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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 John T. Awald

The efficiency of search for porphyry copper and molybdenum deposits can be greatly increased. A model exploration system is here presented to show how geologic literature data and field surveys can be aided by modern statistical and computer methods. Assuming that major ore deposits occur in clusters, it is possible to evaluate rapidly large areas at modest cost and with minimum investment risk. An example of the success of these methods is given. Clusters of mine density and metal production covering the State of Nevada were plotted and machine contoured. Selection of a 47,300 square-mile area on the Nevada-California border was made. Within this area, detailed analyses were performed, and a 3000 square-mile site was picked for subsequent field examination. To initiate efficiently the field work, 81 stream sediment geochemical samples were collected and analyzed for copper, zinc, and molybdenum. These data established local variance and necessary statistical controls. Following this, a total of 151 geochemical samples were used to survey the 3000 square-mile area. Computer contouring of results directed attention to specific target areas for detailed geologic analysis, property acquisition and drilling. A total of 22 copper-zinc and molybdenum anomalies were identified. Four of these were recommended for further exploration. To date, two have been acquired and drilled and preliminary ore reserve and financial analysis have been made on one. The estimated cost and time for the regional exploration phases leading to these targets were thirty man-weeks and $16,000.

Jan 1, 1973

By Josh Struble, Fu Yuet, Jan Zywiel, Kevin King

This paper discusses the application of Integrated Inertial/GPS technology for position determination of earthmoving equipment in an open-pit mine. Different GPS augmentation methodologies are introduced and discussed. Principles for the operation of the Applanix POS MC (Position and Orientation System for Machine Control) are also presented, together with test results conducted at the Twin Creeks Newmont mine, using the POS MC and Caterpillar’s CAES (Computer Aided Earthmoving System).

Jan 1, 2005

By J. M. Scharer, Bruce E. Halbert, Pettit. Carol M., Lysane Bolduc

The ratio of neutralization potential (NP) to acid production (AP) ratio is often employed for predicting acidic discharges from waste rock dumps. The available NP was evaluated in laboratory studies of limestone dissolution in simulated acidic mine water. The available neutralization potential strongly depended on the particle size. Using limestone particles of 114" (6.4 mm) or greater, less than 20% of the total neutralization potential was exhausted at the onset of acid conditions. Apparently, the dissolution of limestone became mass transfer limited. Under mass transfer limitations, the rate of pyrite oxidation may exceed the rate of neutralization by buffering minerals. The implications concerning the controls on limestone dissolution were examined using a geochemical predictive model for sulphide mineral oxidation in waste rock. The results have shown that in case of heterogeneous waste rock piles the NP/AP ratio is a reliable indicator for short-tam predictions only. Kinetic data on the depletion rate of the neutralizing minerals and geochemical modelling suggest that waste rock environments with NP/AP ratios as high as 5.0 may turn acidic in the long term.

Jan 1, 2000

By M. V. K. Reddy

A differential flotation process for recovery of molybdenite from chalcopyrite concentrates produced at Rakha Copper Concentrator, Bihar, India has been developed. The flowsheet is simple, and relatively inexpensive and yields a concentrate assaying not less than 45% Mo at a recovery of minimum 65%, starting from chalcopyrite concentrate assaying 0.4% Mo. The consumption of the main depressant used, sodium sulphide is not more than 25 kg/t of copper concentrate processed without steaming; and with steaming the consumption was brought dorm to less than 12 kg/t of concentrate. Further reduction is possible by optimization of steaming parameters. Based on laboratory experimental results, further tests were conducted on concentrator site and process design parameters were established for design of commercial plant.

Jan 1, 1982

By A. D. Unsted

The Premier mine has been in existence for over 75 years and is closely woven into the glamour of the history of South Africa. A note on the geological formation of the diamond pipe and the gabbro gives a clearer overall picture of the mine. Mining methods for operations above and below the gabbro sill are briefly discussed. Ventilation arrangements for mining above the sill are briefly described and possible ventilation arrangements for mining below the sill are discussed in more detail. Note: conversions to S.I. units are not exact as rounding has been done.

Jan 1, 1980

By R. L. Wiegel

Several mineral process modeling and simulation packages are currently available for use in evaluating the performance of alternative process flow schemes. A critical link that has been missing from these packages is the ability to quantitatively model the effect of size reduction on the liberation of the valuable and waste minerals in the ore being processed. Although there have been several approaches taken to this problem over the past 25 years, none of them has led to a satisfactory conclusion. A technique was developed for measuring the effective liberation characteristics of magnetic taconite ores, and a program was constructed that makes use of these liberation characteristics in simultaneously simulating both size reduction and mineral liberation as it occurs in tumbling mills. This is an especially important step in the modeling of magnetic taconite processes, where magnetic rejection of low-grade wastes between grinding stages mandates that a predictive capability be available. The current application is specific to magnetic taconite, but it is possible that a similar approach could be used for other types of mineral systems. Key words: Modeling and simulation, Size reduction, Mineral liberation, Taconite, Magnetic concentrator

Jan 1, 2003

By H. Huang, J. C. Wu, C. H. Xie, Y. Q. Xue, Z. H. Zhang

Two- and three-dimensional groundwater flow models for dewatering in an opencast mine are presented. The models focus on solving special problems using numerical simulations of the opencast mine. These special problems include the drying up of the aquifer, the movement of the model boundary and the prediction of the residual head. These models are used to describe the decline of groumdwater levels in the Yuanbaoshan Opencast Coal Mine and its neighboring area during the drainage period. The simulated values agree very well with the field data. There have been several successful examples of numerical simulation for predicting the mine dewatering rate in an opencast mine. However, The hydrogeological conditions for the Yuanbaoshan Opencast Coal Mine are rather complex, and the total average flow rate is very high at 4.676 x 105 m3/d (1.65 x 107 cu ft/day). In this paper, a two-dimensional groundwater flow model in a large area is developed to solve the problems mentioned above by simulating regional drawdowns of the groundwater level during the drainage period, and a three-dimensional flow model is developed to simulate the residual head near the open-pit bench.

Jan 1, 1998

By P. K. Berger, G. T. Lineberry, H. P. Cole, J. V. Haley

Sixty-five simulation exercises were developed for teaching and testing problem solving and decision making skills to miners and mining engineers. The exercises focused on judgment and decision making for preventing and controlling mine emergencies. The structure and field testing of the exercises are described, and sample frames of individual exercises are presented. Empirical data are summarized about the effectiveness of these simulations based on the performance scores of a national sample of miners and mining engineers.

Jan 1, 1994

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 Harold E. Goetzman, Blair R. Benner, Shaolin Zhong, Rodney L. Bleifuss

A commercial high pressure roller press (KHD 90125) was installed at the Coleraine Minerals Research Laboratory for testing in October, 1994. Pilot plant evaluation of the high pressure roller press has shown that it can be used as an alternative to the rod mill for the comminution of taconite. A series of pilot plant tests were run to compare roller press products to rod mill products in a simulated taconite flowsheet using magnet separation and closed circuit ball milling. Further investigation of a hybrid grinding system, roller press crushing followed by ball mill grinding, indicate that the combination may represent the most energy efficient system for taconite processing.

Jan 1, 1998

By L. G. Austin

The use of crushed power station slags, both natural and coated, as granules for roof shingles shows some promise. Test shingles weathered for some years showed rust spotting and granule deterioration as serious problems. Chemical analysis on a particle-by-particle basis using a scanning electron microscope-energy dispersive spectroscopy system showed the wide variability of chemical composition of the granules within a given sample. Analysis of particles acting as sources of spotting within the weathered samples showed high iron contents but no rules could he developed for predicting the long-term stability of different compositions.

Jan 1, 1990

By C. Douglas Lee

This case study describes the work done at the University of Arizona on the development of a computer mine model for an irregularly shaped and spotty ore deposit. The purpose of the work was to develop techniques for modeling any highly irregular deposit, for which the regular 3D fixed block model is not well suited. The deposit contained complex geology consisting of sedimentary beds that had been faulted, thrusted, and intruded by igneous rocks (see Fig. 1). The physical dimensions of the modeled ore body were 1067 m (3500 ft) along the N-S direction and 914 m (3000 ft) along the E-W direction. Topographic relief in the modeled area was approximately 274 m (900 ft). The highest grade of ore was found near the surface with mineralization extending down to approximately 152 m (500 ft) below. Using a fixed bench height of 12 m (40 ft), the model required 25 levels with the highest elevation being at 1286 m (4220 ft). Fig. 2 shows a cross section of the developed computer model of the ore deposit. The particular modeling approach selected for this deposit was the 3D irregular block model.* This meant that only the dimension of bench height was fixed at 12 m (40 ft). Irregular size blocks in the form of polygons were adopted in the model to describe the ore zones and geologic contacts. The following sections of this chapter describe some of the techniques used in modeling.

Jan 1, 1979

By Vathsala Rajagopal, lwao lwasaki

The grinding media materials for the mining industry require corrosion and abrasion resistance properties not only to minimize the wear but also to improve the flotation recoveries of sulfide minerals. The media wear mechanisms and the factors influencing the grinding ball wear during grinding are discussed with respect to abrasion, corrosion and impact wear of grinding media materials. Interactions between the grinding media and sulfide minerals in a ball mill adversely affect the floatabilities of the ground minerals. The possible galvanic interactions between grinding medium-mineral and their effects on the flotation responses of sulfides are also reviewed. The selection criteria for alloy composition that reduces the overall wear along with adverse effects on flotation are brought out.

Jan 1, 1992

By K. Fotoohi

This paper presents a basic, and yet practical, three-dimensional finite element model that was developed by the authors for stress/stability analysis of mine structures. While the code is linear elastic at this stage, it has some practical features that make it an attractive tool for mine design. Such features include: simulation of mine backfill support, mining induced strain energy calculation, powerful out-of-core frontal solver and failure analysis by Mohr-Coulomb or Hoek-Brown failure criteria. Model development criteria are discussed, and the potential application of the model to mining is demonstrated by design examples.

Jan 1, 1998

By L. G. Austin

Using an instrumented laboratory high-pressure grinding rolls mill, the grinding force, gap dimension, mass flow rate and net mill power were measured for six coals and a crystalline quartz. A technique was developed to estimate the compressive stress-strain curves for compression of the materials in the mill plus the effects of elastic decompression. To reconcile the mill power and grinding pressure results, it was necessary to allow for the energy recovery on decompression. No clear correlation was obtained between the form of the stress-strain curves or the variation of specific mill power factor with the Hardgrove grindability index (HGI), although coals with the lowest and highest HGIs (i.e., 44 and 106) gave results significantly different from the other coals. Feeds below 140 mesh (105 µm) flowed more rapidly than coarser feeds and would not build up high grinding pressures. This indicated shearing and fluidlike properties rather than compression as a locked bed.

Jan 1, 1998

By Alena Conrads, Markus König, Markus Scheffer, Markus Thewes, Hannah Mattern

"INTRODUCTION In recent years, the development of tunnel boring machines has revolutionized the tunneling industry. The general structure of a tunnel boring machine (TBM) can be described as a multi-component system. To achieve high performance rates, machine elements have to perform reliably. Performance losses and interruptions of the construction process should be prevented or at least, reduced to a minimum. In order to achieve high advancing rates, cutting tools must be in good condition at any time. Furthermore, failure of individual tools might result in increased and faster wear of remaining structural components. For this reason, maintaining and replacing cutting tools is crucial to prevent project delays due to insufficient boring performance. Precise prognoses concerning the prevailing geology are infeasible and thus, efficient scheduling of maintenance actions is challenging. The intention of this work is to analyze different approaches of TBM maintenance in soft ground. Different strategies are analyzed by the use of a simulation approach. Cutting tool condition is regarded as performance limiting factor. The maximum operation time of the cutting tools is determined using the “Soil Abrasivity Index”. A case study serves to show the effects of different maintenance strategies on total project duration. SCHEDULING OF MAINTENANCE ACTIONS Scheduling maintenance actions of single and multi-component systems concerns numerous fields of industrial production. Concentrating on mechanized tunneling in soft ground, cutting tool maintenance represents the most common reason for intermission of advance (Köppl 2014). In literature, time-based and condition-based maintaining techniques are widely discussed. The following section outlines the principles of time- and condition-based policies. Furthermore, examples for their applications in recent research are given. Time-Based Maintenance In general, the time-based maintenance approach assumes that the failure behavior of the system components is predictable. Maintenance actions are scheduled according to predefined intervals (e.g., hours, days, weeks). A detailed analysis of preventive repair times or interval forms the basis for maintenance decisions. For this approach, an adequate quantity and quality of data is fundamental. Numerous studies deal with the analysis of time-based maintenance for production equipment. In fields of mechanized tunneling, unplanned machine downtimes restrict the applicability of time-based maintenance approaches. Thus, this paper mainly focuses on condition-based maintenance."

Jan 1, 2016

By S. K. Kawatra, K. A. O, DeLa&apos

On-line sensors and process controls are important for efficient operation of coal preparation plants. The objective of this paper is to describe the current practice in on-line measurement of composition, density, moisture, level, flow and weight. This paper also discusses how on-line sensors can be implemented in process control, and how sensors which are currently being developed can be utilized.

Jan 1, 1988

By Ben H. Daud

A computer model has been developed at Consolidation Coal Co.'s Central Engineering Dept. for preliminary economic evaluation of deep coal mine reserves. Since it was first formulated more than two years ago, the model has been used for the following purposes: (1) ranking studies of coal exploration projects, (2) marketing surveys, (3) preliminary sale and acquisition analysis of coal reserves, and (4) parametric analysis in conjunction with detailed feasibility studies.

Jan 1, 1979

By Matthew E. Eisenmann, Gerald H. Luttrell

Performance data from phosphate plants are often untrustworthy because of difficulties associated with highly variable feeds and unstable equipment operation. In some cases, this problem is further compounded by improper sampling procedures and unreliable laboratory analyses. Questionable data often lead to misleading conclusions that result in lost productivity and profits. Data reliability may be checked using mass balances, but the mathematics associated with this procedure can be overwhelming when multiple data sets or complex circuits are evaluated. To overcome this problem, a simple spreadsheet-based mass balance program has been developed specifically for plant operators. To use this program, operators simply enter a description of their circuit and input the assay values (e.g., % BPL, % Insol, etc.) for each stream. The program then generates the best estimates of the assay values and flags values that may be unreliable. The spreadsheet is specifically designed to be easy to use and requires no knowledge of statistics or programming. This manuscript reviews the mass balance problem and describes how spreadsheet programs can be used to evaluate plant data. An example problem involving the analysis of data around a two-stage phosphate flotation circuit is presented.

Jan 1, 2002