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By M Rankin, F Medina, R Verburg

We conducted a preliminary assessment of an extensive deposit of historic tailings discharged over a period of 40 years to the shoreline along a Southern Peruvian coastline. The tailings formed an extensive beach approximately 2.4 km long and 300 m wide. The tailings consist principally of pyrite (37 to 59 per cent), hematite (nine to 20 per cent), magnetite (three to 13 per cent) and quartz (11 to 36 per cent). The present operating company was required to evaluate the feasibility of capping the ocean side tailings deposit, however, given the size of the undertaking and the potential to reclaim residual minerals from the tailings, it was prudent to first evaluate whether capping would in fact reduce the impacts to the marine environment. Therefore this preliminary assessment examined: 1. metals contamination in tailings, shoreline porewater and marine sediments; 2. reactivity of tailings and acid generation potential; and 3. the potential for biological effects from metal contamination in the uplands tailings (solid phase) and beach porewater. Based on mineralogy, column leach studies and chemical results, the upland tailings have a high geochemical potential to acidify and release metals, especially copper, nickel and zinc, should they be subject to oxygenated and aqueous conditions. But, the extreme arid climate results in very low potential for precipitation and virtually precludes the transport of acid drainage reaction products from the upland tailings towards ocean. Wind erosion caused by offshore winds is likely a small source of tailing transport to the ocean. Since some potential exists to reprocess the tailings in the future, capping does not seem justified at present.

Jan 1, 2003

By Richard D. Call

Predicting the performance of a waste embankment requires an estimate of the properties of the waste and foundation materials. The performance characteristics and the associated material properties are: [ ] Methods for obtaining estimates of the material properties include: laboratory and field testing, back analysis, and indirect estimates from other material properties. The most critical technical need is the development of indirect methods for use in feasibility studies and mine planning, prior to production when actual samples of waste material are not available. Material properties are not unique, single values; they are probability distributions. There are two components to these distributions: the uncertainties in testing and the inherent variability of the material. The objectives of a material properties evaluation should be to obtain an unbiased estimate of the property distributions rather than the average or the minimum value. Whether the current trend to a probability design analysis is followed or a simple sensitivity analysis is conducted, the unbiased probability distribution is preferable to single values.

Jan 1, 1985

By Marshall T. E, Finfinger G. L

Gulf Coast domal salt mining operations have had sporadic encounters with methane gas emitted without any warning. In virtually all confirmed cases, the methane was localized in methane enriched zones. In a few cases large quantities of methane were expelled rapidly with salt outbursts, resulting in dangerous methane concentrations. Estimates of methane liberated by face blasts in methane-enriched areas is needed in determining how much air should be supplied to the face for proper dilution. A relationship between the gas content of salt samples collected from the face and the amount of methane liberated would be helpful in estimating how much methane will be produced by a face blast. Little is known about the layering or stratification of methane in large area-low velocity airways. This publication reports on three tests conducted by the Bureau of Mines which monitored the immediate return air of four faces during blasting. The test locations were in a methane gas-enriched section that had previously experienced two large outbursts and many smaller ones. A comparison was made between gas content values of face salt samples from the dissolution test and the gas liberation quantities. The characteristic movements of the methane in a large room with low air velocities were charted. This will help to better understand the factors involved in proper placement of methane sensors as a warning system.

Jan 1, 1988

By J. A. Organiscak

This paper examines methods for limiting occupational silica exposures for roof-bolting personnel in underground coal mining. A canopy air curtain and an air tube were evaluated as means to provide filtered air over the breathing zone of these personnel. Laboratory testing showed that dust reductions beneath the air curtain and air tube approached 60% and 40%, respectively, with low interference air velocities. The data also showed that dust reductions were highest for positions closest to the device and that these levels decreased with distance. This paper also evaluates a metal rake, a flexible insert and a rigid insert for cleaning the roof-bolter dust collector box. Less dust was produced when using the rigid insert. Surprisingly, the flexible insert was sometimes no better than scraping or raking the dust onto the mine floor. However, little dust got on the workers coveralls when using either of the inserts.

Jan 1, 2003

By S. T. L. Harrison, J. R. Amaral Filho, M. Smart, J. Broadhurst, J. Weiler

Technosol production from mine waste, following amendment with additional organic residues, to provide healthy and functional topsoil is an advantageous alternative to the long-term dump disposal of mine waste. Minimising the legacy of mine waste and supplying soil for mine site rehabilitation contributes towards more sustainable mining practices. Following the creation of the physicochemical structure of the soil from appropriate mixtures of coal waste with low sulfur content, physical ameliorants and nutrient sources, the inoculation of Technosols with active microbial suspensions may accelerate the decomposition of organic matter present and ensure nutrient availability for plant growth through active nutrient cycling, particularly of nitrogen, sulfur and phosphorous. In this paper, South African ultrafine coal waste was used as the main mineral matrix, and malt residue was used as source of organic matter and nutrients. In order to evaluate the effects of Technosol inoculation, five microbial treatments were used, including the addition of: commercial grade efficient microorganisms (EM Prosoil), anaerobic digested sludge supernatant from treating brewery waste, and ‘tea’ extracts prepared from compost, vermicompost and soil native to the mining area. Growth experiments were carried out using Eragrostis teff, commonly known as teff, a grass typically used for the rehabilitation of mined areas in South Africa. Preliminary results showed that Technosols inoculated with microorganisms performed better in terms of nutrient availability and plant growth. Varied performance was observed as a function of the microbial inoculation applied. This suggests that the inoculation of Technosols with appropriate microorganisms may be recommended to accelerate nutrient availability assisting plant growth during the initial establishing of the Technosols. Technosols continue to show promise as an alternative to both mine waste disposal and the burrowing of topsoils for mine rehabilitation. Keywords: Fabricated soil, mine waste, coal discards, malt residue, nutrient availability, soil microbiology, plant growth

Jan 1, 2020

By W. S. Hui, M. G. Silva-Valenzuela, H. Wiebeck, F. R. Valenzuela-Diaz, B. B. Michel

Biodegradable polymer microcapsules have been used as a control sustained release system with many applications. Studies reveal that the incorporation of nanoparticles improves matrix properties, even more so if the clay is modified. The objective of this work was to compare microcapsules of poly (succinate-co-butylenelactate) (PBSL) reinforced with Brazilian clay, composed of smectites and kaolinite, in its natural (MMT/K) and modified (O-MMT/K) forms. Nanocomposites and microcapsules were synthesized by emulsification-diffusion of solvent and solvent diffusion methods. Its characterization was then performed by scanning electron microscopy (SEM), stereo microscopy and wide-angle X-ray diffraction (XRD). The results reported corroborate that PBSL/OMMT-K form an intercalated montmorillonite and kaolinite nanostructure, capable of generating uniform spherical microcapsules with diameter values smaller than that of PBSL/MMT-K, reaching 5–10 lm. DRX indicates that there was a real change in the clay structure. The incorporation of modified clay showed an improvement in surface quality and the strength of microcapsules, making it possible to produce smaller sizes.

Mar 1, 2018

By S. A. Braley

DRAINAGE water from coal mines is probably the most serious water pollution problem today, varying in importance according to location of the mines and geological structure. Drainage may be either acid or alkaline in character. Acid discharge, the most severely detrimental to a stream, is caused by natural oxidation of the sulfuritic material (FeS2) in the strata associated with the coal seam. Since the acid is the result of a natural reaction the acid water differs because it does not cease with abandonment of the mining operations. There is no known economical method of neutralizing acid mine water or any practical method to prevent oxidation of exposed pyrite. Since production of acid from a mine does not stop when mining stops, the total quantity produced depends entirely upon the excavated areas. The increasing volume of acid water in many mines has greatly increased operating costs. Pumping is expensive and acid mine waters are destructive of all equipment, especially metals in pumps and piping, and necessitate the use of corrosion-resistant materials. Discharge of the acid mine drainage into streams neutralizes their normal alkalinity, causes them to become acid, and produces an environment unfavorable for aquatic life and unsuited for industrial or domestic use without costly treatment.

Jan 1, 1957

By V. Gangrade, J. Addis, S. Vanderslice

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are conducting research to improve the ventilation of large-opening underground stone mines. The mine ventilation in these mines are characterized by: (1) challenges related to keeping airflow velocities high enough to effectively remove or dilute airborne contaminants, (2) low pressure losses needed to move large air volumes of air, and (3) costly stoppings needed to direct ventilation airflows. Each of two field studies was dedicated to specific focus areas. The first focus area was the characterization of underground mine ventilation airflow. The primary means of airflow control in stone mines is through the use of freestanding booster fans. The primary goal of this study was to identify the effectiveness of various fan types and optimize their placement. Both traverse and grid-based airflow readings were taken at various distances from the fans, ranging from 70 ft to 425 ft away from the fan. The air readings were taken using a vane-anemometer and a handheld hotwire anemometer. The data was used to develop precise computational fluid dynamics models. The second focus area was to determine diesel particulate matter (DPM) concentrations in the mine. For large-opening underground stone mines, controlling DPM exposures dictates the design of the ventilation system. Therefore, researchers carried out the DPM sampling campaign to identify potential areas of concern within the mine. The samples collected during the campaign were analyzed using NIOSH Method 5040. The sampling was done using the Mine Safety and Health Administration’s (MSHA) compliance sampling methodology.

Feb 1, 2023

By W. David Menzie

An inventory of the mineral resources of a region is a most desirable basis for planning their systematic development. In the absence of appropriate samples upon which to base a reliable estimate of this inventory, investigators have resorted to a number of indirect approaches; the unit regional value concept forms the basis for one such approach. The produced resources of a region are a function of the inventory multiplied by the degree of intensity (some fraction between zero and one) of development of the resources. A convenient means of expressing this amount is to accumulate the weight and value of resource and to prorate the totals over the area represented by the unit sampled; i.e., weight and value per unit area or tonnes/km.2 and U.S. 1967 $/km.2. When this approach is used for the U.S.A., South Africa and Rhodesia the average value of (log.) U.S. 67$/km.2 for the states of the U.S.A. and South Africa are similar ($55,176 U.S.$67/km.2 and $52,538/km.2 respectively); whereas, Rhodesia is relatively underdeveloped (10,301 U.S.67$/km.2). On the other hand if the individual commodities are used as a basis for comparison, the U.S.A. shows the greatest diversity (67 commodities out of a possible total of 75) with South Africa next (50 commodities) and Rhodesia last with only 26 commodities. Since it is known that area and value are not simply related perhaps diversity is directly related to area. Again the kinds of commodities which have contributed the greatest value to the totals differs, with fuels (petroleum, coal and natural gas) predominating in the U.S.A. totals; whereas, South Africa and Rhodesia obtain their greatest contributions from gold, diamonds (S. Africa) coal and asbestos. In each case the greatest value of resources is produced from sedimentary rocks. As a somewhat different kind of example, consider a single resource (petroleum, the most valuable in the U.S.A.) over a large area (number of sampling units) the U.S.A. by state. Furthermore, assume that the model frequency distribution of the amount of petroleum (tonnes/km.2) is log normal. Then the present production fails to match the model first because 17 states (34% out of 50) have not produced petroleum. Of the remaining 33 states, Louisiana has produced the most (15,177 tonnes/km.2) and the frequency histogram is still skew. A spatial analysis of the distribution of the amount of petroleum by state shows that the samples (i.e., states) are not random; the non-producers and producers tend to cluster. It remains to be seen if this is indeed a true representation of the incidence of petroleum or is a function of the exploration philosophy currently in vogue.

Jan 1, 1977

By Augustus Locke

I WISH to urge on this Committee the task of evaluating mining geology. -My motive is as follows: It, is a. duty of the Institute from time to5 time, to establish the social perspective of the professions grouped within it, not simply to promote their use, but to determine with engineering definiteness their true powers and functions. This becomes the delegated duty, therefore, of this committee in respect to geology. Be- cause my own subject is mining, I shall confine my remarks to mining geology. But I believe that the evaluation should be made to include all of that geology termed economic. The perspective for such evaluation is shown in the nature of the public support given to geology. The federal Geological Survey, the leading organization on the economic side, is actuated by the zeal of a small group of devoted professionals who consider its work valuable, ' It proceeds, however, on a starvation ration of appropriations, and that implies that neither the corporations, the voters nor the vote getters consider it important. Altogether, in' the public consciousness, geology is negligible. That, at the same moment, .the profession should act with full confidence, while everyone else should act' with opposite motives, is not fitting. For us, as a committee, to remain incurious regarding such a disparity of beliefs is quite impossible.

Jan 1, 1931

By Jan M. Mutmansky

Since 1973 when the first edition of the SME Mining Engineering Handbook was published, many significant changes have occurred in the US mining industry. The industry went through a fairly prosperous period immediately after 1973, but then many economic pressures came to bear on mining companies, particularly in the metal and coal branches of the industry. These pressures changed both the mining methods used and the general economics of the mining methods. As a result, the industry today is different in many ways titan it was in 1973. A general summary of some of the more important changes that have come about will be provided here as well as some assessment of the effects of these changes on the choices of mining methods. In the metal mining industry, the most significant trends were increased surface mining, the use of larger and more efficient equipment, and increased technology and automation. The primary impetus for these changes was unprecedented competition from foreign producers. In many cases, this competition came about because of the nationalization of foreign mines and the tendency for these mines to become a source of foreign exchange. Under these circumstances, the mines could be operated even though they were not profitable. As a result, domestic

Jan 1, 2008

By Onur Golbası, Berk Gokce

Investment decisions in the mining industry are complicated by sector-specific uncertainties. This study presents a multi-submodule system dynamics model to capture the dynamic complexities of decision-making across mineral property development stages. The model includes five interconnected subsystems: valuation, production, growth strategy, demand, and finance. Developed through system decomposition, expert input, and literature, the model is tested on a hypothetical copper mine with 850 ktpa capacity and 1% cu grade. Simulated over five years with quarterly steps, it estimates an enterprise value of $78.9 million and a target growth rate of 11.2%. Results highlight the significant effects of operating costs, capital policies, and inflation on free cash flow, and the critical role of mineral reserves in sustaining growth. This model supports strategic investment analysis across different minerals and development phases, offering mining investors a robust tool for optimizing decisions.

Feb 22, 2026

By Robert Bissonette, Samir Sbai

A critical component of implementing autonomous systems is the ability to use information from a robust sensory and information system to make sound, predictable, and repeatable decisions to assure safety. This means that any such system would need to evaluate what objects (people, equipment, boulders, etc.) of interest exist in that environment (with relevant data about identity, trajectory, characteristics, etc.), project a future continuum of those objects (including considerations for variabilities), and make control intervention choices to minimize risk due to exposures in the present operational area. The components of an overall system would include: a) sensor and data fusion, b) probability projection of future states, c) generation and evaluation of alternate futures, and d) implementation of best course of action to reduce risk. The National Institute for Occupational Safety and Health (NIOSH) Spokane Mining Research Division (SMRD) is studying this framework for applications for autonomous mining equipment. This paper focuses on using information from the sensor fusion engine to generate a continuous projection of future and alternate states (b and c above) incorporating the factors of confidence, accuracy, tolerance, and other variabilities. We refer to this as Machine Situational Awareness (MSA).

Jun 25, 2023

By S. E. Phillipson

The MSHA Technical Support, Roof Control Division's primary evaluation tool for coal pillar designs is the Analysis of Coal Pillar Stability (ACPS) program. However, ACPS is limited to evaluating interactions between two seams at a time, which is not ideal for complex multiple- seam scenarios. Further, it does not recognize the influence of strata properties in the interburden and cannot be used to evaluate individual pillars. We apply the Rocscience RS2 two-dimensional finite element program as a complement to ACPS. Complex multiple-seam scenarios can be characterized by a modified pillar stability factor where the ACPS single-seam development pillar stability factor is multiplied by the ratio of average single-seam development stress to the stress in the critical pillar at the multiple-seam stage, using the values of o as predicted by RS2. Several series of test examples involving two-seam analyses with isolated remnants, gob-solid boundaries, and high extraction areas of varying width were used to calibrate simulated gob properties such that the ACPS+RS2 method generated results that matched a traditional ACPS Stability Factor to within 13%. As high-extraction areas become wider and deeper, progressively stiffer gob is simulated by increasing the Young's Modulus property in RS2. After achieving calibration with the test series, three examples of complex multiple-seam scenarios were evaluated, using reasonable properties for strata types and thicknesses based on core log data. Resulting modified stability factors are reasonably close to those predicted by ACPS, although affected by units of sandstone in the interburden and gob shadows superimposed on remnant structures. This tends to show that even in complex multiple-seam conditions, applying ACPS to the worst-case interaction should usually result in an acceptable pillar design.

Jun 25, 2024

"Mining of ore bodies that are located at great depths enforces long distances to move the excavated rock masses to the surface. The excavated rock mass contains not only ore that can be economically extracted from the face but also waste, which is usually discarded several steps further downstream in the process. As a result, a large amount of rock is transported to the surface, influencing the costs at which the ore is produced. Reducing the amount of waste rock being transported to the surface by introducing a near-to-face sorting plant would improve the in many cases strained transport system in the deep mine. In this study, one of Boliden’s cut-and-fill mines was analysed with respect to the challenges related to rock transportation and increasing mining depth. The study aims to evaluate the potential use of a new near-to-face sorting system in the operating underground mine. Discrete event simulation was used to study and analyse the rock transportation system with and without the near-to-face sorting plant. The paper shows how the underground rock transportation system and the production were influenced when the near-to-face sorting equipment was added into the current system. INTRODUCTION The locations of waste rejection in the mining processes and the cost of removing waste from the system compared with the cost and energy necessary for further comminution are important parts in the material handling system (Bowman and Bearman, 2014). In an underground mine, longer material transportation distances generate the need for further investment in the mobile fleet and ancillary equipment in order to reduce the waste from the material handling as early as possible. One of the ways of reducing the waste (coarse particle size) in material handling is by use of pre-concentration. The benefits of pre-concentration are well known (Schena et al. 1990; Feasby, 1995; Peters et al. 1999; Klein et al. 2002), as well as the factors governing the feasibility of underground pre-concentration (Peters et al., 1999) and the mining integration issues (Klein et al. 2003). In the Onaping Depth orebody in Sudbury, Ontario the study of implementing the pre-concentration resulted in increased capital costs of 6% and a reduction in the operating costs of between 20-40% (Bamber et al, 2004). In this paper, the effects on the production and the transportation system of implementing underground pre-concentration by means of a near-to-face ore sorting plant in the Kristineberg mine are modeled and analyzed using the AutoMod tool. This tool is based on discrete event simulation (DES) (Banks, 2004), allowing high flexibility in customization and enabling the user to view the production of the system before ore sorting plant integration. The sorting plant selected in the simulation is built from modules. The material is fed by conveyor and goes through the comminution, classification, sorting and service processes after which the waste is redirected to backfill headings via trucks. The system mechanically ejects the particles from the feed stream on the basis of the information obtained from both the XRT sensor’s signal and 3D laser scanner based on both density and rate of refraction of light within a particular mineral. The sorting plant could pre-concentrate the metal ore up to 300 mm size. The plant requires little auxiliary infrastructure, is easily modularized for underground installation and can be easily relocated to different areas."

Jan 1, 2016

By D. A. Cowen

Toll and custom treatment of base metal concentrates have been performed for decades as mines and concentrators are developed distant from capital and, energy-intensive smelting and refining facilities. Commercial treatment terms have been developed and refined for over a century, and are negotiated taking into account a complex array of quality and economic factors. Treatment of third-party concentrates in the South African platinum industry is a comparatively recent development, brought about by the opening up of mineral rights and operations being developed that are smaller than the critical size required to sustain capitalization of smelting or refining plant. Published commercial terms have not been demonstrated to reflect the complexities and subtleties of base metal concentrate markets. This paper outlines some key elements and parameter ranges of base metal concentrate treatment contracts, and applies similar principles to typical Merensky and UG2 platinum group element (PGE) concentrates to determine potential value distribution between the mining and treatment parties in tolling arrangements.

Jan 1, 2012

By S. Q. Zhu

A newly developed coal flotation collector ZFC and its flotation characteristics for five different coals were introduced in this paper. ZFC is an emulsion composed of 27% diesel oil, 70% water and 3% surfactants. The main surfactant is synthesized with oil which is environmental favorable and reproducible. Compared flotation experiments show that, at the same dosage, ZFC give 2%~5% recovery promotion than typical collector with only a slightly ash content increment, but saving 70% diesel oil. Zeta-potential and Wetting heat measurement indicate that the surfactant helps the interactions between oil and coal particles, the industrial application tests in several coal preparation plants demonstrate that ZFC is suitable both in technical and economical aspects.

Jan 1, 2014

By Bernhard Schwab

A popular rule in the mining industry is that a property should only be developed if average unit production cost is less than a given proportion of the estimated long-run price of the mineral. This paper provides a comparative analysis of the average cost approach (ACA) with the use of net present value (NPV) as an investment criterion. It is concluded that the ACA is an easily understood and easily applied rule of thumb which may serve as a rough first screening device, for example in the early stages of deposit exploration. Its operational convenience is at the expense of accuracy and validity, and the NPV provides a sounder method of making decisions, especially in the case of marginal deposits.

Jan 1, 1978

By Akira Yazawa

In the field of pyrometallurgy, the equilibrium evaluation has recently become easy by use of thermodynamic software, but it is strongly desired to estimate the amounts of non-equilibrium minor components to simulate practical processes. However, simple physico-chemical technique can not be applied to evaluate practical non-equilibrium components for many reasons. As an engineering solution for postulated equilibrium system, the activity coefficient is modified and introduced as the simulation parameter referred to as the "adjustment coefficient." This modified thermodynamic calculations were adopted to various sulfide roasting processes where many solid phases are participating and the system is not necessarily in equilibrium. Successful simulation was realized by assigning suitable adjustment coefficients for minor components which form a pseudo solid solution in the calcine. Some examples from sulfation roasting and dearsenizing roasting were discussed. In the smelting system, the loss of copper in slag is caused by equilibrium and non- equilibrium reasons, that is, chemical dissolution and entrainment of copper in slag. The total copper content of slag was simulated by use of the adjustment coefficient for entrained copper.

Jan 1, 1998

By N. ?peh

The purpose of the paper is to present a way of assessing nonrenewable lignite resources by means of sustainability indicators. An introductory presentation of the origin and characteristics of the discussed nonrenewable natural resources is followed by the study and analysis of separate sustainability indicators. Out of many, only the ones that would directly relate to the explored coal deposit were studied. Some different viewpoints such as economic, social and environmental were assessed inside the studied landscape structure and in relation to other provincial resources using the indicators that are closely linked with the explored lignite reserves. Exploitation of coal as an underground nonrenewable natural resource, has been taking place in the ?alek valley for more than 120 years. However, about 60% of the coal will still be left underground since not all coal will have been extracted when the mine closes. According to the regional and wider national strategic goals concerning the use of natural resources and electricity production in the future, the sustainable aspect of the exploitation of the geologically well explored reserves is emphasized in the paper. Finally, we have tried to evaluate the role and the meaning of the studied underground natural resources for further sustainable development of the ?alek valley and placed stress on the most questionable spheres that should be considered preferentially.

Jan 1, 2007