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By M. S. Hunter, Al Bishop

In 1994, Lone Tree Mine invited Hunter Hawk to participate in a problem-solving arena at their mine located in Valmy, Nevada. Lone Tree was experiencing consistency problems with autoclave valve component quality and delivery. Based upon a prior working relationship at Homestake Mining Company's McLauglin Mine, located in Lake County, California, both customer and vendor enjoyed a measure of rap­po1i and trust - the keys to problem solving communication. This paper is an overview of the problem solving process that has contributed to Lone Tree's excellent record of 95 per cent autoclave availability since 1995.

Jan 1, 1998

By Carlos Tarazaga

Progressive Design-Build (PDB) is an emerging variation of alternative delivery programs in the underground construction industry. PDB refers to the way a construction project design is developed by the Owner and the Design-Builder in a step-by-step process. According to the Design-Build Institute of America (DBIA), Progressive Design-Build allows the design and construction team to collaborate during the earliest stages of project development. This enables engagement between the three key players in a construction contract: the owner, the designer, and the contractor. Is the PDB the best alternative program delivery for large contracts? What is the perspective of the private sector? This paper will provide an overview of the different alternative delivery programs used in the underground industry, pros and cons of each of programs, and the perspective of the designers and contractors. The paper will focus on how the PDB works, reasons why owners should consider PDB for their projects, best collaboration strategies among owners, designers, and contractors to deliver a successful project, and how to manage the project risks using a PDB method.

Jun 13, 2023

By Roland Froidevaux

The potential use of geostatistics for quantitative ore reserve reporting is shown using a simple gold case study as an example. The need of defining quantitative class limits is stressed, and a possible approach to this problem is suggested.

Jan 1, 1983

By T. Deschaines

Raman Spectroscopy has become increasingly popular as a method to rapidly identify and characterize minerals, gem stones and other inorganic materials. Raman spectroscopy provides valuable information about the chemical bonds and structure of materials. In fact, the peak locations and intensities observed in a Raman spectrum can often be used to confirm the presence or absence of particular species in a sample. Some modern Raman spectrometers have been designed to analyze samples less than a micron in size while others are designed to rapidly screen bulk material with no sample preparation. Recent advances in software and automated instrument control have greatly reduced the complexity of Raman spectral analysis and provide an easy-to-use tool for analyzing minerals. We will describe the application of several multivariate statistical analysis techniques that have been developed to make use of the spectral libraries. In these techniques the spectrum is treated as a vector and sophisticated mathematical techniques are used to determine which spectral representations in the reference library best match the spectrum from the sample. The DXR Raman microscope was used to 1) Identify minerals by spectral searching, 2) Identifying several species in a sample using multi-component analysis 3) Mapping different species in an aggregate sample and 4) identifying inclusions in a sample.

Jan 1, 2010

By A. J. Basu

A prototype expert system for planning and designing underground coal mines has been developed in a doctoral study (Basu, 1991) at the University of Kentucky (U.K.). The objective of the study was to provide a design tool for configuring layout parameters, production systems, and for determining economic feasibility. Details of knowledge engineering and the prototype knowledge-based system for integrated and intelligent planning and design have been covered in the dissertation. The prototype demonstrates its robustness by allowing interaction among major design components, most notably among ventilation, ground control, and production planning. A plan for testing and evaluating the prototype, an important phase of software development, is presented here. Existing evaluation procedures for expert system prototypes are discussed and the evaluations for the underground coal mine design expert system prototype are included. The initial testing plan used senior-level mining engineering students to test the acceptance of the prototype. This test suggested the usefulness of such a system for training and instruction. This initial acceptance test was performed with the feasibility prototype. The other test objective, i.e., testing the model's accuracy, involved extensive participation of domain experts. For overall accuracy evaluation, an existing underground coal mine design was compared with the output from a design session using the expert system prototype. The testing procedure is not an isolated, independent development phase. Much of the accuracy evaluation is done at the time of knowledge base development. Therefore, the knowledgebase itself does not need a formal test phase. The major purpose of the field testing is to determine probable user acceptance. The acceptance test determines the completeness of the prototype and also will determine efficiency of user interfaces.

Jan 1, 1992

By Charles E. Weaver

A core from the La Camelia attapulgite mine in north Florida was studied in detail to determine the detailed vertical variability and the relations of the various parameters. The structural, textural, mineralogical and chemical data indicate there are two major depositional cycles represented within the minable interval. The sediments deposited during the two cycle differ in detail but in general are similar. The environments of deposition grade from shallow marine to lagoonal to tidal flat to marsh. The sedimentary structure (lamination, burrows, pebble conglomerate), mineralogy (attapulgite, montmorillonite, sepiolite, dolomite, calcite) chemistry (Al, Mg, Fe) are closely related to each other and their nature is determined by the depositional environments. Most of the clay minerals and carbonate minerals are authigenic and are therefore particularly sensitive to environmental differences. The variability and environmental features seen in this core are characteristic of the sediments in the general attapulgite mining area. A detailed understanding of the relationships discussed should be of value in prospecting, mining and processing.

Jan 1, 1972

By Peter L. Dunn

With the advent of new high-strength magnetic materials, rare-earth magnetic separators have become more common place for processing heavy mineral sands. In many instances, rare-earth magnets have replaced conventional separators such as electromagnetic cross-belt and induced-roll type machines. This paper will present the results from a detailed test program developed to evaluate the performance of rare-earth drum and roll separators for processing heavy mineral sands. The effect of machine design parameters, such as magnetic element configuration and separator diameter, will be reviewed in light of these test results. The impact of basic operating parameters (i.e. feed rate and roll speed) on separation efficiency will also be presented.

Jan 1, 1999

By C Rutter, N Shea, K Kolobe

The Henderson mine, a panel cave mine in Colorado, has undergone multiple ventilation system changes to meet dynamic airflow needs. This paper explains the ventilation designs for different production panels, the challenges faced, and the modifications made to optimize the ventilation systems. The study highlights the importance of a robust ventilation system for safe and productive mining.

Mar 2, 2022

By A. M. Raichur

The selective adhesion of hydrophobic Mycobacterium phlei to coal particles is responsible for flocculation of fine coal from associated ash forming minerals. The driving force for the differential adhesion is the hydrophobic interactions between the fatty acid surface of the organism and hydrophobic nature of coal. The effect of Mycobacterium phlei on surface hydrophobicity, surface charge and mechanism of adhesion on coal and associated minerals are controlled by several factors including hydrophobicity and surface and solution chemistry of the system. Adhesion measurements indicate that maximum adhesion occurs below the isoelectric point (IEP) of the coal particles. While massive adhesion of Mycobacterium phlei is observed on coal, however, negligible amount of Mycobacterium phlei attaches to mineral pyrite and quartz.

Jan 1, 1995

By G. A. Hope, K. Watling, R. Woods, I. Chandra, I. M. Ritchie

This paper presents two aspects of gold leaching research and development. The first section of the paper covers the development of innovative gold leaching processes. The research in this area has concentrated on the development of new thiosulfate leaching systems which use Fe(III) stabilized by ligands as the oxidant in place of copper(II)+ammonia. The second section will cover the development of innovative techniques such as surface enhanced Raman scattering (SERS) to study the leaching of gold in cyanide solutions. It will be shown that the use of in-situ SERS yields information which cannot be obtained using other methodologies.

Jan 1, 2005

Mill #4 processes mildly refractory ore from Carlin Trend deposits. Diagnostic analysis of plant operating data was used to generate a mathematical model containing the key parameters influencing the gold recovery. The model was used to direct modifications to plant operating practice. The cyanide dosing strategy was changed to reduce preg-rob gold masses and cut reagent consumption A finer grind was achieved without capital investment. The density in CIL was lowered, and tighter control was exercised over plant throughput. These changes resulted in a recovery increase of at least 2%, worth $111,000/month at $300/oz, and concomitant reagent cost savings of $55,000/month.

Jan 1, 1999

By Thomas A. Wheeler

The reagents commercially used in coal flotation and their roles are reviewed and discussed According to their function the reagents are divided into often overlapping groups: 1. Collectors 2. Frothers 3. Conditioning Reagents Frothers have by far the largest effect on the amount of coal recovered They act not only in their traditionally accepted function of “bubble makers”, but in coal flotation they serve in a seldom acknowledged role of collectors. A lab flotation study on four samples of different coal ranks shows how these react to various frother families and proves that no froher is the optimum reagent for all types of coal. The advent of new technology in flotation equipment in the past decade has resulted in various novel designs of column cells, Jameson and Centrifloat™ cells, air-sped hydrocylones, etc. All should require special frothers or blends of frothers to meet their specific needs.

Jan 1, 1994

By Lei Zhang, P. Somasundara

The beneficiation of phosphate is complicated due to its sparingly soluble nature. The surface proper- ties of phosphate and associated minerals are determined, in addition to the ionic composition of the solution, by the dissolution of the lattice ions of the minerals and subsequent complexation, hydrolysis, adsorption, and precipitation of the dissolved species. These, in turn, are influenced by the pretreatment of the mineral. These complex interactions determine the interfacial properties of phosphate and associated minerals and thereby the efficiency of beneficiation processes such as flotation and flocculation. Under- standing of the chemistry involved in such systems is helpful to develop the optimum beneficiation schemes. It is shown that desired selectivity can be achieved by controlling the chemistry of the systems. More important, the need to conduct development tests under plant conditions is clearly demonstrated.

Jan 1, 1999

By I. S. Parrish, D. W. Kappes, G. G. Austin

Micron-sized gold disseminated in lower Cambrian siltstone has been found at the Sterling mine near Beatty, NV. A shoestring-shaped body has been developed by central and fringe drifts and is being mined via a modified retreat room and pillar system. The siliceous ore crushed to 5.08 cm (2 in ) is stacked to 4.6 m (15 ft) over a layered sand, gravel, and impervious PVC base. Gold is leached using a 0.1% cyanide solution and deposited on activated coconut shell carbon. Stripping of the carbon by hot solutions of 1% NaOH and 20% Ethanol yields overall recovery of about 75% of the fire assay head.

Jan 1, 1983

By F. Gonzalez, A. Zambrano, J. Schwoebel, S. Kravits

Significant lost time delays were experienced by Carbonifera de Nueva Rosita, S.A. de C.V. ("CNR") during mining development of the Pasta de Conchos Mine ("the Mine") near Nueva Rosita, Coahuila, Mexico. Furthermore, methane gas concentration in the return air course had exceeded 1.0 percent. Resource Enterprises, Inc. ("REI") was contracted by CNR to recommend an approach to reduce methane emissions at the Mine. In order to recommend a degasification approach, REI and CNR obtained geologic and reservoir characteristics of the Double coal seam, Olmos Formation. A vertical core hole was drilled to obtain core samples to determine gas content (average 8.4 cm3/gm) and to conduct a slug test to estimate permeability (34 md). This information was used to simulate gas productivity and drainage effectiveness. The simulation indicated that underground horizontal boreholes would remove significant quantities of gas in advance of mining in a reasonable period of time. Based on the results of the simulation study, an underground degasification drilling program was initiated at the Mine. In a six month period, five long in-mine degasification boreholes were drilled in advance of CNR's three to five years mining projections. Peak gas production from the five boreholes (approximately 2,750 cumulative meters) had exceeded 45,000 m3/D. Results to date have indicated a general reduction in methane concentration in the return air course below 0.8 percent.

Jan 1, 1993

By N. Standish

Leonard and Newman (1989) describe concepts and plans of their forthcoming project designed to increase the bulk density of broken coal at various stages of its production and handling. This is an excellent idea and something that will certainly be useful to the coal mining industry worldwide. The authors seek to achieve bulk density increase by "reducing oreliminating, through chemical additives and engineering design, particle voidage and enhance particle consolidation trickling between the point of breakage (at the face) and loading (in the shuttle car) to increase coal bulk density and productivity." In the paper, they present some supporting results of bulk density versus moisture, with or without oil addition, from the steel industry research. Unfortunately, the paper contains many misconceptions and half-truths that detract from an otherwise excellent objective of the project of increasing bulk density by reducing particle voidage -"the bottom line evaluator." Correct.

Jan 1, 1990

By Stanislaw Siewierski

One of the major problems in the exploitation of deep copper ore deposits in the Legnicko-Glogowski Copper Field is ground control and, in particular, roof control of the headings. The depth of copper deposits ranges from 600 to 1200 m. The parameters of ore-bearing rocks and the surrounding rocks show considerable variance of strength properties along the mining thickness (Fig. 1). The roof of the openings exploitation headings consists of dolomite-calciferous rocks. The roof strata consist of layers, the thickness of which vary from several centimeters to 0.6 m (sometimes to 1.0 m). These strata differ in strength and are characterized by igneous and sedimentary discontinuities. On the basis of studies in structure, properties and geological mining conditions of the roof strata in Polish copper mines, the method of roof classification has been developed. (1) This method uses the stability index "L" of the roof, calculated from [ ] The value of "t" ranges from 0, l to 0,8. Based on the value of "L", four classes of the roof (Table 1) corresponding to different degrees of fall hazard have been developed. The mining of copper ore deposit is carried out by a single lift room-and-pillar mining system or a two-stage room-and-pillar system with roof caving. (3, 4). The single lift room-and-pillar mining system is most often used. It consists in working of the deposit of 2.5 to 4.5 m mining thickness, 150-350 m long mining line, consisting of parallel room faces 6 m wide with pillars 5.7 or 16 m wide. As the mining line advances, cross-cuts joining individual rooms are made, thus forming support pillars 3x5, 7x7, 5x16, and 7x16 m (Fig. 2). The two-stage system (Fig. 3) mines the deposit with rooms 6 m wide into blocks 25 x 35 x 25 x 45 m. During the second step these pillars are worked with rooms and cross-cuts into pillars about 3 x 4 to 4 x 5 m (retreat mining). The pillars are crushed just before the fall of the roof. The maximum opening of workings in the two-step system is about 10 m, i.e. one belt entry and one row of bearing pillars. In single lift room-and-pillar systems it is about 35 m., i.e. three belt entries and three rows of bearing pillars. The support of the headings consists of expansion bolts 1.6-1.8 m installed in a bolting pattern 1.1 x 1.5 m. In both systems the fall step is about 10 m, i.e. the width of a belt and a bearing pillar. The Indications of Rock Mass Pressure Individual Dog Heading Individual dog headings are set wide apart from each other in the unmined ore deposit area where there is no interaction of headings. The indication of rock mass pressure are, in such cases, limited to the deformations and damage of side walls. Radiometric studies of rock mass loosening showed that the maximum range of lifts in side-walls immediately after web was 2 m (4,5). In the course of time the cracked side rocks fall off, thus widening the heading. The morphology of side-walls is influenced by the location of the heading in relation to clump layer/tarry. This layer is characterized by a weak strength and "lubricating" properties. The location of the heading in

Jan 1, 1982

By Cameron Dunn, Callum Fryer, Carmen Hu, Craig Sewell, Peter Stakne, Andrew Raine

The Woodsmith Project is located in north-eastern England within the North York Moors National Park. The strata contains the world’s largest known high-grade Polyhalite resource of around 2.66 billion tonnes. The Project was initiated by York Potash Limited (YPL), a subsidiary of Sirius Minerals plc., but in March 2020, a takeover was completed by Anglo American, one of the largest mining companies in the world. Polyhalite is an evaporite mineral and contains essential nutrients required for plant growth. The Polyhalite will be extracted via two deep mine shafts and transported underground from the mine site to a Materials Handling Facility on a Mineral Transport System (MTS), which comprises a high-capacity conveyor belt system located within a 4.9 m ID tunnel. In 2018, STRABAG were awarded with the design and construction of the MTS tunnel and associated infrastructure, including the high-capacity conveyor system. The scope of work consists of 300 m of open cut, 100 m SCL tunnel, 36.5 km TBM drive (originally anticipated as three separate TBM drives) along with a network of underground caverns at the Woodsmith Mine. The construction of two 380 m deep intermediate access shafts was later awarded as Amendments to the Contract. The tunnel is constructed using a Herrenknecht Single Shield TBM. As a result of how the various elements of the project have developed over time, the first TBM drive has been extended to ~29 km making it the worlds longest single heading TBM Tunnel when complete. The option of completing the entire tunnel length with a single heading TBM drive is currently being assessed by Anglo American and STRABAG. This unprecedented tunnel length requires two intermediate shafts to provide essential access and services, the first intermediate shaft is at Lockwood beck (LWB) and the second is at Ladycross (LDX). The LWB shaft has been constructed utilising the innovative Blind Boring technique never used before in the UK. This paper will explain the methodology and technical risk management associated with this technique. The authors believe that the collaborative approach between all contract partners is and continues to be the important contributor for the success of this project.

Jun 13, 2023

By Alfred W. Hefferan

A longwall face conveyor system serves the primary function as all material handling systems; i.e., to transport material between the source and its destination. However, the conveyor system must provide many other functions as opposed to the traditional belt conveyor system. In this paper, we will attempt to contrast the longwall face conveyor system with a belt conveyor system. In addition, the unique problems encountered along with the solutions to these problems will be covered. Table 1 lists the characteristics required of each conveyor system. The table demonstrates the contrast in the two systems. Both must be designed specifically to encounter its unique problems. The balance of this paper will explain how the longwall face conveyor is designed to address its requirements.

Jan 1, 2000

By LUKAS FAHLE, JURGEN F. BRUNE, ANDREW J. PETRUSKA, ELIZABETH A. HOLLEY, Gabriel Walton

Adverse ground behavior events, such as convergence and ground falls, pose critical risks to underground mine safety and productivity. Today, monitoring of such failures is primarily conducted using legacy techniques with low spatial and temporal resolution while exposing workers to hazardous environments. This study assesses the potential of novel simultaneous localization and mapping (SLAM)-based light detection and ranging (lidar) data quality for rapid, digital and, eventually, autonomous minewide underground geotechnical monitoring. We derive a comprehensive suite of quality metrics based on tests in two underground mines for two state-of-the-art mobile laser scanning (MLS) systems. Our results provide evidence that SLAM-based MLS systems provide data of the quality required to detect geotechnically relevant changes while being significantly more efficient for large mine layouts when compared to traditional static systems. Additionally, we show that SLAM-specific processing can achieve an order of magnitude better relative accuracy relevant for change detection than quality metrics derived from traditionally deployed tests would suggest, while reducing SLAM-drift error by up to 90 percent. In collaboration with an operating block-caving mine, we confirm these capabilities in field tests on a minewide scale and, for the first time, demonstrate methods of rockfall detection using MLS data. While more work is required to investigate optimal collection, processing and utilization of MLS data, we demonstrate its potential to become an effective and widely applicable data source for rapid, accurate and comprehensive geotechnical inspections.

Jan 1, 2023