole seismic arrival times using a trained neural network. In exploration geophysics, the picking of first break arrivals represents a pattern recognition task. The neural net paradigm has proved to be a good method of solving this type of task. To pick the first arrival peak of a trace, the network is trained with a set of known (user selected) first arrival peaks by creating a binary image of a set of traces. Once trained, the neural net correctly picked first arrivals of the remaining traces in the set.

Jan 1, 1992

By Arthur B. Steiker

Digital simulation was used to model a proposed underground' train system. The trains are to haul ore from numerous loading points beneath the production area of the mine to a central underground dump location, and then return to the mine. The purpose of the simulation was to aid mine engineers in studying various alternatives and configurations regarding track layout, crusher (dump point) specifications, dispatch procedures, fleet size, and train length, among others. The simulation' model can also be used to study the same aspects of existing haulage systems. To accommodate a wide and initially unknown range of system designs, a modular model structure was developed with major components devoted to track routing, train movement, loading process, dumping process, and dispatch. Key statistics tabulated were number of trains dumped during a simulated week, queueing delays in the mine and at the crusher, crusher utilization, cycle time, and percent of time for each: activity (loading, moving, dumping, etc.). The simulation results were instrumental in identifying a train system design which would reduce queueing delays and meet production goals with a minimum of trains and track mileage.

Jan 1, 1982

By Liu Hongkang, M. J. Virnig, Yang Xianwan, Zhu Yun

A new technology for recovery of gold from loaded carbon developed by Kunming Institute of Technology is introduced. The principle, production practice and results are described.

Jan 1, 1993

By W. A. Rickelton, A. J. Robertson

The ability of triisobutylphosphine sulfides to selectively recover silver from acidic sulfate solutions containing zinc and copper is described. Selectivity is explained in terms of the concept of hard and son Lewis acids and bases. Silver is stripped from the solvent using a novel strip feed (thiosulfate salt), and the recovery of metallic silver from the strip liquor by electrolysis or cementation is suggested. The high selectivity of extraction for silver and the utility of the stripping reagent are demonstrated in continuous, countercurrent, mini-plant tests. Important reagent properties, such as hydrolytic stability and low aqueous solubility, are discussed.

Jan 1, 1988

By Daniel J. Kennedy, George W. Klinowski

A significant portion of each mine is ventilated with the help of auxiliary fans delivering fresh air to the faces of its developing headings via flexible or rigid ducts. Quality and volumes of air delivered to the blind working faces are essential for creation of safe and acceptable conditions for employed crews. Well designed and properly maintained delivery systems are necessary in each mine. The Cape Breton Coal Research Laboratory, part of the Canada Centre for Mineral and Energy Technology located in Sydney, Nova Scotia, Canada, developed a tracer gas based technique which provides fast and accurate evaluation of any auxiliary ventilation system performance. In addition, important information about the system's behaviour is gathered which can be used for designing a similar system in comparable conditions.

Jan 1, 1989

By A. G. Sciulli, G. P. Ballock, K. K. Wu

This paper discusses common environmental problems associated with coal refuse disposal. It suggests design concepts to minimize potential hazards. Discussion focuses on site selection, embankment design and construction, site preparation, facility operation, abandonment, and reclamation. It emphasizes measures that should be adopted in the design phases and during construction of the facility. Recommendations are also made concerning special problems, including seepage, ground water contamination, and mine sealing.

Jan 1, 1987

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

When longwall equipment is being specified, a nominal capacity is generally given on which to base the design of the various face and out-bye systems and components. This capacity generally comes from a nominal annual capacity requirement based on realistic utilization rates. From illustrative examples of simple system simulation, this paper sets out to show that a single nominal capacity is not sufficient to size the different systems. The manner in which the Longwall is operated and the overall system configuration and availability can have a significant impact on overall productivity.

Jan 1, 2008

By T. Vincze

Effective coal mine face ventilation, for remotely controlled and automated mining systems, is essential for the control of methane. The evolution of new mining equipment and methods has required changes and improvements in face ventilation methods. One emphasis today is on the use of remotely operated and automated mining systems that can be used to make continuous cuts of 6 m (20 ft) and deeper. U.S. Bureau of Mines research is studying ways to more effectively ventilate these extended cuts. Two face ventilation techniques that utilize either blowing brattice or a jet fan for deep cutting are examined in this paper. Bureau of Mines procedures for evaluating face ventilation systems are also discussed.

Jan 1, 1992

By J. F. T. Agapito, C. E. Brechtel, C. J. Gilbert, T. R. Kelly, R. C. Karlson

A multi-lift benching cut-and-fill mining method was adopted at Asamera Minerals (U. S.), Inc.'s Cannon Mine to balance the goals of high productivity and near 100 percent recovery with the need to minimize subsidence. High strength backfill was required to provide effective long-term overburden support and safe working conditions during the pillar recovery operations. Operational designs were evaluated using numerical modeling to predict global mine stability and backfill strength requirements. These models incorporated sequential mining of primary stopes, backfilling of primary stopes and recovery of pillars, and have been transferred to the mine operations group for use in evaluating different production sequences. The modeling has provided a better understanding of the structural response of the mine to excavation of the primary stopes and removal of the pillars. Predictions about the transfer of overburden weight to the abutments, pillars and cemented fill pillars have provided a criterion to evaluate mining plans and production sequence. Comparison of these predictions with actual mine structural performance has developed confidence in the design of the mining method and in the geomechanical design methods being employed. Primary mining of the B-North zone is nearly complete, and the stopes have been generally stable, as projected in the original design. Some exceptions have occurred where locally stope pillars have failed due to the presence of adversely oriented sheared beds. Recovery of the pillars between the

Jan 1, 1987

By K. G. Sutterer, P. T. Wang, R. Sweigard

One possible alternative for the disposal of flue gas desulfurization (FGD) by-products is to use it as backfilling support material in highwall mine adits. The finite element method was used to analyze the variation in stresses and displacements within and around a highwall adit backfilled with FGD materials. The engineering properties of the rock material and the optimum mix of the FGD materials were obtained from laboratory tests. Finite element analyses show that, for the case in question, the roof displacement would decrease about 48% and the peak stress could be decreased by about 58%. The study indicates that fairly weak FGD materials can eventually lead to the stability of backfilled highwall adits.

Jan 1, 1998

By R. L. Lewis

A simple method for estimating the steady-state water quality of a pit lake is presented. The steady-state concentration of a conservative chemical constituent in a pit lake is shown to be a simple function of the inflow rate, the evaporation rate and the inflow concentration. An analytical method is presented for estimating the equilibrium ground water-inflow rate for use in water-quality predictions. The time required to reach chemical steady state is estimated using an iterative mass-balance model. Mine operators should find the methodology useful for planning and screening regulatory applications where conservative estimates of pit lake water quality are desirable.

Jan 1, 2000

By Douglas W. Fuerstenau

Technological innovation is needed to meet the challenges that face the mineral industry because ores steadily become lower in grade, more complex in mineralogy, and must be processed in the face of ever- increasing environmental constraints and increased costs. How periodic innovation in mineral processing helped overcome the challenges that faced the mineral industry is briefly traced from antiquity up to the present time.

Jan 1, 1989

By Pascale St-Germain, Michael Li, Lionel J. J. Catalan

The oxygen flux into water-covered reactive sulphidic tailings is required for evaluating the long-term performance and predicting the quality of engineered shallow water covers. This information can also serve as an input to the design of water covers for reactive tailings decommissioning. This paper describes some dissolved oxygen (DO) profiles recently measured in the field across the tailings/water interface and oxygen fluxes derived from these profiles. These fluxes are compared with previously reported flux values from similar field measurements. Techniques and pitfalls for measuring DO profiles and calculating oxygen fluxes are also discussed.

Jan 1, 2000