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By Elwyn H. King, Thomas R. Kuesel

I. CONCEPT MARTA's Peachtree Center Station is being mined out of hard rock, directly beneath Atlanta's central business district, with minimal surface disruption during construction. Its cost is competitive with that of a conventional cut-and-cover alternative owing to its design concept, which utilizes the rock as a primary structural and architectural material. II. PLANNING The station was originally planned for cut-and-cover construction. However, Peachtree Street is unusually narrow for a main business street (generally 78 feet (24 m) between building lines) and cut-and-cover construction would therefore be very disruptive to surface traffic and severely restrict access to adjacent buildings, including Peachtree Center, Atlanta's showcase business/commercial complex. (See Fig. 1.) Tunneling had been considered, but was initially thought [ ]

Jan 1, 1979

By F. T. Paleari

Radial gas holdup profiles have been measured in a 50x400 cm flotation column using a multi-cell conductivity probe. Three different bubble generation systems were examined: up to eight vertical filter cloth spargers, three horizontal filter cloth spargers, and three (horizontal) Cominco-type spargers. The variables tested were: number of spargers, symmetry of their arrangement, and height above spargers. Batch water with up to 20ppm frother concentration was used. The general observation is that the profiles tend to be uniform (i.e. flat) with some exhibiting a slight wavy shape. The vertical sparger arrangement proved the most difficult to achieve profile symmetry. The horizontal spargers gave uniform profiles at right angle to their length but a decreasing gas holdup along their length; the Cominco-type spargers gave slightly less scatter in the data. Switching off selected spargers (to simulate malfunction) did not produce strong asymmetry in the profiles.

Jan 1, 1993

By T. E. Durney

In the Fall of 1987 The Wellmore Coal division of The United Company installed a fines separation circuit in its #20 plant near Big Rock, Va. The addition of the fines circuit included a bank of classifying cyclones and two flotation units; one a conventional 4 cell, 34 m3 Wemco cell, the other an 2.4 meter diameter by 7.6 meter tall, 28.3 m3 column flotation cell. The new fine coal separation circuit is depicted in Figure 1. The column flotation cell is manufactured by the Deister Concentrator Company, Inc., under the trade name Flotaire. The Deister Flotaire column cell utilizes a counter current flow arrangement and a different means of generating air bubbles than that of conventional mechanical flotation cells found in coal processing plants. Other features include diffusers for additional air supply and a froth washer. This cell is one of the few commercial scale column cells processing coal.

Jan 1, 1990

By J. S. Hall

The productivity and fuel efficiency of iron-ore blast furnace operations has greatly increased in recent times. These improvements, particularly to the Japanese steel industry, have primarily arisen from process engineering studies of the blast furnace and associated operations such as sintering. The development of fluxed sinter based on iron-ore fines reacted to produce highly reducible, low slag sinters has contributed further to a reduction in fuel requirements. The Pilbara province of Western Australia is a significant source of these iron-ore fines supplied to the international market. Increasingly, this market is being offered high quality ores from other foreign sources. To technically assist companies in improving the processing efficiency of ores, and to improve the technical marketing of ores by modelling the processing characteristics of Australian/international ore blends, the Commonwealth Scientific and Industrial Research Organization (CSIRO) is actively assisting the industry by researching the general theme of 'iron ore from mine to metal in this paper we outline progress towards a numerical description of: a. ore deposit classification. b. Degradation during transport. c. Direct reduction of iron ore. d. Liquid bath ore reduction/smelting. e. Industrial sintering.

Jan 1, 1986

By Paul Dean Proctor

The world's population by 2000 A. D. may approximate 6.5 billion and the United States' 304 million. South Asian population increases between 1970 and 2000 A. D. will be triple the projected population of North America. Such anticipated dramatic and probably traumatic increases in world population yield grave concern for the standard of living in the world and the United States. The people of the United States currently consume 32 percent of the world's energy and similarly large percentages of the world's mineral raw materials. With only 6 percent of the present world's population and slightly smaller percentage by 2000 A. D., much expanded world-wide production of energy and raw materials will be required to maintain even a standstill living standard. A minimal 2 percent increase per year in the standard of living in the United States and a 4 percent increase elsewhere in the world, beyond the demands of the estimated population increases, suggest the magnitude of the increased need for energy-mineral raw materials and the possible crises the world will face in these areas by 2000 A. D. Mineral engineers and scientists with broad educational backgrounds will be required in greatly increased numbers to help alleviate, and possibly avert, expected energy-mineral raw materials shortages of the next millenium. Explorationists, mineral engineers, commodity economists, environmentalists, city, county, state, and federal mineral materials planners and coordinators, and metallurgists will be among those most needed. AIME membership in the second century of the Institute's history will contribute directly to this personnel pool.

Jan 1, 1971

By T. A. Doyle

Column and batch test methods are used to simulate and model the leaching of various mining by-products. Batch tests are simpler, while column tests more intuitively represent the field conditions to be simulated. Projects that have included different types of leaching tests illustrate the strengths, limitations, and associated uncertainties of each. Column and batch tests have been used to evaluate arsenic solubility in leachate from treated copper smelter flue dust, to simulate the leaching of pit wall rock from a proposed gold mine, and to simulate the release of uranium from aquifer materials.

Jan 1, 1998

By M. C. Fuerstenau

Collophane, cryptocrystalline fluorapatite, is examined as a substrate for plant water and wastewater remediation. The attenuation of Fe3+, Cr3+, Fe2+, Cd2+, Hg2+ and Pb2+ is presented as a function of metal ion concentration, amount of collophane, initial pH and conditioning time. TCLP results for Pb2+ contaminated collophane are presented. Mechanisms of adsorption for divalent and trivalent species are suggested. Key words: Collophane, Wastewater remediation, Heavy metal removal

Jan 1, 2003

By J. D. Miller, C. L. Lin

"The use of 3D X-ray tomography analysis for plant-site characterization of coarse particles at a sampling rate of about 3 kg/min for particles ranging in size from 150 mm to 1 mm at a voxel resolution of about 150 µm is now possible. This is quite a significant advance in X-ray tomography technology and promises to be useful for plant-site coarse particle characterization—size, shape, composition, density, texture, grain exposure and mineral liberation—with a response time of minutes after receiving the sample. This paper discusses applications in the mineral industries, including the coal industry, aggregates industry, metal mining and the processing of industrial minerals.IntroductionPlant-site characterization of coarse particles at coal preparation plants, crushed stone/aggregate plants and mineral processing plants is needed to improve plant capacity, product quality and/or process efficiency. Not much online coarse particle characterization is being done at these plants. Only some limited information regarding particle size is obtained online from reflected light images using analyzers such as the OPSA, Split and WipFrag™ analyzers. Even the laboratory analysis of coarse particles has been difficult because of the large amount of sample required to ensure statistical significance of the results. During the past several decades, laboratory 3D characterization of particles from energy and mineral resources by X-ray tomography has been demonstrated and used to good advantage (Miller and Lin, 2004, 2009).Three-dimensional X-ray tomographic analysis has its origins in the medical services industry, where it is used to provide internal images of the human body. It has since been developed for nonmedical applications as well (Banholzer et al., 1987). Figure 1 shows a schematic diagram of the cone-beam geometry micro-CT system. In our case, X-rays from a microfocus X-ray generator are partially attenuated by the sample (a packed bed of particles) that is made to rotate in equal steps in a full circle about a single axis of the particle sample. At each rotational position, the surviving X-ray photons are detected by a planar two-dimensional array (image intensifier) large enough to contain the shadow of the specimen. These two-dimensional projection images are collected using conventional video technology. The video signal for each projection is then converted to a two-dimensional digital array by an image processing system. Finally, a threedimensional image is reconstructed from the collected set of projection images."

Jan 1, 2016

By D. R. McMullin

The purpose of this paper is to provide a method for mine planners and engineers to evaluate on a conceptual basis if a shaft or a ramp is most suited for their particular underground access requirements. Mine planners and engineers are often raced with the decision of choosing which method of underground access is best suited for their particular requirement. Underground access can be provided by a shaft, ramp, adit, or slope for either exploration and/or actual production operations. This paper will focus on the construction cost and schedule differences between sinking a shaft and excavating a ramp which are currently the most typical access alternatives used in the western United States. It would be wrong to state that one method is superior to the other in every case. There are many variables to be addressed, and the degree of sensitivity of each of them will eventually dictate which method is the most suited to the particular circumstances. This paper compares the construction cost and schedule or sinking a shaft to excavating a ramp at different depths given different ground and hydrological conditions. This comparison provides mine planners with "rules or thumb" that may be applied to the access selection process.

Jan 1, 1994

By Georges Cote, Ehsan Alavi, Eren Kusdogan

The City of Toronto's Coxwell Bypass Tunnel is currently being constructed by North Tunnel Constructors (NTC) ULC, a joint venture of Jay Dee Canada, C&M McNally Tunnel Constructors and Michels Canada. This project includes construction of approximately 10.5 km of 6.3 meter finished diameter rock tunnel, five 20 meter diameter storage shafts and eleven tunnel connection drop shafts, along with associated deaeration and adit tunnels. 120 m of Starter tunnel and 70 m of Tail tunnel were excavated with roadheaders to help with the launch of the TBM and as part of the contract base scope work. JayDee Canada in Collaboration with Everest Equipment Co. developed an innovative approach to design and build a stand-alone Ring Machine Erector nicknamed Enterprise to erect precast segmental lining in Starter and Tail tunnels in lieu of Cast-In- Place concrete. This paper describes the design and provides feedback on the innovative procedure used to install the rings.

Jun 23, 2024

By Agus Sasmito, SRIVATSAN JAYARAMAN SRIDHARAN, Akash Adhikari, Purushotham Tukkaraja

The amount of toxic fumes produced during blasting operation depends on the types of explosives used, product formulation, degree of confinement, conditions of use, and reactivity of the explosives with the host rock. Ammonium nitrate and fuel oil (ANFO) is still the explosive of choice due to its lower price and ease of use/loading. If not properly monitored and controlled, toxic fumes produced from blasting operations can have serious health hazards [1]. This paper presents a novel technique developed to track trapped fumes during a development blasting.

Aug 1, 2022

By D. S. Dinsmoor

Boron, estimated to comprise about 0.001 percent of the earth's crust (Fleischer 10), as an element is never found free in nature, although its compounds are found in many localities. the borates are the most important. Sassolite (B(OH)3) and boracite (Mg6C12B1406), non-borates, are-of-minor importance. The crystal structures of most natural borates are still unknown. A classification based solely on the ratio of boron to the total number of cations has been devised (Palache 28). This classification divides the borates into four, sub-groups; anhydrous borates, hydrated borates, borates containing hydroxyl or halogen and compound borates. Only four or five minerals of the hydrated borates group have ever been used commercially. In more recent years, the sodium borates have comprised all but a 'small fraction of all borates used. Borax, the hydrated borate compound, is the most important of all boron compounds. It has been used so long and so often that the layman often confuses borax and boron and, applies the terms synonymously.

Jan 1, 1958

By H. Sevim

Belt network simulators developed in the last two decades are reviewed. Critical parameters in belt network design are identified, and the capabilities of belt simulators in providing values of these parameters are investigated. An alternative design model that optimizes values of the critical parameters is introduced. To illustrate the capabilities of the alternative model, a real life case is treated and the outcomes are discussed.

Jan 1, 1990

By E. Ben-Awuah, H. Askari-Nasab, N. Al Habib

Open pit mines are getting deeper with time and transportation expenses are increasing because of the increasing haulage distance. In-pit crushing and conveying (IPCC) is getting popular in deeper open pit mines as a suitable alternative to truck haulage because it offers a lower operating cost due to shorter haulage distance and less truck requirement. Semi-mobile in-pit crusher, currently the most popular IPCC system, is relocated every two to five years and the short-term plan needs to be updated accordingly. Short-term planning with IPCC is an area of research that has not been explored extensively yet and hardly any model can generate short-term extraction sequence considering an IPCC in place. This research work proposes a mixed integer programming model to generate short-term production plan within a time horizon of 12 months. The objective of the model is to optimally allocate shovels to minimize cost of material handling and maximize revenue subject to meeting plant requirement, maximum allowable tonnage variation and IPCC location constraints to achieve production and NPV targets set by strategic plan. The proposed model has been implemented in a hypothetical case study for verification. The comparison of results between scenarios with and without IPCC is expected to justify the use of IPCC in large open pit mines from a short to medium term perspective. A semi-mobile IPCC system with one relocation is considered in the case study.

Feb 1, 2023

By M. Galetakis

The difficulties that rise during the evaluation of multiple-layer lignite deposits come from the deposit structure (alternating lignite layers with intercalated material of varying thickness), as well as from the limitations of the applied selective mining. Thin layers of lignite and interbedded waste layers are grouped under specified assumptions regarding thickness and ash content, to form the exploitable blocks. However, in practice the decision for excavating a block is made under subjective constraints of different importance or by using uncertain data. Advances in Fuzzy Inference Systems (FIS) have provided a new approach to the evaluation of multiple-layer lignite deposits. FIS have the ability to handle imprecise or incomplete or linguistically ambiguous information and to incorporate them into decision-making processes. In the developed FIS (Mamdani type) new linguistic variables, concerning with working conditions, operators? experience and production were involved. The FIS was used for the estimation of quality characteristics and reserves of the exploitable lignite produced from Southern Field mine, Ptolemais (Greece).

Jan 1, 2005

By C. Roos

"Nearly every input to a mine plan is based on an estimate. The estimates may be from sample data, historical information, models, or personal opinion, but in all cases, these values are simply expected values (means). In real life, we do not get to iterate the exact conditions at our mining operation many times to ensure that that average value is attained. The expected value also tells us nothing about the spread of values that that input might take on. The result is a significant amount of unquantified uncertainty in our mine plans. Unfortunately, it is often too expensive or time consuming to update planning processes and software. This paper presents a proof of concept spreadsheet scheduling tool that can be utilized to incorporate many geologic realizations (simulated models) into the mine scheduling process. While this POC is not intended to be a detailed model of uncertainty, it is to show that there are stepping stones available for mine planners to begin to embrace uncertainty and produce more achievable plans without requiring a significant change in their planning process. INTRODUCTION Mining companies have included quantifying uncertainty, or at least risk, as a requirement of project justification for many years, however many times this process lags behind the traditional mine planning process and the results are rarely used to improve the plan. Nearly every parameter used in a mine plan is an estimate and the mine planning engineer should recognize and even embrace the inherent uncertainty in those parameters and its effect on their forecast results. While many of the uncertainties are beyond the scope of the traditional mine plan (e.g. global market uncertainty, socio-political uncertainty, environmental uncertainty), some uncertainties can, and should, be included in the mine planning process. Many mining engineers have incorporated techniques such as Monte Carlo Simulation or Discrete Element Simulation to understand the range of productivity that can be expected for an operation but most still rely upon one estimated model for what is likely the critical component of technical uncertainty, the geologic resource. Modern geostatistical methods can provide multiple ore body realizations to provide a thorough unbiased “picture” of the geologic uncertainty but most traditional mine planning techniques are not formulated to allow for multiple (100-200) realizations of each material quality/grade parameter. Commercial software companies and research groups are progressing with development of tools that can incorporate geologic uncertainty, and even optimize extraction plans in the uncertain environment. Unfortunately, this author believes that a significant number of mining operations will not be able to adopt these techniques due to the computational requirements of the advanced techniques and the costs associated with implementing proprietary software. In an attempt to encourage mining engineers to embrace the inherent uncertainty in their mine plans, this paper presents a cost-effective alternative that can be developed in-house, at any mine, to schedule mid to long-term mine plans while continuously monitoring the uncertainty in the results. The author hopes that by demonstrating the usefulness of such a system that mining companies will encourage engineers, geologists, and geostatisticians to find ways to incorporate this powerful data into their processes and procedures."

Jan 1, 2017

By M. R. Moon

The mine fire at Wilberg Mine in 1984 reached the surface resulting in the failure of the vertical ledge forming the roof and entrance for three main intake portals. The fallen material was covered with a concrete cap to seal the air from the mine. As the mine was recovered and ventilation pressure was placed on seals on the perimeter of the fire area, the concrete capped rubble proved ineffective. Due to the steep and rugged terrain and the inaccessibility to the portals from underground, horizontal holes were drilled into the portal entries and three seals were placed remotely. The seals in conjunction with pressure balancing the seals around the perimeter of the fire area resulted -in the control of the mine fire.

Jan 1, 1993

By W. Robert Power

Stone is considered by many to be the premium material for beauty and durability in all kinds of construction. Its use dates to the dawn of civilization and only buildings made of stone have survived from ancient times. The use of stone relative to other materials declined from the beginning of the present century reaching a low point in the third quarter, but there has been a resurgence in the use of stone in construction during the past decade, due probably, to new techniques for producing stone, a greater recognition of its beauty and durability, and greater affluence among consumers. The aesthetic appeal of stone is attested to by the many attempts to simulate it in synthetic materials. Today, natural stone is considered by many to be the ultimate in aesthetic appeal, durability, and ease of maintenance. Consumption of dimension stone has increased dramatically during the past decade. The US Bureau of Mines reported that the total value of US consumption in 1978 was $1 13 million and that total imports were valued at $65 million in 1979 (Anon., 1980). In 1989 consumption of domestic dimension stone was valued at $208.3 million and imports at $525 million. This dramatic increase occurred after demand had decreased at an average rate of 2.5% in the two decades prior to 1978 (Anon., 1980). More than half of the imports come from Italy, but production of dimension stone has increased worldwide spectacularly. Meaningful statistics on dimension stone are hard to acquire. The finished piece of stone is a highly value-added product, but stone may be sold as rough blocks, sawed slabs, or finished product. The same piece of stone may therefore be sold and reported three or more times. Furthermore, although the quantity of stone is most commonly reported in tons, stone cladding is more often sold by the surface area and at the same price for different thicknesses. By any measure, however, the production and consumption of dimension stone has increased dramatically during the past decade. A significant indication of the resurgence of stone was the introduction of two new trade publications during the 1980s. Stone World (Tradelink Publishing Co., Inc., Oradell, NJ), introduced in 1984 is published monthly and Dimensional Stone (Dimensional Stone Institute, Inc., Woodland Hills, CA), introduced in 1985 is published monthly. Both magazines provide useful information on new technology, market trends, producing areas and companies, and other information not previously available.

Jan 1, 1994

By Paul J. A. Lever, Robert H. King

Human operators, geological conditions, equipment changes, mining sequences, and roof conditions are some of the continually changing operating conditions that drive a dynamic mining environment. These dynamic characteristics make it difficult to automatically analyze mining data because attributes change as the mining environment changes. Mine monitoring systems could provide mine managers with much more useful information than they do presently, if automatic analysis were possible. Automatic analysis of sensor data is also key to autonomous mining systems. This paper describes artificial intelligence (AI) and sensor fusion based sensor data analysis techniques developed over the past four years. These techniques were used to classify machine operating events by continuously monitoring machine power usage in a continuous miner section at an under- ground coal mine. The result is a report similar to an industrial engineering time study. First, numerical pattern classification techniques broadly identify operating events. However, domain knowledge about inter-machine and intra-machine interactions is necessary to identify and refine dynamic event boundaries. By implementing AI and sensor fusion based techniques we are able to classify machine events more accurately and recognize more specific events. These techniques could easily be applied to many different mining sensor data applications

Jan 1, 1993

By A. Torrance, M. G. Seo

Velocity of detonation (VOD) is an important variable when evaluating the performance of mine blasts. Typically, for a VOD measurement, individual probes have to be loaded into each blast hole that requires a measurement, which increases the loading time and is not representative of the whole blast. Experimental studies of electromagnetic pulse (EMP) from the detonation of explosive charges show that electric and magnetic field signals are observed when chemical explosions occur in the air, at the ground surface, and in the underground. EMP has the potential to evaluate VOD of the whole blast without impeding the loading process. Due to a variety of physical causes which make the electromagnetic effects complex, measuring EMP of the detonation of explosive charges has not been fully studied yet. Five different antennae were tested with explosives, which are commonly used in mining industry. Among the five antennae, aluminum and copper tape, and wire were successful to detect the EMP. INTRODUCTION The measurement of the velocity of detonation (VOD) helps in evaluating and comparing relative performance of explosives in mine blasts. A VOD of an explosive is usually predicted by empirical mathematical equations or measured in-hole by VOD meters. However, conventional methods to measure a VOD have constraints: only a limited number of holes can be measured because cost of consumables for such systems is very high, and systems only allow a certain number of holes to be measured. The measurement cables have to be placed into the holes prior to loading with explosives which means that preparing to take the measurement is time consuming and has to be well coordinated with the mine. In order to evaluate VOD for a whole blast, there is a possibility of using electromagnetic pulse (EMP) from the detonation of the explosives. As there are many parameters that affect the generated EMP from explosive charges, measuring EMP of the detonation of explosive charges has not been fully studied yet. Most studies conducted relate to military related explosives, not the ones frequently used in mining industry. This research has been performed to have a better understanding of EMP from the types of explosives which are commonly used in the mining industry. To discover a way to detect EMP efficiently, five different types of antennae have been studied in the air and in the underground blasting conditions: coil, monopole rod, log periodic, wire, and aluminum and copper tape. LITERATURE REVIEW Conventional methods of measuring VOD Over the years, demands for more accurate theoretical predictions and physical measurements of the effects of the explosives have increased. Especially when both demand and commodity price decline, mining companies are keen to understand the effectiveness of explosives since it has a direct relationship with fragmentation, which influences their production rate. Since the 1940s, various methods have been devised to determine VOD of explosives.

Jan 1, 2019