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By James Wm. White

Computer-based mine management systems are being used in many surface mines to assign haul trucks, track equipment and manage information. Advances in digital communications allow these systems to be used in underground operations. Underground mine management systems help maximize production by providing gains in equipment and manpower use, drawpoint equalization in block caving operations, preventive maintenance and safety. Current systems use allocated or "locked" train and load-haul-dump (LHD) dispatching. Allocated dispatching rarely optimizes open pit product' on. But it offers an efficient mode of operation underground and where options are more limited. The primary objectives of underground mine management systems are to maximize production and mini¬mize contention time through allocated train, truck or LHD dispatching, traffic control, equipment monitoring and comprehensive reporting. The main components of an underground mine management system include: ? A central computer (personal computer or worksta¬tion) in a central control center. It sends instructions to train, truck or LHD drivers and allows dispatcher interaction. ? A field computer system (FCS). This consists of a touch-screen graphics console (GC) and mobile hub - on each train, truck or LHD to receive and display instructions from the central computer and accept driver input. ? A data radio network based on leaky feeder (data, voice, video) or microcell radios (data only) and advanced token-ring technology. This passes information between the central computer and the FCSs. ? Radio frequency (RF) tags mounted at boxes, weigh bridges, tips and rim tunnel main haulage ways to locate trains or LHDs (Luke, 1993). Such a management system must be in place before implementing computer-based dispatching (Vagenas, 1991) for production optimization.

Jan 1, 1997

By Kim A. Lapakko, David A. Antonson, Jon R. Wagner

This study examined the potential of mixing rotary kiln fines (RK fines), a waste product generated when limestone is converted to lime (CaO), with acid producing mine waste to provide 1) short-term mitigation by neutralizing acid produced by iron sulfide oxidation and 2) long-term mitigation by facilitating the passivation of iron sulfide mineral surfaces. Five loadings of RK fines were mixed with 75 g of Duluth Complex rock to produce neutralization potential (NP) added: acid potential (AP) quotients of 0,0.11,0.22,0.66 and 1.1. The mixtures were subjected to wet-dry cycling laboratory testing for 585 weeks. The rock alone produced acidic drainage, with pH decreasing below 4 after about 20 weeks of reaction and ultimately reaching the approximate range of 3.3 to 3.5; sulfate release did not decrease over time. The RK fines elevated pH and inhibited sulfate release for time periods which increased with the mass of RK fines present. The pH of drainage from the 0.11 quotient (NP added1AP) loading decreased below 6.0 after 75 weeks of dissolution and decreased to 3.6 after 117 weeks, at which time the reactor was terminated. The duplicate 0.22 quotient loadings of RK fines decreased below 6.0 after 95 and 170 weeks. The former was terminated after 117 weeks, and the latter reached a minimum pH of 2.8 after 512 weeks. Drainage pH from the 0.66 quotient decreased below 6 after 581 weeks. For the drainages which acidified, the cumulative calcium release prior to pH decreasing below 6.0 was 92 to 103 percent of that initially present as calcium carbonateloxide in the RK fines. The pH of drainage from the 1.1 quotient typically remained above 8.0 throughout the period of record. Sulfate concentrations in the drainages decreased while the neutralizing fraction of the RK fines was present, but increased after this fraction was depleted.

Jan 1, 2000

By Oleg N. Tikhonov

The paper deals with computerized analytical design of separational mineral processing flowsheets for flotation, gravity separation, magnetic separation, etc. (without comminution). Initial data include fractional composition of the feed ore, separational characteristics of the unit operations, and optimality criterion. Computer-calculated results display optimal flowsheet configuration and optimal parameters of unit operations like tonnage, residence time, etc., which allows the choice of equipment. An example of apatite flotation flowsheet design is given. This analytical approach may be used for automatic process control purposes as well.

Jan 1, 1989

By J. G. Groppo, D. J. Sung, B. K. Parekh

Hyperbaric filtration for the dewatering of fine coal cleaned by froth flotation was evaluated on a laboratory scale. A laboratory pressure filtration procedure designed to obtain a uniform cake structure from dilute slurries containing a significant amount of coarse material is described. Baseline tests were conducted to determine the optimum operating conditions for the eventual application of the process to a continuous pilot-scale hyperbaric filter. Investigated were filter operating parameters such as driving force, time, cake thickness, percent solids, viscosity and pH.

Jan 1, 1996

By M. K. Han, K. N. Han, P. B. Queneau, W. J. Dawson

The development and scale up of hydrothermal synthesis processes for manufacture of high performance materials is discussed. Traditional hydrometallurgical processes are reviewed, leading into a discussion of process development concerns for manufacture of modern materials. Three case studies are presented, including a piezoelectric ceramic, barium titanate for multiyear capacitors, and high purity chromium metal. Factors for selection of reactor design are presented, as well as results of scale-up studies on the three products.

Jan 1, 1993

By Eric Monrad

Discrete event simulation modeling provides a tool to quantify the throughput capacity of stockyards. Interactions between the main equipment types (trains, dumpers, conveyors, stackers, reclaimers, shiploaders) can be captured, including route blockages, breakdowns, and planned maintenance. Simulation has been successfully used at world-class stockyard facilities to determine current capacity and to identify gains resulting from improvement projects. Recent projects have focused on iron-ore, coal, and soya facilities, but the technology is suitable to be used on any bulk material type.

Jan 1, 2008

By Isiah M. Warner, Philip Oldham, John Kennedy, Bennett D. Lass

A new method for determination of residual flotation oils on beneficiated kaolin clays has been developed The method, which yields qualitative information, is based on fluorescence measurements employing a spatially resolved, polychromatic illumination source for excitation, and a two-dimensional detection scheme using a silicon-intensified, video imaging device The method was used to identify residual oils on a beneficiated, Washington County, Georgia, crude clay The results were compared to a similar qualitative analysis performed via capillary column gas chromatography using a flame ionization detector The video fluorometry was the preferred method of analysis

Jan 1, 1983

By J. P. Savely

This paper describes the development of a trim blast design to improve the stability of a final pit wall. Description is given of the effects of rock characteristics, rock type, and pit plans on the blast design. Currently, six benches have been mined with trim blasting. A more stable final wall has resulted and the successful program has reduced mining costs over an extended time period. Low-cost blast monitoring and field observation were used to determine peak particle velocity and blast damage. Using criteria developed from this relationship, trim blasts were designed and evaluated.

Jan 1, 1987

By M. Sagisaka

Coal is expected as one of the main energy sources for a long period because of vast deposits. However, two large barriers to utilize it are suggested, i.e. the carbon dioxide emissions and ash disposal. The authors chose principal methods and areas to utilize coal ash and analyzed the environmental impacts caused by the ash treatment considering the source of the ash. According to the analysis based on lifecycle thinking, an optimized ash treatment system can reduce the integrated environmental impact. It suggests that coal can carry out its role for several decades without disturbances from the point of ash treatment.

Jan 1, 2006

By L. D. Bowerman

The topic of the presentation will be the excavation of 25,000 IF, 11-foot 0-inch diameter, hard rock tunnel using a Robbins boring machine on the Terror Lake Hydroelectric Project on Kodiak Island, Alaska. This tunnel was completed on a tight construction schedule under some unusual conditions. The tunnel was mined through hard massive granite with faults and high water flows up to 7,000 GPM encountered at the heading in some areas. New innovations in equipment and cutter design were used.

Jan 1, 1985

By P. A. Plunkert

Metallurgical-grade bauxite was imported into the United States from 11 countries in 2004. The principal suppliers of this 10 Mt (11 million st) of imported ore were Jamaica (33 percent), Brazil (25 percent), Guinea(23 percent) and Guyana (11 percent). The average value of imports, cost, insurance and freight (c.i.f.) U.S. ports, was $31/t ($28/st). Calcined refractory-grade bauxite imports were 165kt (182,000 st) with an average value of $146/t ($132/st), c.i.f. U.S. ports. China supplied 70 percent; Guyana, 22

Jan 1, 2005

Rising energy costs are a growing concern among mine operators. At sur’ace operations, the size of a dragline, production requirements, pit geometry and layout, and operator skill are all factors in potential energy savings. The following tips are offered as a practical means to conserve energy demand, and can be applied to diesel fuel draglines as well.

Jan 7, 1980

By A. Haile, A. Poole

During 2001-2002, the Granny Smith Mine of Western Australia undertook the development of a planned circular failure. Excavation took place in an interim pit wall that intersected the transported sediments, lake clays, and palaeo channel sands that overlay the deposit. The purpose of the study was to refine feasibility level slope parameters used for the initial design of the Wallaby pit, with the intent of increasing the overall slope when excavating the ultimate pit limits. During excavation, the geological and hydrogeological characteristics were studied in detail and data was collected using area-specific instrumentation and monitoring. Failure occurred in mid February 2002, at which time a detailed survey of the excavated slope using laser technology was conducted to provide geometric information suitable for back analysis of the material shear strength. The slope failure and associated information was analysed by geotechnical consultants. The revised shear strength and hydrogeological parameters were then applied to design the final pit walls. The slope redesign provided a cost saving of approximately seven hundred thousand US dollars. Design, slope formation, back analysis, the geology of the clay units, the hydrological environment, planned infrastructure, management and safety issues, and the on-going slope performance of the final slope are discussed.

Jan 1, 2004

By S. D. Thompson

Conveyor belt haulage has become the preferred mainline transport method in under-ground coal mining, especially for multi-unit mines. Optimum designs for belts (width and speed) and surge bins (placement, capacity, and discharge rate) are necessary for minimizing haulage cost. Two computer simulation models, CMaCS and BELTSIM, available for optimizing these designs are compared. These comparison include: modeling, input data requirements, statistical flexibility, accuracy of simulated loading, and execution time.

Jan 1, 1989

By Luis R. Bittencourt

Research efforts have been made to characterize a refractory Brazilian bauxite ore composed basically of gibbsite, kaolinite and quartz. Detailed polished-section microprobe analysis of the unbroken ore has been used to describe the liberation characteristics and the association between mineral phases. The linear grade distributions for selected particle size fractions were determined by means? of a particular implementation of King's Random Fracture Model that uses the exponential model for the distribution of linear intercepts through both dispersed (kaolinite) and continuous (gibbsite) phases. The corresponding volumetric grade distributions were then determined by means of a constrained optimization technique for the solution of the transformation equation. Batch flotation experiments were carried out to determine the kinetics for particles of different sizes and the results correlated with the liberation spectrum for each size class.

Jan 1, 1991

By Kristian E. Waters, Hao Ma, Haibei Wang

Heavy metal ions exist in waste effluents including mining tailings, manufacturing discharges, and smelting and metal plating process wastes. Various methods are available to treat industrial effluents containing high levels of metal ions, but when confronted with wastewater that has low metal ion concentration below 500 mg/L, most techniques suffer from low removal or separation efficiency as well as high operating cost. ELM-based techniques can be used to solve these problems.

Apr 1, 2023

By R. O. Vernon

The Florida Peninsula has existed as a part of a much broader plateau, since at least the Early Cretaceous. This plateau, the Floridan Plateau, now consists of the present peninsula and a broad submerged shelf of equivalent size extending the length of the state and out into the Gulf of Mexico. Florida Peninsula was separated from the mainland United States by a negative area called the Suwannee Straits. To the south of this feature existed an environment similar to today?s Bahamo Banks where very pure calcium and magnesium carbonates with associated evaporites were deposited. Thus the Eocene and Oligocene contain little or no quartz sand or clay minerals except in the Panhandle west of the Suwannee Straits where some clastics were contributed by rivers from the north.

Jan 1, 1966

By R. L. McNearny

A comparison study was conducted between an actual physical model and a numerical model based on the physical model of the block cave mining method. Results from the numerical analyses closely simulated the blocky behavior of the physical models, including bridging and interlocking of the simulated orebody during draw. The draw-down patterns and the rate of draw developed during numerical modeling also closely simulated the physical models. An unexpected result from the numerical modeling was the development of a zone of downward deflection which preceded the development of the zone of material movement.

Jan 1, 1997

By V. Voller

A relatively simple model of grinding which incorporates both the Bond grindability equations and the population balance equations has been extended to form a comprehensive simulation package that can describe most kinds of conventional grinding circuits. The package has two programs, with the first consisting of an input program which helps the user to specify the prescribed circuit, while the second program performs the actual simulation. The package serves two main purposes - i) as a check on mill design, with the output providing not only predictions for the product passing size but also of the full product size distribution, and ii) as a means to assess the likely effects on the product size distribution of operating under different sets of conditions.

Jan 1, 1981

By K. E. Kolm, W. H. Langer

Developing natural aggregate resources (sand, gravel and stone) creates environmental impacts. A systems analysis method was designed to characterize the components of the environmental system, identify potential impacts to those systems and evaluate the extent of those impacts. The stepwise method consists of problem definition, data collection, preliminary conceptualization and characterization, additional data collection, data analysis and refinement. The method requires analyzes of various systems making up the environment, including land surface, geomorphic, subsurface and groundwater systems. After system characterization is complete, the method focuses on identifying and evaluating potential environmental impacts to determine acceptable mining strategies.

Jan 1, 2003