Christopher J. Bise

Analysis of force variance for a continuous miner drum using the Design of Experiments method

Continuous miners (CMs) are excavating machines designed to extract a variety of minerals by underground mining. The variance in force experienced by the cutting drum is a very important aspect that must be considered during drum design. A uniform variance essentially means that an equal load is applied on the individual cutting bits and this, in turn, enables better cutting action, greater efficiency, and longer bit and machine life. There are certain input parameters used in the drum design whose exact relationships with force variance are not clearly understood. This paper determines (1) the factors that have a significant effect on the force variance of the drum and (2) the values that can be assigned to these factors to minimize the force variance. A computer program, Continuous Miner Drum (CMD), was developed in collaboration with Kennametal, Inc. to facilitate the mechanical design of CM drums. CMD also facilitated data collection for determining significant factors affecting force variance. Six input parameters, including centre pitch, outer pitch, balance angle, shift angle, set angle and relative angle were tested at two levels. Trials were configured using the Design of Experiments (DoE) method where 26 full-factorial experimental design was selected to investigate the effect of these factors on force variance. Results from the analysis show that all parameters except balance angle, as well as their interactions, significantly affect the force variance.

The effects of shiftwork schedule practices and panel dimensions on injury experience in underground longwall coal mines

Over the past two decades, there has been a tremendous growth in the amount of coal produced in the United States by the longwall-mining method. During the early-to-mid 1970s, approximately 120 longwall faces contributed less than 5% of the nationss underground coal output; currently, half as many faces contribute nearly 50% of the nations underground coal output. All this has taken place during a time period when the total underground production grew less than 20%. In addition to the introduction of new technology, new management, operational, and engineering practices have contributed to this explosive growth. Specifically, changing out at the face, lengthened longwall faces, deeper panels, and longer shifts have increased system availability, thereby resulting in these remarkable production gains. However, longer faces and shifts create a concern for the health and safety of face personnel because of increased exposure to workplace hazards and fatigue. This paper examines the impact of increased face lengths, varying mining heights, and increased shift lengths on the accident and injury experience of U.S. longwall mines. Although no statistical significance was established between the three trends and the nonfatal days lost incidence rate, the no days lost incidence rate, and the severity measure — due to limited or nonexistent data, or widely varying incidence rates — a trend was established between the nonfatal days lost incidence rate and shift length. Specifically, for every hour of shift length above eight hours, the nonfatal days lost incident-rate ratio was 1.185, implying that a 18.5% increase in the number of nonfatal days lost incidents is predicted when a shift is extended one hour in the range from eight to nine, or nine to ten hours.

Metabolic analysis of support personnel in low-seam coal-mines

Abstract Support personnel tasks of brattice construction and rock-dust bag carrying were simulated in a laboratory setting. Two different seam heights (1.07 m and 1.37 m) and two different postures (kneeling and stooping) were studied for stooping construction. For bag carrying, a handle was either used or not. All dependent measures, energy expenditure, heart rate and Borgs rating of perceived exertion, indicated that the kneeling posture was preferred over stooping. Similarly, the use of handles reduced the difficulty of bag carrying.

An MIS incident-reporting program for industry

Smal l i n d u s t r i a l e n t e r p r i s e s have a need f o r a c c u r a t e and t i m e l y i n f o r m a t i o n p e r t a i n i n g t o the v a r i o u s unp lanned e v e n t s t h a t occur d u r i n g t he normal course o f o p e r a t i o n w i t h r e s p e c t t o a c c i d e n t s i n v o l v i n g p e r s o n n e l , production ou tages , and property damage. In l a r g e r e n t e r p r i s e s , the r e s p o n s i b i l i t y f o r m o n i t o r i n g t hese i n c i d e n t s i s ass igned t o s p e c i a l groups w i t h i n the o r g a n i z a t i o n , such as the s a f e t y , l o s s c o n t r o l , and q u a l i t y c o n t r o l depa r tmen ts . The sma l l i n d u s t r i a l e n t e r p r i s e n o r m a l l y does no t have the s t a f f o r r esou rces t o commit t o t hese s u p p o r t f u n c t i o n s . As a r e s u l t , t hese t asks a re pe r fo rmed by c l e r i c a l o r l i n e pe rsonne l t h a t have o t h e r p r i m a r y r e s p o n s i b i l i t i e s . The consequence o f t h i s s i t u a t i o n i s t h a t i n c i d e n t r e p o r t i n g i s no t g i v e n a h i gh p r i o r i t y . The r e s u l t i s t h a t management r e l i e s p r i m a r i l y on p r o d u c t i v i t y improvement w i t h i t s a s s o c i a t e d c a p i t a l c o s t as the p r i n c i p l e means o f i m p r o v i n g o p e r a t i o n s . The i n a b i l i t y t o t ap the knowledge o f the o p e r a t i n g pe rsonne l r e s u l t s in l o s t o p p o r t u n i t i e s t o improve t he o p e r a t i o n , and f a i l u r e t o reduce c o s t s a t t r i b u t a b l e t o a c c i d e n t s i n v o l v i n g p e r s o n n e l , and p r o p e r t y damage. The a v a i l a b i l i t y o f m ic rocompu te rs w i t h modera te s t o r a g e c a p a c i t i e s f o r d a t a i s p r o v i d i n g an o p p o r t u n i t y f o r the sma l l e n t e r p r i s e t h a t was u n a v a i l a b l e a decade ago. The m ic rocompu te r has made i t p o s s i b l e t o r e c o r d v a s t amounts o f d a t a in c l o s e p r o x i m i t y t o the o p e r a t i n g s i t e s w i t h o u t c r e a t i n g a d d i t i o n a l paperwork o r c o n t r i b u t i n g t o t he paper shuffle that can distract l ine personnel f rom thei r primary responsibi l i ty of directing operations. Moreover, the microcomputer provides a t o o l t o a n a l y z e t he c o l l e c t e d da ta and t o i ssue r e p o r t s c o n t a i n i n g i n f o r m a t i o n abou t each i n c i d e n t . The purpose o f t h i s paper i s t o demons t ra te how a database-management system can be des igned t o hand le v a r i o u s t ypes o f i n f o r m a t i o n and produce r e p o r t s t o a s s i s t management w i t h d e c i s i o n making in the a reas no ted above. As an example , the needs o f an underground coa l mine w i l l be a n a l y z e d and addressed , but i t shou ld be emphasized t h a t the approach taken i s no t un ique t o t h i s p a r t i c u l a r segment o f i n d u s t r y .

Maximum Demand and Demand Factors in Underground Coal Mining

Maximum demand is an important parameter in electricutility rate structures and in establishing demand factors. If meaningful demand factors for a specific-type electrical system are available, they can be applied in the estimation of demand charges and in the design of new systems. However, the basis for the demand factor is not necessarily the same for both uses. It is the differences in the intended application that are problematic because the measurement and subsequent calculation of utility demand and demand factor is based upon billing practices, not design considerations. Maximum demand, and hence demand factor, which is intended for use in design, should relate in some way to the thermal characteristics of primary electrical components since equipment capacity is determined by allowable temperature-rise limits. A brief review of maximum demand is presented. Then appropriate applications of demand factors are described, as well as recommended methods for their calculation, based upon usage. Included in this is an examination of the thermal characteristics of transformers, motors, and cables, so that a partial relationship may be found between demand and electrical component temperature rise. Finally the conclusion contains a description of the data collection activities and necessary calculations to arrive at meaningful demand factors for an American retreating longwall system.

COMPUTER-BASED INSTRUCTION AS A DIAGNOSTIC TOOL FOR SAFETY TRAINING OF MINE WORKERS

The most recent federal mandate in mine health and safety was the Federal Mine Safety and Health Amendments Act of 1977, Public Law 95–164, which amended Public Law 91–173. The impact of the 1977 Act is not specifically in the areas of regulating and enforcing health and safety standards, but rather in mandatory health and safety training. The current research explores the effectiveness of computer-based instruction as an instructional tool and medium, and evaluates the situations in which it can be integrated into mining industry training programs to enhance their effectiveness. As an example, this study addresses certain aspects of annual refresher training to judge the suitability and acceptability of computer-based instruction as a training-and-diagnostic tool for the safety training of mine workers. The program design and development phases, along with implementation experience at two underground coal mines, will be discussed; cost-effectiveness of such a computer-based training aid will be examined. Overall, the computer-based approach of this study is important and relevant to miner training programs and can be successfully integrated into mine safety training programs to enhance the effectiveness of such endeavors.

Microcomputer-based instruction for miner safety-training programs

Abstract The passage of The Federal Mine Safety and Health Amendments Act of 1977 (Public Law 95-164) is significant because it represents the first instance where the Federal Government, in addition to regulating and enforcing health and safety standards, mandated health and safety training for workers throughout an entire industry. Not only does 30 CFR 48 specify the various classifications of workers that must be trained, it also dictates the topics to be covered and the minimum number of hours that must be devoted to the prescribed training programs. The focus of this paper is on efforts being taken to develop cost-effective, microcomputer-based training aids for the mining industry. Four instructional programs have been developed at Penn State as part of a large research effort in miner training. Examples of the programs will be presented and implementation experience at several underground coal mines will be discussed.

The use of microcomputers in the analysis of innovative longwall mine development systems

Abstract Longwall mining is a full-recovery coal-extraction technique that has gained recognition in the United States for its productivity and safety. However, several key considerations that have limited the further acceptance of the technology include: 1) the high capital costs for the equipment, 2) the dependency of the technique on room-and-pillar mining for panel development, and 3) the total economic performance and reserve configuration of the integrated mining system in the coal marketplace. This paper summarizes a research program dealing with the evaluation of innovative development schemes for longwall mining systems. Two microcomputer programs that were written to facilitate the comparison of different longwall panel layouts are presented.

An Evaluation of High-Voltage Cable-Coupler Performance for Underground Mine Power Systems

High-voltage cable couplers are convenient and widely used accessories in modern coal-mine power distribution systems for aiding in the extension and retraction of power-feeder cables throughout a mine. Coupler design has tried to keep pace with the industrys desire to move to higher distribution levels, but the increase in recorded failures of 15 kV-class couplers, which serve the distribution levels of 12.47 kV and above, have inhibited this transition. The problems associated with high-voltage cable couplers are analyzed. Manufacturing, testing, and mounting practices are reviewed. A discussion of a couplers operating environment is also included. On the basis of the aforementioned conditions, a testing standard is developed and various coupler designs are subjected to its requirements. An analysis of the test results is provided. Although new couplers can satisfy the performance requirements of the cables to which they are mounted, partial discharge appears to be the failure mechanism of concern. The effects of partial discharge are magnified where voids, either in the insulation, cable termination, or potting compound, occur. In this regard, it is shown that the quality of installation of a coupler onto cable is quite critical. By slightly altering the mounting procedure, satisfactory partial-discharge readings are produced on a test coupler.