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By Daniel Hodouin

Artificial neural networks (ANN) are of growing interest in a wide variety of applications. Pattern recognition, speech processing, financial analysis, signal processing and process control are at present the most successful ones. This paper is an attempt to illustrate the potentiality of ANN applied to mineral processing. An introduction to the technology of ANN is first proposed to describe the various components and to explain the various phases encountered in setting up a network. Then examples are given to illustrate the use of ANN dynamic modelling of mineral processing units or plants and in process control.

Jan 1, 1991

By C. J. Pritchard, R. D. Jacksha, K. V. Raj, C. B. Sunderman

In underground metal/nonmetal mines, repeated localized short-term exposure to high levels of airborne contaminants can become a serious health issue. Currently, there are no common mechanisms to control or mitigate these short-term high exposures to contaminants. To improve miners’ health and safety, the U.S. National Institute for Occupational Safety and Health’s Spokane Mining Research Division (SMRD) is developing a smart monitoring and control (SMAC) system for the real-time monitoring of mine air quality, with integrated countermeasures to reduce high concentrations of airborne contaminants in localized sections of mines. To develop and test a SMAC system capable of being implemented in an underground mine, SMRD researchers built a test apparatus incorporating a fan, louver, ducting and sensors combined with atmospheric monitoring and control software. This system will institute effective countermeasures to reduce contaminant levels, improving miner safety and health.

Jan 1, 2018

By R. Mensah-Biney

The kinetics of loading of gold from bromide solution onto an anion exchange resin, PAZ-4, were investigated in a batch stirred reactor. The initial loading rate was described mathematically by a first-order reaction rate equation. The effect of agitation speed, temperature, resin particle size, resin concentration, initial concentration of gold and bromine in solution on the rate was investigated. The model described fairly accurately the loading process in terms of the variables investigated. The rate constant for the initial loading ranged from 0.5 to 1.3 x10-3 sec-1 and the half-time was 9.3 to 56 minutes. The initial rate constant increased with increasing temperature with an activation energy of 15.7 kJ/mole (3.8 kcal/mole). The rate constant was directly proportional to the concentration of the resin in solution. The subsequent reduction reaction was also modeled by the first-order rate equation and the apparent rate constant was estimated to be 3.0 x 10-6 sec-1 with a half-time of about 44 hours.

Jan 1, 1994

By Fathi Habashi

OXIDE ORES can be divided into two groups: 1) Simple oxides (Table 3.1). 2) Complex oxides. Those ores containing minerals composed of two oxides; an acid oxide (Cr2O3, Nb2O5, etc.), and a basic oxide (CaO, FeO, MnO), as shown in Table 3.2.

Jan 1, 1970

By Ratnakar Singh, Raj Kishore, Kisor Kumar Sahu, Ranjeet Kumar Singh, Ganesh Chalavadi

The Falcon concentrator is capable of separating minerals in fine size classes based on their differential density. Separation of mineral particles depends upon the fluid flow characteristics and relative movement of particles in a fluid. In the present study, a fluid flow characteristic inside the Falcon concentrator was established through experimentation and modeling. The Falcon concentrator has two fluid entry points: (a) Fluid entering through gravity assisted feeding system and (b) Fluid entering through the fluidized hole on the concentrator wall. In order to identify the role of fluid entering the concentrator, a tracer was injected into the system. As per the tracer based experimentation, it was established that fluid entering through the gravity based feeding system is responsible for thin flowing film formation in the stratification zone where particles are stratified based on their relative density. The momentum balance and continuity equations were simplified for a high centrifugal force field, and the fluid velocity profile was estimated inside the thin flowing film. Estimated fluid flow profiles will help to simulate the particle trajectories inside the Falcon concentrator. The influence of rotational speed, fluid flow rate, and cone angle on the fluid velocity profile were investigated. Fluid thickness over the concentrator wall is also estimated, and it is typically of the order of ~150–200 μm.

By Y. David

In 1990, the United States became only the second country (after China) to produce more than 900 Mt (1 billion st) of coal in a single year. US production of bituminous and subbituminous coal, lignite and anthracite totaled 933.5 Mt (1.029 billion st) in 1990, 5% more than in 1989. The production gains were largely due to the rebuilding of depleted coal stockpiles by electric utilities and a surge in US coal exports. Domestic coal consumption essentially remained at its 1989 level. A slight increase in electric utility coal consumption was partly offset by a decline in metallurgical coal use. The use of coal in other industries and in the residential-commercial sector remained virtually flat.

Jan 1, 1991

By Nader Shahcheraghi, Verya Nasri, Mehdi Bakhshi, Ali Haghighat

An accidental fire load is one of the major loads considered in design of segmental linings in transit tunnel. Typically, a two-dimensional coupled thermo-mechanical finite element analysis (FEA) is conducted. The conventional approach involves using standard fire curves (temperature-time curves) which can lead to a significant overestimation of fire load and tunnel lining thickness in metro tunnels. The focus of this paper is on the cutting-edge approach, using 3D computational fluid dynamics (CFD) analysis of real train fires in metro tunnels and coupled thermo-mechanical finite element analysis (FEA) to accurately and cost-effectively design fiber-reinforced concrete (FRC) segmental tunnel linings for large-scale metro projects.

Jun 23, 2024

By B. P. Atkin, D. W. Brown

The handleability monitor has been specifically designed to provide a simple, rapid and on-site assessment of the whole or part consignment of a coal blend in its ‘as-received’ condition. Evaluation has been carried out at a number of coal-handling plants, on both metallurgical and power station coals from a variety of sources world-wide. The results which are used to predict which coals could routinely pass through a handling plant at line capacity, without causing blockage or delay, have also been correlated with moisture, ash and size analyses of the coal to develop a predictive model of handleability.

Jan 1, 2000

By L. A. Ruth

Introduction The US Department of Energy's Office of Fossil Energy has begun a new approach for developing the ultra-clean energy plants. This approach will allow the nation to continue to use low-cost fossil fuel feedstocks during the early decades of the 21st century. The new approach is called Vision 21. The overall goal is to effectively eliminate, at competitive costs, environmental concerns associated with the use of fossil fuels for producing electricity and transportation fuels. Vision 21 is based on the following three premises: •The nation will need to rely on fossil fuels for a major share of our energy needs well into the 21st century. •It makes good sense to rely on a diverse mix of energy resources, including coal, gas,

Jan 1, 2003

By Donald J. Worth

When Eugene Bailey asked me to contribute to this session on "Canadian exploration - 1976", it took a little coaxing before he got me to agree. My immediate reaction was, what could i say about Canadian exploration that already had not been said a hundred times in the past few years; secondly, why include a banking person in such a discussion? Everyone knows banks only come into the picture after the discovery has been made and feasibility well established and validated. Rather than wrestle with these misgivings, I decided to take the easy way out and go on blind faith in Eugene - that is, he asked me so he must think that I could come up with some useful thoughts and at least touch upon some of the pros and cons of exploration in Canada. The object of the whole exploration exercise is to Find economic deposits, once they are found, one cannot really move them elsewhere to mine them. It follows, therefore, that we should really be speaking about the pros and cons of mining In Canada and my treatise will eventually lean in this direction. In any event and before getting down to the pros and cons, let us take a quick look at the history of mineral resource development in our country since the end of world war II. At that time, we were producing well under one billion dollars worth of mineral products including hydrocarbons.

Jan 1, 1976

By C. Duke

The water treatment industry has historically been involved with reducing or inhibiting the inherant scale forming or fouling tendencies of natural waters associated with large industrial cooling water systems. Fouling is an extremely complex phenomenon. From a fundamental point of view, it may be characterized as a combined momentum, heat, and mass transfer problem. Chemical reaction kinetics is involved, as well as the solubility characteristics of salts in water and corrosion technology. It is a routine practice to over size pumps, piping and heat exchangers to compensate for fouling.

Jan 1, 1983

By Robert H. Merrill

INTRODUCTION In most cases, the design of an underground mine is based upon the premise that the ground either will cave or will be stable. This chapter concerns the design of a mine in ground that will cave readily or with some as¬sistance, such as by long-hole drilling and blasting. Some of the more widely used caving systems of mining are panel caving, block caving, sublevel caving, and large pillar recovery. Some of the less widely used systems are glory-hole, top slicing, and induction caving. Al¬though the common practice of pillar robbing is not usually considered to be a caving system, this subject will be treated as a part of this chapter. BASICS OF CAVING Caving systems are most successful in ground that will cave in sizes that will flow through openings and grizzlies, and will easily load in cars or on belts for haul¬age. The ground most likely to cave well is highly frac¬tured and contains breaks, flaws, or other discontinui¬ties that form planes of weakness. Also, caving action can be greatly enhanced if the host rock itself is low in compressive, shear, and tensile strength. Ideally, a cav¬ing system of mining is best employed when the criteria for caving is a feature of the ore body and the develop¬ment drifts, haulageways, and drawpoints can be mined in a highly competent rock beneath the mineralized zone. However, the development is often in the same, or similar, fractured rock and the openings require sub¬stantial artificial support to assure stability. Several clues can be assembled to identify potential caving ground; however, for borderline cases, no sure method has been devised to date. The diamond-drill cores taken for exploration can provide an excellent clue provided drilling is performed carefully by experienced drillers. For example, if the ground is cored in such a manner that the breaks in the core are caused more by failure of the rock than by whipping core barrels, plugged drill bits, or other drilling causes, and the intact core lengths are consistently long [say, 0.6 to 3 m (2 to 10 ft) of unbroken core], there is little reason to believe the ground will cave without considerable as¬sistance. This is especially true for rocks with compres¬sive strengths above 34.5 MPa (5000 psi) and tensile strengths above 2.1 MPa (300 psi). On the other hand, if core recovery is low (below 80%) and the recovered ore is broken in small pieces and the breaks are along obvious weaknesses in the rock, the chances are excel¬lent that the ground will cave. This is true even when the rock between the defects has high compressive and tensile strength. Another clue has already been mentioned, that is, the measurement of the physical properties of the rock and the natural planes of weakness or defects in the rock. The planes of weakness in the rock can often be detected from outcrops, cores, or other exposures of the rock under consideration. Some rock types are known to be strong and will sustain large, unsupported open¬ings and would be difficult to cave intentionally. Yet the same rock type can also contain unbonded or weak planes of weakness or fractures, and in these locations the rock would undoubtedly cave with little assistance. Therefore, although the inherent strength of the rock is a factor in caving, the natural defects in the rock are more often the deciding factor. DESIGN CONCEPTS For the most part, the design of openings for caving ground is a problem of the interaction of openings over a relatively large area of the mine. To illustrate, Fig. 1 is a simplified section of a series of openings along the grizzly level or draw level of a block caving or panel caving development, and above this opening is a simpli¬fied section of a room-and-pillar arrangement on the undercut level. At this stage of the development, the stresses around the openings on the grizzly level are only moderately influenced by the openings on the undercut level and vice versa. Therefore, the stresses around the openings are approximated by the stresses around single or multiple openings in rock, the values of which are de¬scribed in the literature (Obert, Duvall, and Merrill, 1960; Obert and Duvall, 1967). Once the pillars on the undercut level are blasted (Fig. 2), the situation changes abruptly. The undercut opening (prior to caving) now can be approximated as an ovaloidal opening above the grizzly drifts and this opening tends to shield the vertical stress field. As the caved stage is drawn the stope approximates a much larger rectangular or square opening filled with rock, and if the rock is not sustaining a major portion of the stress field, this opening can be considered (for en¬gineering purposes) to be empty and the stresses that interact between the larger and the smaller openings take on a totally new perspective (see Fig. 3). Next, let the material cave to the surface, and let the caving ma¬terial sustain some stress, but much less than if the ma¬terial were intact. This condition is similar to a soft inclusion in a rigid body and has been treated in the literature (for example, Donnell, 1941). At this point in time, the grizzly drifts are subjected to the stress con-

Jan 1, 1982

By M. C. Rockwell

There are approximately 1,800,000 t of discarded dolomitic-limestone tailings from the Gays River lead/zinc mining operation in Nova Scotia. Neutralization effectiveness similar to an agricultural grade limestone and low contents of residual metals make the tailings a suitable source' of soil conditioner material for the local market. However, the fine particle size, 98% passing 147µm, and a high moisture content make their handling and application difficult. Agglomeration of the tailings into relatively small hard pellets was investigated and difficul¬ties were overcome. Pellets with a range of pH values and various amounts of soil nutrients and moisture content less than 10% were obtained, from tailings containing 20% initial moisture, through the addition of less than 15% selected materials.

Jan 1, 1985

By D. R. East

Recent experiences within certain sectors of the international mining industry suggest an underestimation of the environmental risks associated with the design of mine waste-management facilities. These experiences show that the technical and managerial challenges of responsible mine waste management is not always fully appreciated. Unfortunately, the image of the mining industry's environmental performance is negatively impacted by a relatively few number of failures. This negative view overrides the many positive contributions made by the majority of mining companies. The fact that these failures continue to occur in developed and developing countries is indeed re¬markable and indicates a degree of risk-taking approaching unacceptable levels. The design requirements for tailings storage facilities are, in many cases, more demanding than those of conventional water dams because seepage of fluids that contain dissolved metals may pose a greater threat than the mere loss of water.

Jan 1, 2000

By Andrew J. Petruska, Austin F. Oltmanns

The paper proposes a capacitive load cell for detecting changes in material and tool wear conditions for conical picks used in underground mining. The current process is dangerous and subjective, relying on human operators near the cutting interface. The new sensor aims to improve worker safety by allowing operators to perform their functions from a greater distance.

Aug 1, 2023

By S. S. Xue

A study has been conducted to remove iron from sulfate solutions using Eichrom's Dipex® extractant, P,P?-di(2-ethylhexyl) methanediphosponic acid (H2DEH[MDP]). It is found that this extractant can effectively and selectively extract ferric ion from highly acidic solutions. Ninety-nine percent of the iron was extracted from a simulated feed solution in a single stage. The separation factor, Fe/Zn, was 10 6 Over 90% of the iron in a loaded organic can be recovered in an aqueous solution by reductive stripping. This paper presents the experimental results. A new process for iron removal using Dipex extractant is described and discussed.

Jan 1, 1999

By Fathi Habashi

IT APPEARS that the phenomenon of ion exchange by which saline water was converted to sweet was known to Moses and Aristotle. However, the credit for the recognition of this process is generally attributed to Thompson (1850) and Way (1850), who reported that when a soil was treated with either ammonium sulfate or ammonium carbonate solution, most of the ammonia was adsorbed and calcium was released. It was later proved by Eichorn (1858) that the adsorption of ions from ground waters by clay constituents was a reversible process. The first attempts to utilize ion exchange phenomena was in the field of water softening around 1906, using natural and synthetic silicates. In 1935 Adams and Holmes in England observed that crushed phonograph records (phenol-formaldehyde and amine-formaldehyde resins) were capable of exchanging ions.

Jan 1, 1970

By John Mastoris, Kostis Dragasakis, Kostas Kouklidis, Shkurtë Gashi, Halil Berisha, Jenuz Bulica

Titan Group’s environmental policy and Sharrcem’s Corporate Social Responsibility (CSR) are the driving forces behind the development and implementation of a comprehensive Rehabilitation Plan at Dimce Quarry, which is the main raw material source for Sharrcem Cement Plant since the 1970’s, located in the municipality of Hani i Elezit in Kosovo. Based on an Environmental Impact Assessment Study and the approved Mining Plan and also on the principles prescribed in the Guidelines on Quarry Rehabilitation, released by the Cement Sustainability Initiative of the World Business Council for Sustainable Development (WBCSD-CSI), Sharrcem has adopted a quarry operation and rehabilitation process in line with the best practices in the mining and cement sector. This paper discusses the background for the development of the rehabilitation plan and the results of rehabilitation activities, as have been implemented over the last few years. The main objective of the progressive rehabilitation plan at Dimce Quarry is to restore the depleted pit and return it back to the original land owners for resettlement. To date approx. 3,4Ha of former mining area has been restored by backfilling and levelling of the depleted closed pit and returned back to owners, who have built their houses and turned it into a living area again. This Quarry has turned out to be a real composition and practical example of preserving and returning back the natural resources in a state compatible with the surrounding environment and with respect to the needs of the local stakeholders. The motivation for business to engage in rehabilitation activities in the first place lies in the belief that the development and implementation of a progressive and practical Quarry rehabilitation plan and restitution of the land will deliver significant environmental and social benefits that outweigh the long-term rehabilitation costs, while maintaining the company’s reputation.

Jan 1, 2017

By E. De Souza, J. F. Archibald

"Many underground mines use cemented backfill to mitigate environmental effects associated with tailings disposal. The large energy needs associated with mine backfilling and cement production operations create significant CO2 and Greenhouse Gas Emissions. This paper introduces post-consumer glass as an alternate, equally effective and lower cost binder agent strategy for cement in backfill that may be implemented to assist in reducing solid waste production, lowering energy costs, and restricting Greenhouse Gas Emissions. Extensive engineering testing, consisting of pipe flow loop tests and strength tests, has been implemented in order to demonstrate the technical feasibility of process integration within industry. An economic analysis has demonstrated that glass is competitive in cost relative to cement and a socioeconomic study has further indicated that the utilization of glass in mine backfill would create a new market for waste glass that requires less processing and reduces costs."

Jan 1, 2005

By Arnaud Colson

1 Good morning ladies and gentlemen. Let me first thank you for welcoming me to this international congress. I?ll have the pleasure to explain to you how the Lafarge group works on its quarry rehabilitation. I will deal with the way quarry rehabilitation has affected all branches of the group trough a global approach. 2 Quarries often are a subject of controversy dividing those are for and those who are against. My purpose is rather to examine where factors of progress lay and how in a quarry such as Lafarge we can include quarry rehabilitation, which is so fundamental dimension of our process. 3 - 4 As these two photos of French quarry show taking into account the environment in the quarry industry has been a recent preoccupation. In less than a century rehabilitation has a dramatically evolved in a positive way. Consequently our group integrate an ecological dimension in its activity. It?s an ethical question as well as a personal view of our role as a responsible industrial group. 5 My presentation is built around 4 points: I?ll begin by explaining why it?s our responsibility to rehabilitate quarries. I?ll go on to fill you in on the method of the project. After that I?ll outline the expected results. Finally I?ll talk about the rest of the project and the way we can ensure this know how.

Jan 1, 2002