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By Terry McNulty

DOUG HALBE: I've decided that we're going to change tactics here and we're going to be nice to people from now on. [Co-chair makes gesture of intense disbelief; laughter] I've also decided who's not going to be a co-chair next year. [laughter] We thought we'd get a couple of experts for our next presentation: some people with a lot of experience. We've asked them to tell us some of the things that all of you operators out there might be able to apply immediately to your plant. Our next two speakers have a tremendous amount of experience, and I think you'll find what they're going to say is highly pertinent to most plants. I looked through their paper and found some things that I could have used in the plants I operated in the past. Our first speaker is Terry McNulty. A lot of you know Terry. He was with Anaconda for a number of years as director of research. He then was president of Hazen Research. I'm going to continue with our new custom of saying nice things. Terry is the guy that I call when I don't know something, and he's always got the answer. SPEAKER: Who do you work for, Doug? [laughter] DOUG HALBE: Remember that we're being nice to people here, Joe. I know that's a stretch. [laughter] TERRY McNULTY: Thank you, Doug. I'm a little bit mystified by this sudden switch of tactics just before I get to the podium. Doug's been a good friend for a lot of years so I guess I do have to be nice. I won't say anything deprecatory about him, but I would have to comment that the observations made by earlier speakers have been far too generous. [laughter] During nine years of consulting as a mineral processor and extractive metallurgist, I have often conducted audits of the performance of client's plants. Usually these audits have been ordered by the plant management in hopes of identifying opportunities for improving processing efficiency or reducing costs. Some of the audits, however, have been financed by the Electric Power Research Institute (EPFU) and member utilities with the objective of

Jan 1, 1998

By Carlton H. Baab

In June, 1981 the Electric Power Research Institute (EPRI) issued a report titled "Control Systems in Coal Preparation Plants" to determine the status of instrumentation and automation systems in the coal preparation industry. EPRI concluded that the control systems presently being employed in the U.S. coal preparation plants "are relatively primitive compared with those in other mineral processing industries; and analytical instrumentation is virtually non-existent". Until recently, clean coal has had a low selling price and satisfying the purchasers' specifications required only minimum cleaning. However, it is becoming more apparent that the increases in coalfired utility power plants forced outage rates are relative to the deterioration in the quality of fired coal. Utility companies are becoming aware of the economic value of reducing the variability of ash, moisture and sulfur in steam coal purchase orders. New contracts are currently being negotiated between electric utilities and coal producers that include provisions for increased penalties if the product does not meet specifications. With tighter specifications on the quality of steam coal, interest is increasing in more sophisticated control systems. One type of device that is currently assisting the preparation plant operator optimize and control the coal cleaning process is nuclear based instrumentation. Nuclear instrumentation includes methods for measuring weight, level, and density as well as for performing elemental analysis on coal. This paper discusses the various types and applications of nuclear instrumentation currently in use in the coal preparation industry.

Jan 1, 1983

By Slavko Ostojic, V. G. Hill

This paper reviews various bauxite classification schemes with respect to the differences in texture, composition and geological associations of the deposits. It demonstrates that a techno-economic classification, based on: a) associated rock type - lateritic versus karstic, b) content of aluminum ore minerals - gibbsite, boehmite and diaspore, and c) gangue minerals (iron oxides etc.) has a geological basis with natural cut-off points for the bauxite types identified. Thus, this scheme is seen as applicable to bauxite resources. It also provides a basis for their rational exploitation taking into consideration the long-term interests of both the bauxite producing and consuming countries. Against this background, the industrial mineral or non-metallurgical grades of bauxite are seen as localised and relatively rare occurrences. Their consumption should, therefore, be aimed toward the specific (hence more remunerative) products as indicated by the bauxite characteristics.

Jan 1, 1984

By John Marshall

Silverton was the queen city of the western mining towns in the early 1900s. Located high in the San Juan Mountains, the town constantly grew and changed. Yet, it was subject to the vagaries and whims of economics, politics and disasters, natural or otherwise. Breweries, smelters and sawmills serviced Silverton's swelling mining population, which reached several thousand at its peak. Two trains a day ran from Durango to Silverton, in addition to trains running from Silverton over the top of Red Mountain on to Ironton. They ran up Cement Creek to the little town of Gladstone and up the Animas River Valley to Howardsville, Eureka and Animas Forks. During these prosperous times, construction flourished. There were plenty of wooden structures, and many of these stand today. The first brick buildings were built by bricklayer Patrick Stanley in 1877. It took quite a while for the first car to arrive. Almost 28 years passed from the coming of the first train to the arrival of the first car. It was brought over 3,840-m (12,600-ft) Stony Pass from Creede, CO, in an incredible journey retold years later by Louis Wyman. "Dad's daydreams were not the idle musings or the fantasies of a mystic," Wyman said. "They had a way of erupting into reality. He advocated and built good roads," he said. "During the summer of 1910, he was up to his sweatband in a project that took in half the state of Colorado. He envisioned an automobile highway, unheard of at that time, running southwest from Denver through the scenic grandeur of the high Colorado Rockies. The road would traverse a thousand miles or more of the state's finest recreational land finally circling back to Denver. Years later, when all of the county roads had been connected, it became known as 'Colorado's Thousand-Mile Circle Route.' Of course, Silverton and the San Juans were bright stars along the way."

Jan 1, 1997

By H. Wu, V. Izaxon

Intensive ventilation is required during the excavation of a mine opening and the subsequent exploitation of the mineral resources. The exchange of heat between the ventilation air and the rock mass has a major influence on the thermal regime of a mine, especially in the initial segment of the airway. In frozen ground, heat flow into the rock mass from the ventilation air can result in the eventual thawing of the permafrost, which can result in roof-rock instability. This paper presents a mathematical analysis of the dispersion process of ventilation-induced heat by thermosyphons placed on the surface of the mine. The principal uses of thermosyphons in the Arctic are to reduce the ground temperature to prevent potentially unstable permafrost from thawing and to increase the bearing strength of the material. The mathematical model of the physical problem, generally known as "the Stephan problem," takes into account the varying thermo-physical properties of air and the frozen and thawed rock mass, the thermal properties of the freeing fluid in the thermosyphons and the phase change of water. Finite-difference techniques were employed to determine the temperature isotherms around the thermosyphons. It was found that two rows of thermosyphons on a 10- x 10-m grid provide an acceptable design spacing for reducing the ground temperature around the mine airway.

Jan 1, 1997

By David A. Zegeer

Since 1980, more than 40 miners have lost their lives by being trapped and suffocating in stock-piles, bins, silos, and similar facilities. Mine Safety and Health Administration (MSHA) is concerned about these accidents, most of which could be prevented if management and miners appreciated the hazard. In February 1986, the coal industry had a suffocation accident that drew national attention. A group of engineers were standing on a coal stockpile. It gave way under their feet. Five of the engineers were buried in the coal and suffocated. As with all fatal accidents, MSHA investigated the cause of this tragedy. I also asked my staff to look into the history of similar accidents. I found out it is rare to have multiple fatalities due to suffocation in material. But, over the years, there has been a long series of individual fatalities from this type of accident. Here are some examples. In Oct. 1985, a coal mine employee in Virginia entered a hopper to collect a coal sample. The feeders were started while he was standing in the hopper. He sank into the coal and suffocated. In Sept. 1985, an employee at a Texas sand company climbed onto a surge pile, to check a problem with sand flow. When other employees found him, the sand had swallowed him. Only his face and one hand were showing. Though the victim's face was clear of the sand, he suffocated before rescuers could free him. Many people do not realize you can suffocate in this kind of situation, though your head is free. Every time you exhale, the material has room to shift and press harder against your chest. Then you have less room to inhale. If this goes on long enough, it gets to the point where you cannot inhale at all. That is what happened to the victim in this accident. In May 1985, a plant operator at a Wisconsin sand and gravel operation purposely slid into the drawhole of a surge pile. He tried to break up large rocks that were clogging the drawpoint. Material piled on the side of the surge pile slid down and buried him. The operator was wearing a safety belt and line. But he was covered by 3 to 3.7 m (10 to 12 ft) of material and could not be pulled free. This incident illustrates another point. A safety line can help. But it is not enough. Workers should never put themselves in a position where loose material can fall on them from above. In Jan. 1985, a young Utah coal miner was waiting for a ride home from a co-worker whose job was at the tipple. A jam developed in the coal bin. The men could not clear the jam from the outside. So the young miner jumped into the bin. He started digging with a shovel at the toe of the coal pile. It caved in on him and he suffocated. The young miner had only three months of mining experience. He had not been trained for work around the coal bin. Since 1980, 16 coal miners and 26 nonmetal miners have lost their lives in loose-material suffocation accidents. Suffocation accidents occur in many areas around mines - bins, hoppers, stockpiles, surge piles, and silos, among others. One recent accident occurred at a surface coal mine in Illinois. The victim was walking over an area that had been drilled and blasted the week before. He fell into a void that had been crusted over with earth. He too suffocated. And many materials have been involved in suffocation accidentscoal, crushed stone, sand, salt, different kinds of ore, ammonium nitrate pellets used in blasting, and a powdery byproduct of iron ore milling called calcine. In addition to fatal accidents, there are near misses. We do not know how many. Most of them are not reported. A person who gets trapped in material, but is rescued, is usually unhurt. MSHA sometimes hears about these accidents by chance, or because they are reported in the local media. We do know that near misses are happening far more often

Jan 1, 1987

By Yasushi Arai

"Among Tokyo Metro’s approximately 200km of subway lines, the Tozai Line that connects Chiba Prefecture and mid-Tokyo experiences congestion of up to 199% at worst and relief of this has become urgent. Therefore, as it is imperative to increase the number of trains operating in the exceptionally congested area from mid-Tokyo going east, a large-scale renovation work is planned between Iidabashi Station and Kudanshita Station that will facilitate turn-back via 3 tracks. While ensuring the safe and stable operation responsible for about 1.35 million passengers daily, this highly difficult work of inner wall demolition and reinforcement of the side walls and floor slabs will only be implemented for 3 hours during late night. This paper discusses large-scale plans to improve turn-back facilities, and the methods of construction therein as an example of operational improvement of a subway network. 1) INTRODUCTION The Tokyo Metro Tozai Line (“Tozai Line”) opened over the entire 30.8 km distance from Nakano to Nishi-funabashi on March 29, 1969. It has the longest operating length of the nine Tokyo Metro lines, and was the first subway line to extend past the borders of the Tokyo Metropolis. Through train services with two other railway companies are available from the Tozai Line. Tozai Line trains join the Sobu Line of the East Japan Railway Company (“JR East”) and the Toyo Rapid Railway Line of Toyo Rapid Railway (“TR”) from Nishi-funabashi Station, and the JR Chuo Line from Nakano Station. The line is structurally distinctive in that 51% of it was built using the open-cut method, 43% of it is elevated and the remaining 6% was built when we used the shield method for the first time 1)2)3)."

Jan 1, 2016

By Lester E. Sutton

The past three years have been the most difficult period in the modem history of the barge line industry. Having withstood the fuel cost run ups of the late 1970s and the imposition of inland waterways system user fees, the industry has struggled more recently with an overcapacity problem of unprecedented proportions. In responding to these challenges, the industry is undergoing important long-term structural changes, with the various individual barge lines pursuing an array of divergent long-term business strategies. This paper discusses these strategies in terms of their probable impact on the industry as a whole, and argues for the survival of a competitive number of large, national, independent barge lines as the outcome most in keeping with the long-term interests of the mining and minerals industry.

Jan 1, 1986

By Charles Bruce

Three years ago, at a reception given during the Steel Institute meeting in New York, I heard the remark, "A new formula must be found for foreign investment." This was immediately following the takeover of U. S. Steel's Matilde operation in Bolivia. Recently, at the World Mining Congress in Lima, Peru, the subject of foreign investment was still a lively topic of conversation. The nationalization of the copper mines in Chile and recent trends in the "Third World" have made all but a few extremely wary of investment anywhere other than in the ?stable? countries. Now, the fallibility of this philosophy has been demonstrated in such "stable" countries as Canada, Australia, and Ireland. Yet, nationalization is not new to us. The events in Chile were classified as disastrous to the affected companies, but so were the effects of nationalization to the majors in Bolivia in 1952. Mexicanization of the mining industry in Mexico was considered impractical by many. Now, those who accepted it are finding it to be workable.

Jan 1, 1975

By D. H. Desy

This research was undertaken to establish the lncendivity of aluminum alloys against rusty steel under frictional impact conditions at typical coal mine fan speeds, to determine any differences in incendivity among various aluminum alloys, and to Investigate less incendive materials as substitutes for aluminum alloys. With a specially designed apparatus, three aluminum casting alloys and three constructional steels were tested for incendivity in frictional impact against rusted steel in flammable methane-air mixtures. Although varying in degree, all aluminum alloys investigated exhibited a high ignition probability under the test conditions; none of the steel specimens tested caused any ignitions under the same conditions.

Jan 1, 1973

By M. D. McInnis

The Jualin Gold Prospect is centered on Johnson Creek, approximately 40 air miles north-west of Juneau, Alaska. The property is on the southern end of the Kakuhan Range with Berners Bay immediately to the south and Lynn Canal to the west. The property is accessible directly by helicopter from Juneau or by float plane to the head of a 5.5 mile gravel road that begins on the north side of Berners Bay and terminates at the old workings of the Jualin Mine near the center of the property.

Jan 1, 1989

By I. Casasbuenas, K. A. Nguyen, E. I. Ngoma, H. Kim, D. Borja, J. H. Park, R. A. Silva, S. Choi

"This study aimed to determine the optimum operating parameters of a continuous bioleaching system to leach arsenic (As) from mine tailings using a mixed mesophilic bacterial culture. The microbial consortium, previously adapted for effective growth at high pulp density and metal concentrations, was mainly composed of Leptospirillum ferriphilum, and Acidithiobacillus caldus. The mine tailings, collected from the Janggun mine (South Korea) contained 11% (w/w) of As. The tests were performed in a laboratory-scale unit composed of three reactors connected in series following a cascade configuration. Agitation speed, air supply, solid concentration, residence time and temperature were systematically optimized by assessing the leaching activity. Several parameters were monitored on a daily basis, including the As released into solution, iron oxidation rates, pH, cell concentration, dissolved oxygen and redox potential. Overall, improvement of oxygen transfer, by optimizing the agitation speed and air supply, presented the most tangible impact on the leaching performance. The highest As leaching efficiency observed in this study was 82%, which supports the feasibility of the process. INTRODUCTION Worldwide, around of 65 billion tons of mine tailings are produced every year (Jones & Boger, 2012). These materials comprise the waste minerals produced after ore beneficiation. Mine tailings usually contain heavy metals (e.g., Cobalt (Co), Lead (Pb), Zinc (Zn) and Arsenic (As) (Falagán, Grail, & Johnson, 2016; Nguyen, Lee, Park, & Lee, 2014). The exposure of these materials to the environment can produce serious health damage and environmental degradation (Martin, Dowling, Pearce, Sillitoe, & Florentine, 2014). Mine tailings management represents a major issue in South Korea. There are more than 1,000 abandoned mines containing stockpiled mine tailings within the territory (Choi, Park, Hong, Park, & Kim, 2013; Kim, Kim, Ahn, Ko, & Lee, 2005; Lee, Lee, & Kim, 1998). These tailings comprise high concentration of arsenic. Therefore, the Korean Government has directed its efforts to developing eco-friendly technologies, for the arsenic detoxification of mine tailings Continuous bioleaching is explored as a remediation technology (Borja et al., 2016). The present study aimed to develop a mixed mesophilic bacterial culture for optimal growth at high metal and solid concentration; and optimize the operating conditions of a continuous bioleaching unit. This investigation forms part of a larger study aimed to develop a bioleaching technique to treat Janggun mine tailings (Borja et al., 2017; Ngoma et al., 2017)."

Jan 1, 2018

By C. D. Hebert, T. Gregor, M. Ghazi, G. J. E. Kramer

This paper describes the recent application of gasketed, precast concrete segmental lining design that has improved tunneling productivity and quality. The speci?c segment arrangement includes: six-piece ring with equal 60 degree gasketed segments, juxtaposed key and counter-key segments, trapezoidal and parallelogram shaped segments, inclined and skewed radial joints and plastic circumferential joint connectors. This allows rapid, but accurate ring erection, reducing mine cycle times. The design avoids cruciform joints, minimizes potential gasket damage and eliminates the need for separate left and right ring molds. The implementation on the Los Angeles ECIS and NEIS sewer projects is described.

Jan 1, 2003

By Wayne Taylor, Martyn Dawborn

Simulation modeling of portions of two platinum mines using General Purpose Simulation Software (GPSS/H™) is presented in this paper. Both mines, located in the Bushveld Igneous Complex PIC) of South Africa, exploit Merensky and UG2 reef horizons, which are processed separately and therefore handled individually from the stope face to surface, requiring duplication of storage arrangements and batch operation of transport facilities. The first simulation assignment concerns the upgrading of a shaft system operating exclusively on Merensky ore, to hoist UG2 ore and increase production. The second assignment comprises a simulation of rock flow from the stope face to surface by way of tramming, inclined conveying and vertical hoisting. Development ends and stope boxholes were modeled down to individual hoppers (cars) demonstrating the versatility of the GPSS/H™ language.

Jan 1, 2002

By T. Dlokweni, A. Z. Toper, A. P. Squelch, R. G. Gürtunca

A collaborative research programme called 'DEEPMINE' was established in 1998 to investigate and research the problems of mining below three and five kilometres depths. Backfill is considered as an important support strategy to alleviate rockburst and rockfall problems in current depths and it will even become a more crucial mining strategy at ultra-deep level mining. In this paper, the evaluation and the application of the current backfill design criteria to the ultra-deep level mining environment are studied and a new backfill design criteria is proposed. The new criteria suggests that backfill should still be placed 60 - 70% of the area mined with a maximum fill to face distance of three metres. Furthermore, the vertical stress generated in backfill should be between 2 - 3 MPa at maximum 25 metres from the face at a corresponding strain value of maximum 10%.

Jan 1, 2001

By M. Deutsch

A common casualty of modern open pit mine optimization is the assurance that the resulting design is actually achievable. Optimized mine plans that consider value and a bare minimum of precedence constraints do not, in general, translate into practical, operational mine designs that can really be used in the field. Ultimate pits may come to a sharp point at the bottom. Schedules may require taking small parcels of material from many disparate areas of the pit in a single period. And grade control polygons may be ragged, narrow, and not minable with realistic equipment. In this paper all of these problems are addressed by encoding these three fundamental open pit mine optimization problems as maximum satisfiability problems. Maximum satisfiability provides a useful framework for problems that are non-linear and may guarantee the optimality that metaheuristics cannot. INTRODUCTION Open pit mines are large and complicated operations, which require significant initial and ongoing investment. A single mine may employ hundreds or thousands of people and creates substantial benefits for both the surrounding and global communities. Planning an operation of this magnitude requires a lot of effort and cannot be done optimally by hand. Mining engineers today rely on many techniques from operations research to guide decision making, and to maximize the value of the mine. Techniques including linear programming, metaheuristics, and network algorithms are all used to solve different problems throughout mine design and optimization. However, techniques based on Boolean satisfiability, including the optimization extension of maximum satisfiability, have not seen much use in mining despite being used in many other fields including electronics design, scheduling, and artificial intelligence. We claim that maximum satisfiability is a useful and meaningful way of expressing and solving optimization problems in mine planning. However, this technique does not come without challenges; the problem is NP-hard, and modern techniques for solving these problems can struggle with the number of variables and clauses that a typical mining problem requires. Also, some of the constraints that mining must contend with do not fit nicely into the satisfiability paradigm. Despite these challenges, we believe that maximum satisfiability provides a useful framework for considering operational constraints and expressing some problems that other techniques can't easily express. Maximum satisfiability can be solved exactly, yielding the true optimal answer which metaheuristics cannot guarantee. In this paper we show the applicability of maximum satisfiability to mining by specifying three fundamental problems in open pit mine optimization. We show how these fundamental problems can be formulated and how they can be extended within the framework of maximum satisfiability. For the remainder of the paper we first give a brief background on common elements between the three problems and an introduction to satisfiability. Then we tackle the three problems; the Ultimate Pit Problem, the Block Scheduling Problem, and the Grade Control Polygon Problem. In the Ultimate Pit Problem we specifically show how to extend the problem to support a minimum mining width – a coveted result for many mining engineers. We then discuss some of the complexities and shortcomings of this framework and possible research directions.

Jan 1, 2019

By Jean-Luc Cornet

Advances in conveyor technology over the past decade have enabled the design and erection of very long overland belt conveyors. Such conveyors usually require head and tail drives to lower the belt tension and belt strength required. This paper provides an overview of the problems encountered in controlling the head and tail drives on such conveyors and some of the solutions developed by CDI for several such projects.

Jan 1, 2002

By Frank C. Di Luzio

REMARKS BY FRANK C. DI LUZIO, ASSISTANT SECRETARY OF THE INTERIOR FOR WATER POLLUTION CONTROL, BEFORE THE ANNUAL MEETING OF THE AMERICAN INSTITUTE OF MINING ENGINEERS, NEW YORK CITY, FEBRUARY 25-29, 1968 POLLUTION PROBLEMS AFTER MUNICIPAL-INDUSTRIAL WASTE CONTROL I am happy to have this opportunity to discuss pollution problems related to the mining industry and the role of mining engineers in protecting our environment. Technological Power and Pollution of the Environment The increasing power of technology to destroy and disrupt the natural environment and the ecological systems upon which life depends has reduced man's margin for error in the use of this power. We must act, therefore, to deter and prevent the occurrence of future ecological disasters such as that caused on the British and French coasts by the sunken oil tanker, the TORREY CANYON, the Clinch River fish kill which occurred when a dam broke and released coal ash from a power plant operation, or that which threatened on the Clark Fork River in Montana when a strike at the Anaconda Copper Company threatened to shut down pollution control activities, thereby endangering fish and plant life on the Clark Fork River with copper waste. In the past, pollution of the environment has tended to be slow. But now, the increased power of technology to damage nature, the loss of in¬sulating space and the compression of time--all reduce our margin for error and the cushion which space and time once provided for our mistakes.

Jan 1, 1968

By Michael L. Ogilvie

The proportion of underground coal production as a percentage of overall Australian production has fallen in the last 10 years, with underground production remaining more or less static at about 53 Mt (58 million st). However, underground coal mining remains a viable industry in Australia, due to use of modern longwall mining systems. In 1993-1994, 26 longwalls were in operation, with total production exceeding 39 Mt/a (43 million stpy). Some of these longwalls achieve productivity levels approaching efficient opencut operations, and in some cases, they exceed them. These high-production longwall mines are not without problems when depth and distances from outcrop increase and the gas content of the seams approaches or exceeds critical limits. When gas content of a coal seam exceeds 6 m3/t (233 cu ft/st), gas flows into the mine may be sufficient to interrupt production from time to time.

Jan 1, 1995

By W. M. Jr. Aubrey, R. L. Stone

INTRODUCTION Most metallic minerals and some industrial minerals have a relatively high specific gravity and most have at one time or another been concentrated by gravity methods. The principles of gravity concentration are straightforward, well documented and easy to understand, but in practice there are many pitfalls that await the engineer in the development of an integrated flowsheet. Gravity concentration equipment has a long history of use and there is a great diversity available. The equipment is capable of treating material over a broad size range, only falling off in efficiency in the very fine sizes. Gravity concentration is also inexpensive, generally free of environmental problems, and commercial equipment can process large tonnages of ore with a minimum of capital cost. As might be expected of an efficient and low cost process, the bulk of the tonnage quickly and inexpensively. Another obvious application is treating mineral deposits such as hematite and manganese ores that are sufficiently liberated after a minimum of crushing to allow production of a coarse concentrate that will meet market specifications. Except for hand picking and mechanical sorting, there is no competing process on coarse size material. Conversely, it is sometimes obvious that gravity concentration does not warrant consideration. Examples are ores that require very fine grinding to attain liberation, for ores where the minerals of interest have a gravity similar to the gangue, and ores that are strongly magnetic. Actually a mineral processing engineer may not know if gravity is the best way to concentrate an ore, but he should have little difficulty recognizing when gravity concentration deserves consideration based upon specific gravity differences and liberation gravity concentration has wide use. size. His challenge then is to At times its selection as the identify and test the applicable primary concentration process is processes, to develop a obvious. Low grade placer deposits metallurgical balance and flowsheet of tin, gold and beach sands usually for the best process, to estimate are only profitable because gravity production rate over the life of concentration is able to throw away the deposit and to make equipment

Jan 1, 1986