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By B. V. Cooper

The word "research" has been used in the title of my presentation somewhat against my better judgement. There are many definitions of the word. But the one I like best comes from Webster's New World Dictionary. It reads: "Careful, systematic, patient study and investigation in some field of knowledge, undertaken to discover or establish facts or principles. ..." I like that. In only 9 words, the definition conveys to me the very essence of what should be going on either in or for the coal industry. Unfortunately, not enough coal-related research is going on. And much of what is being done is, in my view, not really as effective as it might be.

Jan 1, 1983

By R. E. MacDougall

Very few mineral properties spend their entire lifespans from discovery to depletion in the hands of one owner. More likely, properties will have several owners, and partial interests may change quite often. Similarly, mineral companies are bought and sold with frequency, in recent years at what appears to be an accelerating rate. The reasons for selling a property can be manifold -need for additional capital in other parts of the business, need for development capital, realization of a large gain at a perceived high point in the market, pessimistic commodity outlook, retirement of principals, or resolution of estate problems. Regardless of the reasons for a sale, there are specific steps that logically follow. Spruce up the business, package the information, market the property, negotiate the terms, close the sale, and make sure it stays sold. Adherence to certain very basic ground rules in property sales can maximize the profits and minimize the effort.

Jan 1, 1990

By D. Bahrami, G. Danko, W. Asante

"It is prudent to interpret atmospheric monitoring signals in real-time for checking the safe limits of the air conditions in underground mines. In gassy mines, such real-time evaluation increases the safety of operation. In all mines, the continuous monitoring and evaluation contribute to maintaining air conditions to be within healthy and safe limits. Signal interpretation for safety conditions in mines is difficult for many reasons. An increase of hazardous contaminant concentrations can be predicted by signal pattern recognition, root-cause analysis of rapid changes toward deterioration and forward prediction in time using algorithms and numerical models. This paper focuses on analyzing signal patterns to recognize dangerous trends as well as forward predicting the various environmental and working conditions that may affect safety in underground mines. Efficient numerical ventilation model with heat and gas contaminant simulation components is needed for the analysis of real-time atmospheric monitoring data. Computational speed enhancement methods are discussed and tested in numerical examples, using the Jacobian sensitivity matrices for signal propagation prediction. INTRODUCTION The focus area of this paper is mine safety, related to hazardous atmospheric conditions in a mine ventilation system. Improvements by recognizing safety hazards caused by heat of combustible gases or the accumulation of poisonous gases in a mine are addressed. The recognition of safety hazard by manual evaluation is difficult because of the complex nature of information and the large amount of monitored data from measurement by atmospheric sensors such as air velocity, pressure, hazardous gas contaminants and temperature. In order to recognize problem-causing trends, it is necessary to evaluate continuously individual measurement data from the Atmospheric Monitoring System (AMS) of the mine during their time-dependent variations. In addition, the combined effects of various signal trends need to be simultaneously interpreted in their cross-effects. It is very difficult to foresee the possible outcomes of intertwined signatures of various problems by continuous human observation. For example, a steady, continuous methane concentration measurement together with a sharp drop in barometric pressure from the AMS sensors may be a case for worry in future time due to pressure-induced methane increase from the coal seam or the gob (Danko et al., 2013). This future increase can be predicted by a time-dependent Ventilation Air Model (VAM) and its surrogate Air Parameter Predictor Solver (APPS) model. A calibrated VAM or APPS model can indeed predict a likely methane concentration variation in future time as a function of previous and new air pressure as well as air velocity (Danko, et. al., 2013). Such a future trend, however, cannot be seen from the raw measurement data."

Jan 1, 2017

By R. L. Grayson, L. L. Probert

A three-year project focusing on the depth profiling of respirable coal mine dust particles using scanning electron microscopy coupled with energy dispersive X-ray analysis resulted in the development of statistically classified particle-behavior models. The models depict the changing silicon fraction for particles at 5-, 7-, 9-, and 11-keV accelerating voltages, thereby giving a clear indication of the nature of various types of mineral particles. This paper focuses on the results for respirable quartz particles sampled from five underground coal mines across the US. Through statistical analysis of results the relationship between the fraction of surface available quartz in respirable dust samples and coal rank is established for three Pennsylvania coal seams.

Jan 1, 1995

By S. Amirshenava, S. Nadimi

"Premature and unplanned mine closure can result in significant adverse impacts on the environment and community and need to be managed appropriately. Risk management techniques can reduce the negative impacts and risks of early mine closure. Risk Assessment 3D Model, is an efficient tool to quantify risk. The aim of this paper is to identify the mine closure risks in Choghart iron ore mine, and calculate the overall mine closure risk level. The result shows that 51.4% of assessed risks have low risk level and the overall risk level of early mine closure is low. Keywords: mine closure, risk assessment 3D model, Choghart iron ore mine INTRODUCTION The modern mining life-cycle can be divided into three main stages; exploration, mining (opening and production) and post mining (mine closure, and reclamation). Mine closure is the critical component of the modern mining life-cycle and it refers to the period of time when the operational stage of a mine has permanently ceases (Heikkinen et al, 2008). Planned closure occurs due to the depletion of ore reserves, but sometimes it is premature. Laurance (2006) shows that only 25% of mine closure in the past 30 years was due to resource depletion and in 75% of the cases the mines were closed for the other reasons. Ghanbari et al (2010) demonstrated that 48.6 % of copper mine closure in the past 100 years was due to resource depletion and 51.4 % of copper mines have been closed due to other reasons. The main reasons of premature mine closure are as follow (Laurance, 2006; Ghanbari et al, 2010; Maiti, 2013): • Economic, (low commodity prices or high costs) • Geological, (over-estimation of grade and tonnage) • Geotechnical (adverse geotechnical conditions) • Technical (equipment failure) • Regulatory, due to safety or environmental breaches • Social or community pressures • Closure of downstream industry or markets • Flooding or inrush Minaei Mobtaker and Osanloo (2013) developed a mine closure prediction model based on the data collected from closed iron ore mines in the past 100 years. They showed that economic factors, exhaustion of ore reserve and geological conditions are the main reasons of iron ore mine closure. They treated mine closure as a decision making problem in order to predict the causes of mine closure, including the uncertainties of some mine plan parameter such as iron ore price, production and consumption."

Jan 1, 2016

By Richard E. Steffens

The underground portion of Duke Power Company's Bad Creek Pumped Storage Project in northwestern South Carolina consists of a powerhouse cavern (132 m. long, 23 m. wide, 50 m. high), 407 meters of shafts and approximately 3615 meters of tunnel, both lined and unlined, with diameters varying from 4.2 meters to 9.0 meters. A case history is presented, including the early pilot tunnel exploratory work and how this affected design, the design of the project, and the excavation, rock support and tunnel lining work. Problems and experiences encountered during the construction are given. The effects of high horizontal insitu stresses in the granitic gneiss are discussed along with solution taken.

Jan 1, 1989

By Rilung Xu, Jerry C. Tien, Jian Liu

As underground mines become deeper and ventilation networs more complex, ventilation data becomes more complicated and voluminous, making timely ventilation planning and necessary changes more difficult. Oftentimes, ventilation engineers have to rely on special techques using graphs and schematic maps to carry out necessary ventilation planning [1, 4, 5, 6, 9, 10, 11, 12]. A different graphical method, similar to that reported by Taminago and Isobe [10], has been developed in China [13]. This method uses a two-dimensional diagram drawn from available ventilation survey results. It combines both the customary pressure-quantity diagram and ventilation schematic map, and can greatly expedite the interpretation of survey results, facilitate ventilation system design, short and long-range planning, and emergency planning.

Jan 1, 1993

By G. Plenge, M. Diaz

Silver-bearing, bulk sulfide concentrates from several Peruvian mines were autoclaved in a l9-L (5gal) laboratory autoclave in Lima, Peru. Cyanidation of autoclaved concentrates, following a hot lime jarosite destruction step, extracted more than 98% of the silver and more than 95% of the gold. Autoclave operating parameters, such as time, temperature, pulp density and autoclaved solids recycle, were investigated and reaction rates determined. The problems of excessive heat generation, silver solubility during autoclaving and formation of pellets containing unreacted sulfides were addressed. The data presented will be used to design a continuous autoclave pilot plant to provide reliable scale-up data for a 50 to 100 t/d (55 to 110 stpd) facility.

Jan 1, 1994

By D. Carlson

At the Freeport Indonesia Grasberg Mine in Irian Jaya, Indonesia, a system of underground drainholes and surface drain wells have been designed and are currently under construction. The underground drainholes are located at elevations of approximately 9,600 feet and the surface drainwells located at elevations ranging between 12,500 and 13,000 feet. Together they will be used to drain the ground water contained within relatively incompetent rock. This drain system will allow for the successful dry mining of the open pit, and provide slope stability of the pit wall. The surface drain well network, when completed will allow for the draining of ground water to the Amole Drift where the underground drainholes are constructed.

Jan 1, 1998

By Dale J. Sadowski, Richard J. Switalski, Kyle R. Ott

This paper discusses design and construction aspects of shaft construction through rock saturated with petroleum hydrocarbons (crude oil). During the subsurface exploration phase for design of the Hilltop Interceptor project in Cleveland, Ohio natural crude oil was encountered at depths between 6.1 and 61 m below ground surface. The oil-saturated Euclid sandstone contained up to 12,000 mg/kg total petroleum hydrocarbons (TPH), various volatile organics, and had flash points as low as 18.9°C. Interceptor hydraulic design required that construction of access and/or drop shafts penetrate the layer of petroleum hydrocarbon saturated rock. This led to the design of a special lining and some special handling procedures for the excavated material.

Jan 1, 1995

By James R. Fahy, Lawrence A. Hansen, J. David Deatherage

A laboratory testing program was con- ducted to investigate the shear strength along specific soil-liner interfaces for five types of liners of varying thicknesses. Results indicated a bilinear relationship between shear stress and applied normal stresses ranging from 276 to 1000 pKa (40 to 145 psi). Friction angles along the soil- liner interface below the break point normal stress (7.5 to 19 degrees) were lower than those recorded above the break point normal stress (14.5 to 39 degrees ).

Jan 1, 1987

By Kirk L. Prather

Why discuss techniques of accident prod lot on? Would it not be more useful to discuss means to reduce accidents? This discussion will answer these questions by suggesting ways in which effective accident prediction techniques improve the ability to foresee and prevent accidents. Accident Prediction Process The secret to accident prediction is to utilize the tendency for history to repeat itself. The same circumstances and the same human behavior that produced accidents in the past tend to produce accidents in the present and the future. The ability to predict accident occurence in the future by projecting from the past is a statistical process. In a bookmaker's jargon this means "playing the odds" or "the percentages". A horse or a sports team may be beaten on any given day, but by skillfully assessing the factors of past performance and assigning odds, many clever bettors make money in the long run.

Jan 1, 1973

By I. S. Parrish

This article offers one of the infrequent looks at Chinese mining. It includes a brief review by Parrish of a tungsten symposium held there and his comments on and impressions of the mines he visited. In early Oct. 1981, a Symposium on the Geology of Tungsten was held in the Peoples Republic of China. There were approximately 100 participants. Half of them were Chinese. The remainder included representatives of the United Nations, geologists from other nations in Southeast Asia, and 10 invited specialists from other countries. The invited guests included K.F.G. Hosking of the Camborne School of Mines, United Kingdom; C.S. Hutchinson of the University of Malaysia; K. Mattson of LKAB Int. AB, Sweden; T. Kwak of Latrobe University, Australia; K. Sato and S. Ishihara of the Geological Survey of Japan; M. Clarke of the Department of Mineral Resources, Indonesia; P. Bateman of the US Geological Survey; and the author. R. Horsnail of Amax was also invited but was unable to attend because of delayed visa clearance. The meeting was noteworthy because the Chinese were presenting more than half the papers. In addition, following the formal session, everyone was taken to the famed Jiangxi tungsten district and toured four mines there. Organization and Background The idea for a symposium on tungsten geology was brought up in late 1979 during a visit to China by the Economic and Social Commission for Asia and the Pacific (ESCAP) and, in particular, by members of the Regional Mineral Resources Development Centre (RMRDC) of the United Nations. Discussions continued and in the spring of 1981 invitations were sent to selected geologists throughout the world. China's Ministry of Geology handled arrangements, scheduling, and logistics. Travel to China and all correspondence before the symposium were coordinated by the Bandung, Indonesia Bureau of RMRDC. All costs in China were met by the Peoples Republic of China. Airfares and "per diem" enroute for participants were paid by respective governments, sponsors, or individuals. On Oct. 10, visiting participants entered China from Hong Kong. The author and a few others traveled by train to Guangzhou (Canton). Most of the group flew in the next day. The entire group was then taken to Nanchang, traveling by sleeper train and arriving on Oct. 11. The symposium group stayed at the Kiangsi Hotel, where the meetings were held. Meetings Oct. 11 was a day of orientation and rest. The group was taken to an art museum and treated to a Chinese opera movie. The formal meetings began on Monday, Oct. 12. Simultaneous translations aided presentations, though more than half the Chinese speakers delivered their talks in English. The acoustics and sound system were excellent, and the Chinese provided 35-mm and overhead projectors. There was no screen, however, and the yellow, painted wall that was used detracted from projection clarity. In general, the Chinese papers were detailed, thoughtful, and professional. Some, naturally, were stronger than others. Taking them as a unit, one derives the following sequence to the Chinese approach to tungsten exploration: (1) Geologic investigations with mapping at a scale of 1:200,000 accompanied by only minor geochemical or geophysical work. (2) Geophysical investigation with regional gravity and magnetic surveys directed toward identifying deep, tectonic systems and seeking granites in thick, crustal environments. (3) Geochemical sampling in-

Jan 6, 1982

By A. S. Azman

In collaboration with Kennametal Inc. and corry rubber corporation, the U.S. National Institute for Occupational Safety and Health (NIOSH) developed a drill bit isolator to address noise overexposures associated with roof bolting machines in underground coal mines. NIOSH laboratory studies confirmed that the drill bit isolator reduces noise during drilling. Field studies were needed to confirm that a noise reduction could be obtained under working conditions and that the device was sufficiently durable. This paper reports results of field tests of the device conducted at five underground coal mines. Noise reduction was assessed by comparing the operator?s noise exposure during drilling with and without the drill bit isolator. Durability was assessed by recording the number of holes and total feet drilled with each bit isolator until either the test period ended or the device failed. The results from these tests showed that the device is an effective noise control in a mine environment. The field-tested drill bit isolators provided a noise reduction of 3-5 db(A). Of nine devices tested for durability, five exceeded 610 m (2,000 ft) drilled and two exceeded 762 m (2,500 ft) drilled before failure. Durability issues found in the field tests led to final production optimizations that have resulted in a commercially available product for drilling with 35-mm- (1.3-in.-) diameter roof bits and hexagonal drill steels.

Jan 1, 2012

By G. W. Heunisch

The properties of Neutra-Fix® and Neutra-Ment®, two new lime substitutes for treating acid mine drainage (AMD), have been compared with lime and Allcament®, two products presently in use for AMD treatment. The two new products are basically dolomitic byproducts and produce sludges that are more compact than those from lime. Sludge settling rates are faster than lime with iron concentrations after 24 hours that comply with Environmental Protection Agency (EPA) regulations. Material utilization and optimum pH are reported.

Jan 1, 1988

By F. Calizaya

A booster fan is an underground ventilation device installed in the main airstream to handle the total quantity of air circulated to one or more working districts. It is installed in a permanent stopping and equipped with airlock doors, a monitoring system and interlocking devices between the main fan and the booster fan. When adequately installed, a booster fan can be used to reduce the main fan pressure, reduce leakage and decrease the power consumption. However, an inadequate installation can increase the likelihood of mine fies and recirculation of air contaminants. This study identifies hazards associated with the operation and maintenance of booster fans. It analyzes the accompanying risks and recommends control measures to reduce those risks to acceptable levels. The ventilation network of an existing coal mine was updated to include a booster fan. The hazards associated with the operation of this fan were identified, the risks analyzed and the esponse to each failure mode established.

Mar 1, 2014

By Rainer Alles, Markus Keller

INTRODUCTION For overland conveyors of several kilometres length and as well as wide for conveyors designed for high mass flows, the cost for the conveyor belting share is 40% to 50% of the invested cost 173. The German Standard DIN 22101 is used for calculation and dimensioning of - conveyor belts and belt conveyor components. Developments in rubber technology and conveyor belt design required a revision of the standard released in 1982 121, which was published in August 2001 131. New research results and publications 16-9, 13-15] led to a better understanding of the material behaviour and their influences on conveyor belts. Test and calculation methods have been established to determine the most important parameters which are related to the performance of a conveyor belt line. These parameters are • The running resistance of the idlers • The indentation resistance of the belt • The dynamic splice efficiency • The distribution of belt load in the splices, transition zones and on pulleys. As a result, new rubber compounds with low indentation losses allow the use of reduced friction coefficients and thus lead to reduced power consumption, smaller drives and lower belt tensions. The deeper understanding of the flux of forces within belt splices led to both optimised splice design and optimised rubber compounds which significantly improve the dynamic splice efficiency. Therefore, in accordance with the standard, the benefits of these technologies and the better understanding of material behaviour allow a reduction of belt strength still maintaining sufficient safety factors. Thus engineers are enabled to calculate belt tensions more exactly and users are encouraged to pay more attention to starting and braking techniques. DETERMINATION OF DRIVE FORCE According to the DIN standards the resistance to motion generally has to be determined for each different section of the belt conveyor including upper and lower run separately. The necessary drive power P is calculated as [ ] with v as the conveying speed. The total of all resistances to motion of carry and return run can be determined as [ ] FHo and FHu are the primary resistances consisting of the running resistances of the idlers, the indentation resistance of the belt, the fulling of the conveyed material and the flexure of the belt. While indentation resistance and idler resistance are measurable, they have been deter- mined to be responsible for up to 70% of the primary resistances covered by FH. Further FN is the secondary resistance that covers, for example, the resistance of feeding points and scrapers. Fa are the total slope resistances and Fs is the total of all special resistances, resulting, for example, from belt steering devices. These three resistances should be neglected in the following discussion. For conveyors where a determination of the substantial parts of the resistances to motion is not possible, according to the new DIN standard [31 a determination of the drive power is acceptable by using the fictitious friction factor) [ ] In this formula the index i identifies the individual section of the conveyor, 1 is the length of the section and MR, MG and ML are the related masses of the idlers, the belt and the load in kg/m. The fictitious friction factor f determines the ratio between the overall resistance to motion and the total of moved masses within the

Jan 1, 2004

It had been more than a decade since this many booths were occupied at an SME Annual Meeting, but at the 2010 meeting in Phoenix, AZ 630 booths were sold to 470 vendors from the entire spectrum of the mining and minerals industry. Exhibitors such as Metso, FLSmidth, West-Tech, ABB, NIOSH, Eriez and Resource West took their usual prominent places on the exhibit floor and were joined by newcomers such as tunnel boring machine manufacturer Herrenknecht AG, Frontier Kemper, the International Society of Explosive Engineers and more than 100 other first-time exhibitors. On the floor, one could find everything from a new pair of boots to a new career in the recruitment pavilion where some of the biggest companies in mining (Barrick Gold, Freeport-McMoRan, Newmont Mining, etc..) set up shop. The following is a look at some of the companies and products that were on display at the 2010 meeting. For information about displaying at the 2011 annual meeting in Denver, CO, Feb. 27 to March 2, contact exhibits@smenet.org.

May 1, 2010

By C. S. Simons

The aphorism that provided the title of this paper is probably a couple of hundred years old, but it still expresses a fundamental truth in the metals industry. This truth will be illustrated through a brief review of the major developments in the extractive metallurgy of the oxidized ores of nickel - the "laterite" ores. While the details to be discussed are for the most part specific to nickel, a close parallel with other commodities - particularly in recent years - will be apparent even to those whose interest in nickel itself is slight. Thus it is hoped that this paper will be stimulating, at the least, to anyone who is concerned with the implementation of process improvement, "Invention" in the present context means any change from "conventional" process technology that shows a reasonable chance of reducing costs, increasing revenues, or both, in the production of a commodity. This can be anything from a simple rearrangement of flowsheet steps to a completely different basis for processing. And the result may reduce costs by more efficient use of energy or labor or reagents; may increase revenues by better recovery of the primary product or by introducing the recovery of previously ignored by-products; may insure sales volume (and thereby cash flow) through higher product purity or an improved product form. "Necessity" is the perceived need to attain at least one of these classes of results. This perception of necessity, however, varies widely from management to management and from project to project.

Jan 1, 1983

By Peter C. Busse, Henry M. Giegerich, Ronald K. Netolitzky

Zimbabwe The Republic of Zimbabwe is situated in south central Africa and north of the Tropic of Capricorn. The country is land-locked, bounded on the north by Zambia, on the south by the Republic of South Africa, on the east by Mozambique and on the southwest by Botswana. Nearly 400,000 sq km in area, Zimbabwe is bigger than both France and Spain and nearly three times the size of England. The outstanding physical feature is the central plateau, known as the highveld, which is about 650 km long and 80 km wide at an elevation of +1,200 m, and on which the Jena Mines is located. Because of its elevation and inland position, Zimbabwe's climate is temperate, generally drier and cooler than is normally expected in the tropics. Zimbabwe's population is in excess of 10 million. English is the official language, with Ndebele and Shona being the main ethnic languages. About one million people live in Greater Harare, the capital city. The basic unit of currency is the Zimbabwe dollar, which has depreciated substantially over the past few years. Currently (November, 1995), the exchange rate is $US 1.00 = $Zim 9.00, compared with $US 1 .OO = $Zim 2.50 in 1991. Project Area The Jena Mines Complex is situated in central Zimbabwe (Figure 1), in the Silobela area of the lower Gweru River valley. The mine site is 270 km from Harare by paved and gravel road. The Jena Mines property consists of a single rectangular (8 km by 5 km) shaped mining lease with an area of approximately 40 sq km (Figure 2). Annual average precipitation is 720 mm falling in the summer months between October and April. Mean daily maximum temperature is 24°C in October and mean minimum is 14°C in July. The southern parts of Zimbabwe have experienced drought conditions over the past four years which has affected water and power supplies. The countryside in the Jena area is generally low relief with a gentle slope to the northwest. The mine site topography is flat with an average elevation of 1,210 m. Zimbabwe Mining Industry Zimbabwe has a long mining tradition, particularly for gold. In the 1,200 years preceding European colonization, it is estimated that about 4,000 ancient mines produced between 600 and 800 tonnes of gold. Since the turn of the century more than 1,700 tonnes of gold have been produced. An excellent infrastructure has developed to support the mining industry. This includes a well- maintained system of paved roads, railway links to major mining areas, an electricity grid covering most of the country, and numerous industries manufacturing a wide range of mining supplies. Jena History The claims in the Jena Mines area are among the earliest registered in Zimbabwe. The gold potential was easily recognized because of extensive ancient (pre-European) workings. European trading beads from the 14th Century have been recovered from anthills in the mine area. Development of the Jena Mines commenced in 1898 and several mines have operated intermittently over the past 90 years. The recorded cumulative historical production from the significant producers of Jena is tabulated in the following:

Jan 1, 1996