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By David M. Spatz

Anyone who scans the modern literature will realize that concepts of leadership have changed during the past few years. And like change in so many areas of our culture, change has been rapid in the perception of leadership. Many traditional leadership traits are still highly regarded and many of the longstanding personal qualities that improve leadership abilities continue to be effective. In the past, though, leaders could rely on dominance, intimidation and fear to accomplish their goals through the actions of others. In contrast, effective leaders today build relationships, provide vision and guidance, and strive for communication, cooperation, trust and employee satisfaction. Earnest leadership involves moral issues like honesty, integrity, fairness, empathy and respect. Modern leaders guide, facilitate and coach, rather than command and direct. But how well equipped are managers in the mining industry to meet the leadership challenges that lie ahead? More importantly, is he or she becoming a better leader? This article outlines steps to becoming a more effective leader. Management consultants stress that the changes that lie ahead will demand swift organizational adjustments and managers who are equipped to lead during times of change (Boyett and Conn, 1991; Hesselbein et al., 1996; White et al., 1996 and Kotter, 1997). Becoming a better leader begins with self-assessment and a commitment to unify all who depend on one's leadership abilities. Simply defined, leadership is leading others. Contrary to common practice, leadership is not about advancing one's own career but about bringing out the best in others. The beauty of modern leadership, however, is that the path of serving others creates synergies. They benefit everyone, including the leader, those the leader manages, upper management and company shareholders.

Jan 1, 1998

By Cloyd D. McDowell

The Federal coal Mine Health and Safety Act of 1969 has been criticized by those who say it goes too far in controlling the activity of private enterprise and by those who say it does not go far enough in eliminating fatalities and accidents in an accident prone industry. Possibly a better evaluation of this legislation lies somewhere in between. From the viewpoint of the coal industry it can be said that through the efforts of those engaged in mining, both the operator and the miner, the year 1969 marked a record year in mine safety with only 190 fatalities and a frequency of 0.84 per million man hours exposure. This outstanding achievement compared to any previous was the result of a determined effort on the part of a concerned industry to improve its reputation as being the most hazardous industry in the nation. After the effective date of the Act, March 31, 1970, the Bureau of Mines assumed complete control of all safety and health activities of the mining industry. Unfortunately, there was no improvement in the safety record of underground mines in 1970 with the total of 255 fatal injuries and a frequency of 1.04 for the year. The number of fatalities declined to 177 in 1971 but the number of underground coal mines had declined from 5,955 to 2,268 during the two year period. Meanwhile, surface mined coal increased from about 38% of total production in 1969 to over 50% in 1971, keeping the annual production of coal at a normal level but involving fewer men.

Jan 1, 1973

Design models for belt conveyors used in mines predict both the belt power requirements and belt tensions. Conveyors with slightly downhill profiles are more complex to predict due to the way that models such as CEMA interpret friction. Performance of a particular conveyor in relation to other conveyors in the same system requires an analysis of natural stopping times, braked times and take-up location. A review of CEMA-based PC models is presented for design of underground multi-flight belt systems.

Jan 1, 1995

By Paul H. Johnson

A new system for leaching many types of ores has recently been developed on a commercial basis by J and J Research and Development, Inc. of Hanover, New Mexico. This revolutionary new leaching system consists principally of three new leaching reactors; viz, (1) a large, air-agitates, column-like reactor for leaching crushed ores that is constructed in an underground environment and has the inherent ability to do a very efficient job of leaching, (2) a vat-like, air-agitated vessel for leaching an rinsing finely ground ores and , (3) an air-agitated copper precipitation column that is built underground and utilizes an inexpensive dense or heavy scrap iron as a copper precipitant. Each of these new reactors have been used in a large leaching plant near Hanover, New Mexico.

Jan 1, 1973

By Andrew J. Neale, Chelvan Veloo

P.T. Freeport Indonesia currently operate a 600,000 t/d mining and 125,000 t/d milling operation in the remote highlands of Irian Jaya, Indonesia. The isolated location and generally difficult working conditions make for challenges not encountered in most North American operations. In spite of this, the mill technical groups have been able to develop and maintain a highly effective level of plant wide automation. This has been achieved through the appropriate selection of available technologies and the implementation of innovative management practices. This paper provides an overview of the control systems currently installed and focuses on those practices which have resulted in the long term success of process control at Freeport.

Jan 1, 1997

By C. R. Kuhn

From 1968 to 1975, most work in surface modification of inorganic materials involved silane coupling agents. A silane coupling agent can be described simply as an oganosilicon chemical having a general formula RSi-X3 wherein the R group is attached to a silicon in a thermally and hydrolytically stable manner, and X is a hydrolyzable group usually having an alkoxy functionality. About 1975, Kenrich Petrochemicals brought into the market place titanate coupling agents. Titanate coupling agents usually consist of one alkoxy group and three functional groups attached to a central titanium atom. Zircoaluminates became available in about 1982. Zircoaluminate organometallic coupling agents, which vary principally in their respective organofunctionalities, arise from a basic technology in which two different types of organic ligands are selectively bound to a low-molecular weight zircoaluminate backbone.

Jan 1, 1995

By Derrick Chambers, George Kevin Chapin, M. Shawn Boltz

Seismic monitoring is one of the few noninvasive technologies with the potential to provide sub-surface geomechanical information to operators of large open-pit mines. Although passive seismic data has been used to refine emerging failure geometries and provide advance indication of surface deformations in the literature, doing so reliably in an operational context is much more difficult. This is due in part to difficulties in estimating and interpreting source locations and parameters in complex, low-stress open-pit environments. Additionally, the high costs associated with implementing, operating, and maintaining deep borehole seismic networks, which are most commonly used to monitor large open pits, can be difficult to justify, especially if monitoring benefits are not readily apparent. In this study, we explore the use of a near-surface nodal seismic deployment, which is commonly used in oil and gas exploration, for monitoring open-pit mining-related seismicity on a short-term basis. A deployment of 18 geophones was conducted on the surface in and around the Bingham Canyon Mine, a large open-pit mine near Salt Lake City, Utah, USA, where we find the small seismic array can detect and locate a variety of mining-related seismic sources, even with an extremely simplified velocity model. We outline the process of creating an idealized velocity model, developing a local magnitude scale, and interpreting the observed seismicity. Of note, we analyze a sequence of mining-induced events associated with a known structure on the south pit wall. We conclude with discussion on how surface-based deployments may be used to augment, or in some cases supplant, borehole seismic networks at large open-pit mines depending on monitoring requirements and objectives.

Apr 26, 2022

By John G. Holmes

The generation of low cost power is but one phase of the TVA program for regional development. During the 36 years since TVA began, growth in its generation of electric power has necessitated a shift from a predominantly hydroelectric power system to a combination steam and hydroelectric system. The addition of steam-electric power plants to TVA's generating system was necessitated by the rapid increase in the traditional and defense demands for electric power in the 80,000-square-mile area served by TVA, the need to firm up the hydroelectric power, and the fact that all available sites for sizeable hydroelectric projects had been developed. At present TVA owns and operates 40 power plants--29 hydroelectric and 11 steam-electric plants. The total generating capacity of the hydroelectric plants is 3,105,430 kw, and the capacity of the steam plants is 13,951,135 kw. This provides a total generating capacity of 17,056,565 kw for the plants operated by TVA. Individual capacity of the 112 hydroelectric units ranges from 10,000 to 67,500 kw, and the individual capacity of the steam-electric units now in operation ranges from 60,000 to 950,000 kw. In addition to this generating capacity, TVA distributes the power from 6 U. S. Army Corps of Engineers hydroelectric plants on the Cumberland River. These plants contribute an additional 725,000 kw. Also, under an agreement with the Aluminum Company of America, TVA directs the stream flows and generation of their 423,715-kw system on Tennessee River tributaries and shares with Alcoa in the increased generation resulting from this coordinated operation.

Jan 1, 1969

By -Ing. Alexander Dohmen, -Ing. Gunter Hagen

In order to improve the thermal environment in deep coal mines, two principles can be applied: firstly, the reduction of heat flow into the air stream, and secondly, cooling of the air current. First of all one should try to minimize the heat-flow rate into the air stream underground by the mining method itself. German coal mines prefer the caving system of advance longwall mining simultaneously on several levels with ascensional ventilation. The effects of descensional ventilation and different face ventilation layouts on the thermal environment are discussed, besides the effects of pneumatic and hydraulic stowing. Application of all mentioned possibilities together instead of today's common mining method would reduce the Basis Effective Temperature considerably. In the future, hydraulic haulage of the raw coal underground substituting belt conveying may be a mean to improve the thermal environment further on. If the working depth of a coal mine exceeds about 1 000 m, cooling of the air stream under-ground will be necessary in addition to the above- mentioned measures. Generally, in German coal mines different types of indirect-contact air coolers located nearby the face are used. Besides such so-called cooling coils, large-capacity spray coolers are used because they work more efficiently if a great cooling duty is demanded. Common designs of both air cooler types and their possible utilizations are demonstrated. Deep coal mines in the Federal Republic of Germany need up to 30 MW of total cooling capacity. Mostly, the needed chilled water is cooled by large-capacity refrigeration plants placed on surface, underground or in combination of the above locations nearby the shaft. Due to the increasing underground cooling demand, the distribution of the chilled water and the control of the air coolers become more important. The conception of a control system is discussed, which is based on the control of the single air coolers. All air coolers of a mine are controlled so as to optimize the supply water-flow rate with regard to the demanded cooling duty of the coolers. On the next upper level of the control system the whole chilled water network and finally the refrigeration plant is regulated. Present research work deals with the use of ice for cooling mines. There are some unsolved problems in this new cooling concept. Some aspects of making, transporting and storing ice are described. The use of ice may probably reduce the cooling costs of German collieries, which are at present approximately 4 DM per ton of saleable coal.

Jan 1, 1989

By James Crosby

The Urad property had been worked intermittently for over 50 years before American Metal Climax (AMAX) started an extensive exploration program on this property in 1961. The detailed studies of the property proved a large ore body of low grade molybdenum ore that could be mined by modified panel caving methods. Mine development and mill construction for a 5000 TPD operation was completed in July 1967. The Urad mine and plant site is located 55 miles west of Denver near Berthoud Pass. The plant elevation is 10,200 feet. The crushing plant is located underground because available surface area is re¬stricted by snow slide hazards. Crushing plant layout and ventilation system design for the Urad mine was based on our operating experience at similar crushing facilities located at the Climax operations. Low speed conveyors of generous width, adequate exhaust volumes at all ore transfer locations, large hoods and good conveyor skirting have made the Urad underground crusher dust control operations very satisfactory. Good maintenance and cleanup of the crusher facilities have made a clean working area with very low dust exposure. The ore from the mine is dropped approximately 1000 feet through ore passes to scraping drifts above the crusher and then transferred to the coarse ore bin by 150 h.p. slusher hoists. A reciprocating plate feeder under the coarse ore bin feeds a 48 x 60 jaw crusher. Ore from under the crusher is conveyed on a 48 in. belt to a vibrating screen where oversize passes through a 7 ft. Standard cone crusher. The crushed ore along with the screen undersize is conveyed on a 42 in. belt to a 1000 ton surge bin.

Jan 1, 1971

By Jiayao Wang, Jian Chen, Leiting Shen, Hongyang Wang, Zeping Cao, Ziru Wang

Large amounts of by-products, including coal gangue, circulating fluidized bed (CFB) slag, and coal fly ash (CFA), are generated during mining, washing and burning of high alumina coal (HAC). The stockpile of these by-products of HAC will cause the pollution of air, water and soil. Meanwhile, the unbalanced regional distribution of bauxite and alumina production has been a critical challenge for the sustainability of world alumina refineries, especially for China. Therefore, economical extraction of alumina from by-products of HAC not only resolves the environmental pollution problems caused by stockpile but also decreases the dependence degree of import bauxite in China. Considering the fact that powder alumina can only be produced by alkali methods, the alkali extraction of alumina from by-products of HAC is summarized in this paper. Based on the formation process of by-products of HAC, the principle, research status, and problem of existing methods were analyzed and discussed, as well as the forecast of research trend. The analyses indicate that simplex recovery of alumina from byproducts of HAC generates large amounts of leaching residue (red mud) with difficulty for disposing, while comprehensive extraction of alumina and silica meets the research trend for clean and high-value utilization.

Aug 25, 2023

By Daniel J. Brunner

The U. S. Department of Energy (D.O.E.) requires that the prospective nuclear waste repository in Basalt at Hanford, Washington, comply with State of California mine and tunnel safety orders. These regulations require that all main fans be installed in such a manner as to permit prompt reversal of airflow. This paper evaluates the requirement of air reversal and the appropriateness of imposing such regulations on the proposed nuclear waste repository in Basalt.

Jan 1, 1988

By Agne Rustan

INTRODUCTION This work is a continuation of the preparatory study by Rustan and Stöckel 1979 (3) and (4) of the possibilities to introduce automatic mine ventilation in Swedish mines and construction works. The preparatory study has been financed by the Swedish Board of Technical Development. In the study it was recommended that an automatic step by step control of the fans near the working place due to diesel exhaust emission would be the best solution. A more advanced alternative would be to regulate the fresh air continuously in proportion to the contamination. The latter alternative has been studied by Boliden Mineral Co in the Udden mine. In this study it was found that the air supply could be regulated continuously but it was very important where the sensors feeling the contamination were placed. An intense study of the environment underground is now being planned by our division together with specialists from the National Board of Health and Safety, The Swedish Work Environment Fund, LKAB and the local Governmental Inspection of the Workers Safety. Different gases, radon, dust, airspeed, moisture temperature and pressure is planned to be measured continuously and correlation between the parameters is going to be established to decide the best measurement parameters for regulating the system. The best situation of sensors is also going to be studied. Despite this work hasn't been done yet this paper covers some of the problems which could be encounted with continuous regulation. In this report the environment has been studied during the test with step by step regulation of fans by radio. Diesel vehicles are the largest polluters under ground in Swedish mines and we have therefore suggested that the large diesel vehicles should regulate the fans. The goal of this study has therefore been to find how active diesel vehicles should be able to start and stop gallery fans at both intake and return air. In this paper different methods for activating fans are discussed. Then the best methods are chosen and tested in the mine. In this study we have found that changes of temperature is a cheap and effective method to start and stop cross cut fans in sublevel caving and radio signals seem to be an attractive system for start and stop of gallery fans. This work has been done in close collaboration between LKAB in Kiruna and the University of Luleå - Division of Electronics and Division of Mining and Rock Excavation. A reference group for the project has been established with ventilation experts from the mines, representatives for the local mine worker's unions and authorities from the local Governmental Inspection of the Workers Safety. VENTILATION SYSTEM STUDIED In the project the ventilation system at LKAB in Kiruna has been studied. The mining method used is sublevel caving with 9-13 m slice height. The air is heated winter time over ground by hot water heat exchanger. The main fans are pushing air down to a main distribution level along the 4000 m long and about 100 m wide orebody. From the distribution level, air is taken through shafts down to the sublevels, where it is pushed through the levels by local gallery fans on both intake and return side, see fig 1. The air ( ~ 8 m3/s) is moving freely through the gallery head. The cross cuts are ventilated with smaller fans, diameter 500 mm, and flexible duct, see fig 2. The aim of this study has been to study how to start and stop gallery- and cross fans and examine the environment when the fans are stopped . In Sweden there are no regulations telling that a minimum of air amount must be supplied. Instead the hygienic limits must be fullfilled.

Jan 1, 1981

By G. J. Joy, J. P. Rider

"Technical advances in longwall mining over the last several years have resulted in much larger and faster shearers that have the capability of mining at speeds over 100 ft./min. This has resulted in a substantial increase in the amount of dust that is generated at the shearer and during shield advances. Meanwhile, increased underground coal production has put a greater demand on longwall dust control systems as some operators have had difficulty maintaining consistent compliance with federal dust standards. To address this need, the National Institute for Occupational Safety and Health [NIOSH] is investigating the effectiveness of a water spray manifold mounted on the tailgate end of the shearer body. The sprays are oriented parallel to the tailgate ranging arm, and these sprays create a water curtain confining the dust plume near the face, preventing the dust from drifting into the walkway. This redirection of dust provides a clean air envelope for the tailgate shearer operator and jacksetters working near the tailgate drum. Three different tailgate spray manifold designs were tested and evaluated at the Office of Mine Safety and Health Research [OMSHR] Pittsburgh Longwall Test Facility. Manifolds were equipped with hollow cone or flat fan water spray nozzles and evaluated at three face air velocities (500, 700, and 900 fpm) and at water pressures of 100, 150, and 200 psi. Reductions in dust concentrations were observed at six face sampling locations for all the tailgate manifold systems at each of the tested spray pressures and face velocities. Based on results from the laboratory tests showing reductions in dust concentrations at sampling locations downwind of the shearer a spray manifold was fabricated and evaluated at an underground operation. INTRODUCTION In 2012, underground coal mining in the United States produced a total of 342 million short tons, with longwall mining accounting for over 53% of this production [EIA 2013]. The longwall mining industry continues to see remarkable and significant improvements in longwall mining equipment and mining practices. Average shift production during compliance dust sampling has increased from 3,500 tons per shift in 1994 to approximately 6,000 tons per shift in 2012. A dramatic decrease in working longwall faces from 80 to 49 has occurred over the same period [Fiscor 2013]. Factors specific to longwall mines that supported productivity improvement include: higher capacity shearers, improved shield hydraulics and control, higher horsepower for equipment, wider face conveyors, and larger faces. Today, the average face width has increased to 1,188 ft., with one longwall operation reporting a face width of 1,650 ft. compared to an average of 750 ft. in 1994 [Fiscor 2009, 2014]. Panel lengths in 2013 averaged 11,307 ft. compared to 7,000 ft. in 1994. Overall production from U.S. longwalls has increased by nearly four percent from 2007 to 2012 with over 182 million tons mined annually [EIA 2013]. Given the volume and rate of coal produced on longwall faces, the potential to generate large quantities of respirable coal mine dust also exists."

Jan 1, 2015

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By L. Zhou, J. P. Rider, T. W. Beck, J. A. Organiscak, Y. Zheng

The U.S. National Institute for Occupational Safety and Health (NIOSH)’s Pittsburgh Mining Research Division (PMRD) recently developed a series of models using computational fluid dynamics (CFD) to study gas distribution around a continuous mining machine with various fan-powered flooded bed scrubber discharge configurations in an exhaust curtain working face. CFD models utilizing species transport model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The study illustrates the gas distribution in the slab (second) cut. The following scenarios are considered in this study: 100 percent of the discharge redirected back toward the face on the off-curtain side; 100 percent of the discharge redirected back toward the face, but divided equally to both sides; and 15 percent of the discharge redirected toward the face on the off-curtain side, with 85 percent directed toward the return curtain. These models are compared against a model with a conventional scrubber discharge where air is directed away from the face into the return. The models were validated against experimental data, proving to accurately predict sulfur hexafluoride (SF6 ) gas levels at four gas monitoring locations. This study includes a predictive simulation examining a 45° scrubber angle compared with the 23° angle for the 100 percent redirected, equally divided case. This paper describes the validation of the CFD models based on experimental data of the gas distribution results.

Jan 1, 2017

By L. Zhou, J. P. Rider, T. W. Beck, J. A. Organiscak, Y. Zheng

The U.S. National Institute for Occupational Safety and Health (NIOSH)’s Pittsburgh Mining Research Division (PMRD) recently developed a series of models using computational fluid dynamics (CFD) to study gas distribution around a continuous mining machine with various fan-powered flooded bed scrubber discharge configurations in an exhaust curtain working face. CFD models utilizing species transport model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The study illustrates the gas distribution in the slab (second) cut. The following scenarios are considered in this study: 100 percent of the discharge redirected back toward the face on the off-curtain side; 100 percent of the discharge redirected back toward the face, but divided equally to both sides; and 15 percent of the discharge redirected toward the face on the off-curtain side, with 85 percent directed toward the return curtain. These models are compared against a model with a conventional scrubber discharge where air is directed away from the face into the return. The models were validated against experimental data, proving to accurately predict sulfur hexafluoride (SF6 ) gas levels at four gas monitoring locations. This study includes a predictive simulation examining a 45° scrubber angle compared with the 23° angle for the 100 percent redirected, equally divided case. This paper describes the validation of the CFD models based on experimental data of the gas distribution results.

Jan 1, 2018

By Karel SPIRKO

The one-dimensional mathematical model of unsteady-state heat conduction through semi-infinite homogeneous and isotropic airway walls with convective heat and moisture transfer between their wet or dry naked surfaces and mine air with time variable temperature and humidity has been developed on the basis of introduction of acceptable simplifications of description of heat and moisture transfer between rock mass and mine air. The analytical solutions for computation of the temperature distribution and surface temperature of the airway walls and floor and for calculation of water vapour pressure near the wet surfaces at given time are obtained by means of the model presented. The presented solutions are derived for general conditions and they could be easily adapted to the actual ones. Results of the model represent basis for balancing heat and moisture transfer between mine air and its surrounding in deep mines under time variable temperature and humidity of the air and enable us to solve complicated dynamic changes of mine air temperature and humidity in an airway system by relatively simple mathematical tools. INTRODUCTION The importance of unfavourable influences and the costs of condition arrangements increases with mine depth. Precision demands on the methods which predict the environmental condition changes and by which it is possible to optimize condition arragements are still increasing. Environmental conditions in deep mines are determined especially by flow velocity, barometric pressure, temperature, and humidity of mine air. Therefore new and more exact mathematical models of mine air flow through airway system and those of heat and moisture transfer between mine air and individual important sources of heat and moisture are developed. The paper presented deals with description and solution of problems of heat and moisture transfer between mine air and airway walls as the rock mass is one of the important heat and moisture sources in deep mines. There are several different approaches to the problem. In some models the moisture transfer between mine air and airway walls is not considered at all. In other models the moisture transfer is described only by certain empirical coefficients. Simultaneous heat and moisture transfer is described seldom. This paper tries to describe in a simple way simultaneous convective heat- and mass-transfer processes taking place on wet naked surface of airway walls by means of corresponding

Jan 1, 1993

By Peter L. Dunn

With the advent of new high-strength magnetic materials, rare-earth magnetic separators have become more common place for processing heavy mineral sands. In many instances, rare-earth magnets have replaced conventional separators such as electromagnetic cross-belt and induced-roll type machines. This paper will present the results from a detailed test program developed to evaluate the performance of rare-earth drum and roll separators for processing heavy mineral sands. The effect of machine design parameters, such as magnetic element configuration and separator diameter, will be reviewed in light of these test results. The impact of basic operating parameters (i.e. feed rate and roll speed) on separation efficiency will also be presented.

Jan 1, 1999