Document 44q7oq4Nkr1aORk6oLz4qDeeG

SAFETY IN MINES RESEARCH ADVISORY COMMITTEE ANNUAL REPORT 2001/2002 SIMRAC: Facilitating health and safety research in the South African Mining Industry SIMPROSS (SIMRAC Project Support Services) Private Bag X63, Braamfontein, 2107, Republic of South Africa 2nd Floor, Braamfontein Centre, 23 Jorissen Street, Braamfontein Telephone: +27 11 358 9180/81 Fax: +27 11 403 1821 Web site: http://www.simrac.co.za http://www.simpross.co.za Contents FOREWORD TECHNOLOGY TRANSFER HIGHLIGHTS MINING INDUSTRY HEALTH & SAFETY STATISTICS SIMRAC STRUCTURE SIMRAC AND SUB COMMITTEE MEMBERS SIMPROSS SIMRAC 2002/2003 RESEARCH PROGRAMME 3 4 6 9 10 10 11 SIMRAC 2001/2002 RESEARCH PROGRAMME GOLD AND PLATINUM 13 Experimental and theoretical investigations of mining induced fracturing. GAP 601a 13 Experimental investigation of mining induced fracturing. GAP 601b 13 Fundamental aspects of the integration of seismic monitoring with numerical modelling. GAP 603 14 Use of peak particle velocities at excavation surfaces for optimisation of the rockburst support criteria. GAP 709 14 Underground verification of deflection performance of fibre reinforced shotcrete. GAP 710 14 Methodology and computer program for applying ERR for design of mine layouts on planar reefs. GAP 722 15 Development of a design procedure for energy dissipation strips. GAP 725 15 Development of a vibration absorber for rock-drill vibration attenuation. GAP 726 15 Quantification of dust generating sources in gold and platinum mines. GAP 802 16 Develop discard criteria for non-spin wire ropes. GAP 803 16 Role of illumination in reducing risk to health and safety in South African gold and platinum mines. GAP 804 16 Investigation into conditions under which HFC134a may become flammable. GAP 806 17 Performance of various types of containment support under quasi-static and dynamic loading conditions. GAP 810 17 Criteria for preconditioning at varying stoping widths in different geotechnical areas. GAP 811 17 Effective support system for tabular stopes. GAP 813a 18 Effective roof support for tabular stopes. GAP 813b 18 Review of past research areas - stope and gully support. GAP 816a 19 Review of past research areas - seismology and mine layout design. GAP 816b 19 Realistic dynamic testing of stope face support systems. GAP 818 19 Infrared thermography of loose hangingwalls. GAP 820 20 Assessment of seismic risk in Bushveld complex platinum mines. GAP 821 20 Assessing and evaluating acoustic techniques for 'making safe'. GAP 822 20 Criteria for establishing small span small pillar concept as safe mining method in deep mines. GAP 828 21 Investigation into effects of steel wire rope specimen length on breaking force of steel winding rope. GAP 836 21 Interaction between stope support and ground motion in hangingwall and footwall. GAP 845 21 Investigate rock mechanics aspects of potholes in platinum mines, and their proactive identification. GAP 846 22 Improved understanding of use of short tendons for stope support under rockfall and rockburst conditions. GAP 849 22 Training in strata control for underground workers. GAP 851 22 Experimental validation of mine-wide continuous closure monitoring system as decision-making tool. GAP 852 23 Learning outcomes and effective communication techniques 2 for hazard recognition learning programmes. GAP 857 Application of indirect stress measurement techniques to quantify stress environments in mines. GAP 858 23 23 COAL Best practice inertisation strategy for inbye area of underground fiery collieries. COL 701 Combustion of backfilled areas on coal mines. COL 713 Survey of horizontal stresses in coal mines from available measurements and mapping. COL 802 Dust control for thick-seam wall mines. COL 807 The impact of geotechnical factors on the secondary extraction of coal in the Witbank and Northern Highveld coalfields. COL 810 Rating system for coal mine roofs. COL 812 Process guidelines for the integrated design and planning of underground coal mining processes. COL 814 Develop international links for co-operative research in coal mining. COL 815 Specifications for a portable counting seismometer. COL 816 24 24 24 24 25 25 25 26 26 26 GENERIC 27 Effectiveness of Mass Miniature Radiography for the active case finding of cardiopulmonary tuberculosis patients. GEN 524 27 Ranging open path remote flammable gas detection/ monitoring device. GEN 705 27 Investigate a possible system for "making safe". GEN 801 27 Development of a smart rockbolt. GEN 810 28 OCCUPATIONAL HEALTH 29 Handbook on Occupational Health Practice in the South African Mining Industry. HEALTH 612 29 Evaluation of mass tuberculosis (TB) preventive therapy to improve TB control among gold miners. HEALTH 701 29 Incidence and work-related risk factors in musculoskeletal disorders in the SA mining industry. HEALTH 702 29 Hand Arm Vibration Syndrome in SA gold mines and potential effects of Whole Body Vibration. HEALTH 703 30 Real-time dust monitoring and gravimetric sampling instruments for personal exposure assessment. HEALTH 704 30 Impact of adding sputum screening to existing active case finding methods. HEALTH 705 30 Nervous system effects of environmental manganese exposure of mine workers. HEALTH 711 31 Analysis of emergency care provided for injured miners in SA mines. HEALTH 801 31 Oto-acoustic emission methods for screening early hearing impairment. HEALTH 802 32 Guidelines and material for the technology transfer of X-ray reading skills. HEALTH 803 32 Health hazards in mineral processing plants relating to chronic exposure to multiple chemicals. HEALTH 804 32 Develop percentile charts : semi-quantitative tracking of lung functions. HEALTH 805 33 Best practices in preventing adverse effects of noise and vibration. HEALTH 806 33 Develop technology transfer programme to enhance clinical performance in TB management. HEALTH 808 33 Occupational health services in small and medium other mines. HEALTH 809 33 Assess heat tolerance of female miners. HEALTH 817 33 Determine potential carcinogenic effects on underground coal miners exposed to diesel fumes. HEALTH 824 34 PUBLICATIONS 35 Technology Transfer Highlights SIMRAC co-ordinates a comprehensive health and safety research programme with many of the outputs of the research projects already in application within the mining industry, as practical tools or to guide further work in areas ranging from technology development to reviews of regulations and legislation. A number of these outputs were launched during 2001/2, and these together with others are highlighted below. Handbook of Occupational Health Practice in the South African Mining Industry. HEALTH 612/HEALTH 713 his handbook provides managers, union officials, engineers, health and Tsafety practitioners and occupational medical and hygiene practitioners with practical tools to prevent occupational illness and disability. Information on the identification, assessment and control of hazards and related diseases in the mining industry has been integrated into a single authoritative manual that contains best practice guidelines for use as a practical guide, an audit tool, a planning tool, a reference document, and an educational tool. Coal mining rock engineering book. COL 606 he publication 'Rock Engineering for Underground Coal Mining' was Tlaunched to provide mine managers, underground supervisors and engineers, who have not had in-depth rock engineering training, with a highly practical guide. The handbook covers fundamentals, roof support, pillar design, subsidence - the first real treatment of this issue in a handbook in South Africa, legal issues, multiple seam mines, and high extraction methods. Left: Nielen van der Merwe, Duncan Adams and Bernard Madden with the newly published Rock Engineering book for coal mines in South Africa. Horizontal stresses in coal mines. COL 802 major study into the role of horizontal stress in the coal mine roadway A roof found that that, whilst horizontal stress is undoubtedly present within the coal measures, it is not a significant geotechnical constraint to mining. The one area where horizontal stress was clearly at work was in the guttering and, ultimately, instability within the skin of the immediate roadway roof. A possible method of reducing this potential is "slotting" of the immediate roof. Demonstration of prototype face area support systems. GAP 813 rototypes of two unique systems with the potential to significantly Pimprove safety in terms of reduced rock-related hazards were demonstrated in a mock-up stope. A "walking stope support" has been developed based on a concept which produces a continuous range of 600 to 1200 mm advance. The roof support system consists of two similar support units connected to each other by two cranks. Each unit consists of a 210 x 1200 mm headboard supported by a "wishbone" structure (top and bottom leg) and a self-contained loading/yielding mechanism that keeps the legs apart. Shallow and open cast mining. OTH 501/602 he safety and stability of shallow or open cast mines has been given Tadded impetus with the formulation of a design methodology for pillars in areas of variable surface topography and for the design of stable stope panels that will provide the necessary safe environment for underground personnel working in stopes. In addition, a handbook has been published which emphasises the use of rock mass classifications for the evaluation of stability and support requirements and covers rock mass characterisation, rock mass classification, evaluation of stability in underground and open pit or quarry operations, and determination of support requirements. 4 Technology Transfer Highlights Dust control for thick-seam wall mines. COL 807 rials of a CSIR-recommended Kloppersbos Shearer Spray Curtain system Tshowed significant improvements (> 50 %) in dust levels with engineering concentration levels of below the DME directive of less than 5 mg/m3, except at the tailgate position, being achieved. Use of this system is incorporated in recommendations aimed at overcoming the thick-seam wall mine dust problems. Design of mine layouts on planar reefs. GAP 722 he MINF boundary element code was developed to simulate seismic Tcatalogues that are similar to observed seismicity and to enable mine planners to plan for the future on the basis of expected seismicity. When calibrated for local conditions, this capability has greater potential for planning different mine layouts in situ than using traditional criteria based on numerical modelling alone. The sudden drop in the strength of failed and unfailed rock causes both natural earthquakes and mining-induced seismic events. MINF simulates mining in small steps, and uses estimated strength of intact and previously failed rock, the dynamic strength during the event itself, a growth model whereby slip must grow contiguously and the final long-term strength to simulate seismicity. Safe design of water barrier pillars. COL 702 arrier pillar design charts (hydraulic) have been established to enable Bengineering estimates to be made of the barrier pillar width, tolerable water compartment head or roadway pumping rate required to manage water ingress into workings. An easy-to-use guidebook containing a series of hydraulic design charts has been developed for coal measure strata to aid anyone involved in the management of water on South African underground coal mines. Best Practice: Conveyors. GEN 701 ecommendations on the best design, installation, maintenance and Roperation of conveyor belts cover both material conveyors and man-riding conveyors used underground and on surface. The recommendations are designed to impact on aspects important to a safer working environment. It is evident that an entire culture change is required in the mining industry and that safety of the workers is the shared responsibility of individuals and the employers. Ergonomics of locomotive design. GAP 704 afety aspects of the existing fleet of mine locomotives and rolling stock in SSouth African gold and platinum mines that could be improved through ergonomics interventions have been identified and an ideal design has been formulated. The ergonomics assessment of the existing fleet of mine locomotives highlighted various deficiencies in the design of the working system, most typically at the operator-machine interface. Poorly designed workstations make the operator's tasks more difficult and thus render him more error-prone. Hand Arm Vibration Syndrome (HAVS) in South African gold mines. HEALTH 703 sustainable capacity to diagnose HAVS has been created through research A into determining the prevalence of HAVS in gold miners. The prevalence and severity of HAVS was found to be low and to be associated with operating rock drills. Eight per cent of the subjects investigated had neurological and vascular symptoms, 5 % had neurological and 2 % had vascular symptoms. Doctoral study on ionizing radiation. HEALTH 619 he Cape Technikon conferred its first doctoral degree for a dissertation on Tthe effects of exposure to continuous low doses of ionising radiation on bats, work which was partly sponsored by SIMRAC. The study found the effects of radiation emanating from disused Monazite mines in the Northern Cape on the endangered Cape bat, Rhinolophus capensis, to include signs of dose dependent DNA damage, evidence of abnormal bone structure and a marked decrease in osteoid mineralisation which is an indicator of myelodysplastic syndrome, a progenitor to haematopoietic malignancies. 5 Health and Safety Statistics The long term health and safety performance of consistently, but the short-term trend has shown no significant different mining sectors presented graphically in this section was compiled using the South African Mines Reportable Accident Statistical System (SAMRASS) database. Information on occupational health performance, as captured in improvement. The main contributors to fatalities and injuries are rockfalls, rockbursts and transport systems. Explosions, fires and rockbursts continue to represent the main causes of multiple fatality accidents, the frequency of which has decreased over the last 10 years from eight incidents resulting in 60 fatalities in 1991, to three incidents resulting in 17 fatalities in 2001. the SAMODD database, is currently insufficient to allow for meaningful analyses. rends in occupational health performance can currently not Tbe fully assessed due to the lack of measurement criteria and performance indicators in the mining industry and statutory here are currently 51 different commodities being mined Twhich have been categorised into four mining sectors, namely, gold, platinum, coal and other mines. Analysis of the institutions. However, the influence of HIV/AIDS continues to exacerbate morbidity and mortality. The number of cases of tuberculosis (TB) per 1000 autopsies has increased from 51 in 1990 to 161 in 2000 and the estimated TB fatality rate in the statistics shows that the long-term performance of occupational gold mining industry is 2,5 per 1000 compared to an accident safety in the South African mining industry has improved fatality rate of 1,0 per 1000 workers employed. Accidents and fatalities in different mining sectors during 2001. Figures in brackets represent data for 2000 Sector Gold Coal Platinum Others Total Fatalities Number % of total 192 (173) 17 (31) 50 (46) 39 (35) 64 6 17 13 298 (285) Injuries Number 3 546 (3372) 213 (171) 795 (638) 386 (332) 4 940 (4 729) % of total 72 4 16 8 Total lostdays/worker 29,1 (30,8) 15,9 (16,6) 14,3 (13,1) 14,4 (12,0) raphs and tables giving a detailed breakdown of health and safety trends, according to mining sector, are presented on pages 6, 7 and 8. Fatality and injury ratesin South African coal mines 6 Incidents resulting in multiple fatalities (4 or more) 1984 - 2001 400-f/" 350 300 250 200 150 100 50 0 Fatality rate in the gold mining sector 0 V ny Rockburete Falling into/from Rockfalle Material handling Locomotivee Scraper winchee Inundation Conveyancee Fatality rate in Me coal mining sector za, z?\ z7\ Injury rate in the gold mining seetor 6 5 4 3 2 1 0 Rockburete Falling into/from Rockfalle Material handling Locomotivee Scraper winchee Inundation Conveyancee tojury ratem the coal mining sectoo 1 Z7\ liJI zZ\ Fall of ground Falling into/from Machinery & conveyere Traneport Exploeione gae/duet Electricity Material handling Exploeivee Fatality rate in the platinum mining sector J JL Lm j iMJmL Fall of ground Falling into/from Machinery & conveyere Exploeione gae/duet Traneport Electricity Material handling Exploeivee 0 Fall of ground Falling into/from Machinery & conveyere Traneport Exploeione gae/duet Electricity Material handling Exploeivee Injura rate in the platinum mining secTc 3 zM zZ\ 2 1 iLiduy za 0 Fall of ground Falling into/from Machinery & conveyere Exploeione gae/duet Traneport Electricity Material handling Exploeivee 7 SIMRAC Structure Mine Health and Safety Council Simrac o +> 'o r 3 (0 Simpross Mancom "D C (0 ^=Simpross^= a) <A '> "D (0 r (1) ax a> o ac3 r Strategy and policy (Tripartite membership) Operational Management (Stakeholder involvement) J SIMRAC has adopted a new organisational enhance the effectiveness of tripartite forums that structure and operational procedures with changes being made to the following: require specialised technical skills. SIMRAC has ratified the use of experts, expert panels, facilitators and auditors and will continue to make use of such services to render the new project and programme administration; organisational structure practicable. th e use of external experts, advisers and auditors; The sustained input from industry participants, who and are not only experts, but are also closely involved with the appointment of technology champions and end-user needs, research priorities and implementation incentives for host mines. of research results, will be required. Commitment will also be sought from all stakeholders in the South Project and programme administration African mining industry to ensure that ongoing input is SIMPROSS will be responsible for expediting the maintained from their representatives. approved annual programme, monitoring the financial status, including levy payments, and reporting Incentives for participating mines and champions on relevant administrative matters. Projects will be clustered into new thrust areas to be managed by SIMPROSS Programme Managers. he principle of compensation for participation in TSIMRAC projects will be negotiated with mining groups before formalising any procedures and policies. SIMPROSS progress meetings and presentations Some general guidelines are: have replaced the unwieldy SIMRAC sub-committee The selection of a participating host mine or system. technology champion will only be considered once Programme Managers will monitor progress, and SIMRAC has ratified the development of a detailed assess contractual conformance and recommend research project proposal; payments to contractors. M ine and champion involvement must be The use of external experts, advisers and auditors ermanent committees of the Mine Health and PSafety Council have been advised that the use of professional facilitators should be considered to formalised with a guarantee of compensation at the completion of the research project for expenses incurred during the period of participation; Mining and industry champions may be invited to attend meetings and discussions. 9 Gold and Platinum near the surface of an underground tunnel. In addition, above-mentioned trend seem to be more informative hangingwall block loosening can be promoted by the about the state of the rock and an integration-ready interaction of surface waves with such blocks. model should be capable of emulating such characteristic deviations from the underlying power-laws. A simplified method for the simulation Recommendations for developing and using of blast-induced fracture growth was integrated models for the needs of the mining industry introduced into the DIGS code, and have been made, namely that special care must be showed that the stability of the taken in specifying the initial state of the modelled rock fractured hangingwall can be strongly mass. This implies that a suitable stress-modelling affected by blasting and by the amount module may be added as a part of the integrated of gas penetration into the mining software. induced fractures and pre-existing discontinuities. Simulation results of a GAP 709 The meaningful use of peak particle production blast show (a) that with a velocities at excavation surfaces for the optimisation high pressure blast, the fractures of the rockburst support criteria for tunnels and initially grow radially from the shot stopes hole, until the pressure has dropped and the fracture directions are subsequently controlled by the stress state surrounding the free face. (b) n important criterion in the design of rockburst Aresistant support for stopes and gullies is the peak particle velocity at excavation surfaces that such When the blast pressure is low, the support will be subjected to in a dynamic event. To fracture directions are controlled by the quantify the peak particle velocities in various (b) existing stress state and correspond to geotechnical areas, a Peak Velocity Detector (PVD) was results expected from "smooth" developed and 17 sites, including PVDs and 8-channel blasting techniques. Ground Motion Monitors, were successfully GAP 603 Fundamental aspects of the integration established. A seismic data set comprising all seismic events, of seismic monitoring with numerical modelling recorded by the mine seismic network at TauTona Gold Mine since 1996, was compiled. A procedure for The concept of integrating observational data with filtering the seismic events with respect to their mining-oriented numerical modelling has location was also developed. emerged as the next logical step in the development of Using a fatality database for all accidents in the more reliable computer-based methods for treating the South African gold mining industry, an evaluation of the problems of rock mass stability and damage. dynamic response of the most common support types The most important feature of an integrated applied at the Ventersdorp Contact Reef, Carbon numerical model is the ability to take real data, as Leader and Vaal Reefs was carried out. provided by a seismic monitoring system, and use this The effect of a passing Rayleigh wave on the stability data as an additional input for solving a forward problem of a hangingwall, discretised by fractures and joints, was about the evolution of the physical state of the also investigated. This led to the development of a modelled rock mass. However, not every numerical procedure for determining whether or not keyblocks will model currently in use in the South African mining be displaced relative to the surrounding hangingwall industry is suitable for integration with real seismic data. rock mass as a Rayleigh wave passes. A study was performed aimed at revealing the potential of the software packages currently in use by GAP 710 Underground verification of deflection the South African gold mining industry to be upgraded performance of fibre reinforced shotcrete to integrated models. Special attention was paid to the ability of different models to emulate the basic patterns of mining-induced seismicity. In particular, it was The need for underground verification of the performance of fibre reinforced shotcrete, subject concluded that the ability of a model to reproduce the power-law behaviour of the size distribution of local seismicity is not a decisive factor in selecting the models which are best suited for integration. On the other hand, the deviations from the Condition of panels in the test sites with reinforced shotcrete. 14 AND NUM to high stresses, convergence and dynamic loading, was identified in terms of providing an in situ performance comparison between fibre and mesh reinforced shotcrete; confirmation that the fibre reinforced shotcrete performance matches that of the mesh reinforced shotcrete under large deformations; a comparative performance of various types of fibre reinforced shotcrete; and a comparative performance of fibre reinforced shotcrete of various thicknesses. The performance of various types of shotcrete was monitored in an appropriate experimental field site where the maximum expected magnitude of a seismic event for the region was 3.8. Several large seismic events were recorded near the field test site, but no increase in deformation could be linked with any of these seismic events. The four test sites with the various reinforced shotcretes remained stable in the estimated field stress of 140 to 145 MPa with a stress change of 10,9 MPa. The mesh-reinforced shotcrete exhibited the maximum closure measured of 56 mm as well as a higher crack density in the southern panel. GAP 722 A methodology and computer program for applying improved, inelastic ERR for the design of mine layouts on planar reefs GAP 725 Development of a design procedure for the use of 'dynamic cyclic bending' deceleration systems he deceleration system takes the shape of a Tseries of inline rollers, through which a steel strip is threaded. The end of the strip is then attached to a cable or other device and pulled. This action forces the strip to be drawn through the rollers, bending and unbending to conform to the path set. This bending and unbending motion dissipates kinetic energy in the form of strain energy, which is a resulting resistive force to the motion drawing it between the rollers. These systems can thus be applied in the form of linear brakes or deceleration systems. The research requirement was thus to develop a methodology that could be used to calculate the required dimensions and specifications of such a deceleration system. This study concentrated on the use of these systems in the mining industry in the case of an 'under-wind', which is when the skip overshoots the stopping point and connects the shaft bottom at speed. se of the mine layout design criteria of ERR U(Energy Release Rate), APS (Average Pillar Deceleration Stress) and ESS (Excess Shear Stress) has not provided systems take a good control of seismicity. It has become apparent the shape of a that more complex models of rock mass behaviour are series of inline needed. Furthermore, such models should be rollers, integrated with observed seismicity of recent mining to through which enable better estimates of future expected seismicity a steel strip is within a rock mass of uncertain geological structures, threaded. strength and virgin stress conditions. A computer code that simulates seismicity in three A 1/10th scale model of a shaft was used to dimensions on a shaft-wide scale, and with properties simulate an 'under-wind' condition. Accelerations were similar to those of observed seismicity in space, time measured and a preliminary code was written to predict and source properties, is being developed for mine the deceleration performance via theoretical layout design on the Carbon Leader and Ventersdorp calculations. The data acquired from the scale testing Contact Reefs. The methodologies and the program was compared to the preliminary theoretical MINF write synthetic catalogues of seismic events as predictions and results were favourable. The program actual mine outlines are advanced, and provide the has subsequently been improved and the prediction most realistic mimicking of near-reef seismicity. They has become more accurate, a finding that was also allow for multi-parameter comparisons between supported with the use of a dynamic FEA program to modelled and observed seismicity. further test the capability of the prediction program. The next step to finally test the reliability of the developed theoretical prediction program is to build and test a full-scale model and a site has been investigated. History of two years of mining at 3 km depth and observed (left) and modelled (right) seismicity associated with this mining. Symbol sizes are proportional to Magnitude. GAP 726 Development of a vibration absorber for rock-drill vibration attenuation n a recent survey of the vibration Icharacteristics of mining equipment and impact percussive tools it was concluded that operators of hand-held equipment in South 15 Gold and Platinum T ra n sm issib ility African mines are at risk of vibration-induced disorders. These diseases may lead to vascular and neurological disorders, which may cause crippling injury to the hands and fingers. Several methods exist to reduce the extent of vibration transmitted. It has been demonstrated that vibration absorbers may be very appropriate for such applications and may substantially reduce the transmitted forces. However, the application of vibration absorbers to rock drill applications where operating frequencies change constantly poses serious and conflicting challenges. Small, lightweight and robust designs are required at very competitive cost. For an application where mass is a critical design constraint, innovative designs utilising mechanical or hydraulic amplification may be employed. Such devices introduce geometrical variables that may be utilised to tune the isolation frequencies by effectively changing the absorber mass. Two devices have been built and tested extensively. The first utilised the addition of a second degree of freedom to make it easier to tune the absorber. The second used a heavy tungsten slug to reduce the size of the absorber while still tuning it by changing the pressure in an air spring. Frequency [Hz] Transmissibility curve at 215 kPa. A heavy tungsten slug was used to reduce the size of the absorber shown above while still tuning it by changing the pressure in an air spring. GAP 802 Quantification of dust generating sources in gold and platinum mines ast research on respirable dust has focused on the Pexposures of workers and on issues related to the measurement of workers' exposures. Characterising the dust produced during different activities during mining operations has not enjoyed similar emphasis. This analysis is of importance as a first step in devising effective and efficient measires to control this hazard at source. Data is being gathered which includes a quantification of generation rates as a function of various activities. This will enable the characterisation and ranking of some of the more prominent and common dust sources at points associated with relevant mining activities in South African gold and platinum mines. GAP 803 Develop discard criteria for non-spin wire ropes revious research has led to discard criteria for Pmine hoisting ropes that are part of SABS0293 1996 "Condition assessment of steel wire rope on mine winders". Some of the discard criteria stipulate that a rope must be taken out of service if a given number of wires are broken. However, it has been shown that there is no technology with which internal broken wires can be counted with sufficient accuracy. This has led to the proposal that a correlation be sought between the strength of multi-layer ropes and the signals obtained during a magnetic test. If such correlation exists, then a discard criterion could be that magnetic signal level at which the rope strength is no longer adequate. However, no sample could be obtained from a multi-layer rope that was discarded because of internal broken wires. It has therefore been decided that a conservative discard criterion be proposed if there are very few winders on which the ropes accumulate internal broken wires. A survey has shown that there may be only one or two winders where this is the case. GAP 804 The role of illumination in reducing risk to health and safety in South African gold and platinum mines lthough 'insufficient illumination/visibility' is Ararely cited as the primary cause of an accident, a number of accidents, for example slip/trip/fall incidents and machine collisions, may well have been prevented if sufficient lighting had been provided. Poor design of visual environments can induce errors caused by an inability to see properly as well as confusion, illusions and disorientation and visual discomfort and headaches. The many variables that need to be considered to ensure a safe and healthy visual environment have led to a diverse range of current worldwide illumination and visibility standards. A review of current standards, and research and developments relevant to illumination and visibility in gold and platinum mines was therefore undertaken to update and supplement corresponding information elicited for coal mines in a previous SIMRAC project. 16 Gold and Platinum widespread utilisation of preconditioning as routine practice in faceburst prone mining areas. While many of these implementations were considered to be successful as they confirmed the very positive research results, some of them were reported as unsuccessful. In particular, it was reported that the recommended method of preconditioning is ineffective in high stoping width areas. In order to investigate the potential shortcomings and to test the effectiveness of the technique in these areas, two preconditioning experiments were carried out in a Ventersdorp Contact Reef stope and a Carbon Leader stope. The reasons for failure and the critical success factors for the implementation of preconditioning were identified and, based on the results obtained, the guidelines for the best implementation of preconditioning were updated and a structured implementation process was proposed. GAP 813a The design and development of an effective support system for tabular stopes in gold and platinum mines ince the majority of rock-related fatalities ( 55 %) Soccur in the immediate vicinity of the stope face, there is a need to develop a support system concept that addresses the deficiencies in current stope support systems, and that will significantly reduce fatalities in the stope face area in the short to medium term. Previous research identified the deficiencies of current stope support systems to include poor area cover, poor installation practices, and poor face area support during cleaning. A linked prop and headboard system, named the remotely advanced headboard system, was identified as having the highest potential to significantly improve safety in the face area, while seemingly being a practical system that should not be difficult to implement and maintain. A prototype remotely advanced headboard system was designed and manufactured and initial laboratory tests on the beams indicated that plastic deformation is unlikely to occur up to loads of 20 tons. The system, which is based on a concept that produces a continuous range of 600 to 1200 mm nakes use of a headboard that incorporates a force app<ortioning lever so that the prop force is shared between the beam and a sl pad, therefore limiting the force arried by the relatively weak beam. he beams only carry sufficient load > provide rockfall protection while the aggreagate beam and pad are sufficient to control rockburst energy. In the system, the tempo rary support hinges on the forward headboard of the support system via a link- This concept gives the temporary port more stability and could be installed by one operator. GAP 813b Effective roof support for tabular stopes he objective of this project was to develop and Tsurface test an effective roof support system in the face area of tabular stopes and to do a risk assessment of the system. The roof support system consists of two similar support units connected to each other by two cranks. Each unit consists of a 210 x 1200 mm headboard supported by a "wishbone" structure (top and bottom leg) and a self-contained loading/yielding mechanism that keeps the legs apart. The system yields to both slow and sudden stope closure by a combination of elastic deformation in the wishbone structure and a pressure relief valve. Rapid yielding is mainly accommodated by the flexibility of the "wishbone" structure, and this also gives the system the necessary rebound, since stopes do not only undergo monotonic closure during a seismic event. The system is therefore more likely to stay in place, providing support resistance and energy absorption during the critical moments of the rockburst. To move the system forward, one support unit is collapsed and then hangs from the other by the two cranks. The collapsed unit is then manually cranked forward and re-loaded. Surface tests reveal that three minutes are required to move the system forward by 900 mm. Typically, 20 wishbone support units will be installed in a 30 m panel, and will take two persons one hour to move forward a distance of 900 mm. The support system can be tailored to meet specific mining parameters such as stoping width and average face advance per blast. Testing of the prototype on surface in the laboratory and in a mock-up stope, and a risk analysis identified certain areas that need to be addressed in order to implement the new support system safely underground. matic of prototype remotely iced headboard system. Schematic of roof support system and roof support system in mock-up stope. 18 geotechnical constraint to mining. This conclusion is geological disruptions in the continuity and quality of well supported by the efficiency of the continuous the seam. Work is therefore being carried to identify miner development operations that were inspected. those geotechnical factors impacting on secondary coal Such operations would be constrained to a much extraction in the Witbank and Northern Highveld higher degree if horizontal stress were a primary Coalfields and to quantify these factors with respect to controlling factor of roadway roof stability. resource / reserve classification and to safety. The one area whereby horizontal stress was clearly It was found that those factors that are critical for at work was in the guttering and, ultimately, instability safety reasons are also important with regard to the within the skin of the immediate roadway roof. Whilst financial feasibility of any secondary coal extraction this was not a major production constraint, it does operation. Geotechnical factors affecting safety can represent a potential safety threat, especially in high have major monetary implications, potentially far seam workings where even small pieces of falling beyond that of any actions required to prevent the risk material can inflict serious injuries. A possible method and / or restore the mining environment after a safety- of reducing the potential for guttering and associated related incident has occurred. Therefore, certain skin instability is "slotting" of the immediate roof. factors will prevent the upgrading of a resource to COL 807 Dust control for thick-seam wall mines reserve status, while others may have a similar effect if unexpected coal losses occur during mining. directive of the Department of Minerals and Standing water bodies, spontaneous combustion A (the geology, coal and mining components), the Energy (DME, 1997) requires the dust- competency of the roof, the condition of pillars, the concentration level to be reduced to below 5 mg/m3tiamt e elapsed since the primary extraction, and the the operator's position. However, results from presence of dykes and sills are the most critical preliminary field trials in South African thick-seam wall geotechnical factors in terms of safety, mining method mines indicated that the average Airborne Respirable selection, open cast and underground operations and Dust (ARD) concentration at the sampling stations potential adverse effects on the resource / reserve along the wall face exceeded the DME directive. classification. Similarly, the personal dust concentration levels are above the compliance level of 2 mg/m3. COL 812 Rating system for coal mine roofs any rock engineering Mdepartments in South Africa use locally developed rock mass classification systems to evaluate the condition of the roof, but these are sometimes descriptive in nature and undocumented and in most cases restricted in use to the specific mine. This project attempted to overcome the Intake Feeder Breaker Headgate Shearer Face-Middle Tailgate Return problem by evaluating and documenting all the existing systems Dust concentration levels (8-h period) before and after implementation of that are used in South Africa and others the CSIR-recommended Kloppersbos Shearer Spray Curtain system. that have been developed in other It can be seen that the partially implemented system resulted in significant countries, and proposing the way improvements (> 50 %) in dust levels with engineering concentration forward for the development of a levels below the DME directive, except at the tailgate position. system that could be used universally on South African collieries. In order to overcome the thick-seam wall mine dust The literature review of all existing systems problems, a number of broad areas of change were highlighted that in the mining industry the Q and RMR recommended including maintaining an average face classifications form the basis of many empirical design air velocity of 2,5 m/s; implementing the Kloppersbos methods as well as of failure criteria used in many Shearer Spray Curtain dust-control system; installing numerical modelling programs. Application of these and evaluating the efficiency of the physical shield systems in South African mines has been limited due to curtains hanging from the shield in reducing worker lack of acceptance of the techniques from the industry. exposure; and using a custom-built scrubber system The CMRR promises to overcome most problems fitted on to the shearer. associated with application of rock mass classification COL 810 The impact of geotechnical factors on systems to coal mining. However, certain modifications need to be applied to the system due to different the secondary extraction of coal in the Witbank and conditions to South African coals. Northern Highveld coalfields, specifically related to The investigation into the rating systems being safety used in South Africa highlighted that roof rating any of the problems experienced during the Mextraction of coal are directly related to systems are being used mainly for planning purposes, and not to determine the changing conditions underground. 25 Occupational Health In the Occupational Health area, the priority areas included tuberculosis; the impact of airborne pollutants including respirable dust, diesel fumes and manganese dust; emergency care; hearing impairment; heat tolerance; substance abuse; and environmental ergonomics. An important focus area was technology transfer with a highlight being the publication of an occupational health handbook. HEALTH 612 cupational Health Practice in the South African Mining Industry esearch and other information regarding Roccupational hazards and health effects in the mining industry are of varying quality and are available ^_______ from a variety of sources. This project was therefore NflraV of V ' 0 .pnhgfiflj gl'h Retied initiated to assemble a knowledge base that would In ifis ISmjlh Mining . provide practical tools to prevent occupational illness and disability. A single authoritative manual on the identification, assessment and control of hazards and related diseases in the mining industry and incorporating best practice guidelines has been produced to serve as a practical guide, an audit tool, a planning tool, a referral document to other information sources, a vehicle for technology transfer and an education tool. adapted to provide the framework for a model of TB infection and disease in gold miners, and the impact of interventions including isoniazid preventive therapy (IPT). The model suggested that TB transmission among miners is more intense than occurs in equivalent general populations, or non-silica exposed miners. Because of the high transmission rates, an unusually high proportion of miners are latently infected with TB. HIV infection greatly increases the risk of progression to TB disease following TB infection. In the context of high TB transmission rates and a high percentage of miners latently infected with TB infection, the impact of the HIV epidemic has been profound. The upward TB incidence trends of the last decade can be reversed by a number of different possible interventions, or combinations of interventions. These include treatment of latent TB with IPT. Two main alternative strategies were considered, namely the mass untargeted therapy given during a brief period, and employment-long IPT targeted to individuals known to be at high risk of TB. *HEALTH 702 A prospective study to assess the incidence of and work-related risk factors in the development of musculoskeletal disorders in the South African mining industry iven the narrow and confined working conditions in South African mines, musculoskeletal disorders pose a serious, potential health hazard to South African mine workers. A prospective study to assess the incidence of and work-related risk factors in the development of such musculoskeletal disorders is therefore underway with the ultimate objective of presenting recommendations based on sound ergonomic principles to alleviate them. HEALTH 701 Strategies for reducing the burden of TB infection and disease in South African gold miners: the role of preventive therapy. Phase 1 ompared to many other infectious conditions, the Cdynamics of TB infection and disease are well understood and quantified. Two of the key aspects are first that a latent stage of TB infection, without any manifestations of disease, can exist for many years, and, secondly, that following infection the lifetime risk of TB disease is low in the absence of predisposing factors (estimated at about 10 % for healthy individuals). Pre-existing models were used and estimates of the important constants governing TB transmission were Awkward body postures that can lead to work-related muskuloskeletal disorders. Report not finalised/approved. 29 Occupational Health the presence of sulphur dioxide together with calcium oxide. The plant surveys conducted in this research played an important role in observing these issues, and the methodologies that were developed provided an essential framework for making occupational health risk assessment and management in mineral processing plants more complete, relevant and useful. It has therefore been proposed that the approaches used in this research be used and expanded to cover all chemical hazards associated with routine operations in mineral processing plants. At the same time, the extension of the project will be used to test the previous study on heavy metals, and to reaffirm the conclusions and recommendations in the industries. An interactive CD has been produced with information on 17 mineral processing plants, as well as for 13 generic processes or activities that are applicable to most of the plants. *HEALTH 805 Develop percentile charts : semi- quantitative tracking of lung functions revious research made far-reaching Precommendations pertinent to the practice of spirometric surveillance in South African mines. It was recommended that the optimally valid reference equations it identified be used and be operationally implemented and this project was therefore the first step towards achieving better spirometric practice in the mining industry. The SpiroCharter identity screen. The principal aim was the development of percentile charts for semi-quantitative tracking of lung functions over time. It was intended to optimise medical surveillance by graphing successive spirometric measurements. Optimisation would take place in two ways: maximal use of existing historical lung function data for a particular worker, and early identification of lung function loss by examination of the graphical trajectory over time. Three innovative computer-based products were developed for use in small, medium and large mines. SpiroCharter was developed for small mines for hardcopy use, although generated by computer. The other products are computer-based: SpiroTracker for medium mines was developed in Microsoft Excel, and SpiroAccess for large mines is under development in Microsoft Access. Final product approved and launched. ** In progress. **HEALTH 806 Best practices in preventing adverse effects of noise and vibration ince vibration of the air produces noise, vibration Sand noise are related, both of which are acknowledged as producing adverse health effects in the mining industry. Although knowledge of these physical hazards and their effects has been greatly increased through past research, exposure to noise and vibration has not significantly abated in the industry. There is therefore a need to consolidate what is known, research what needs to be developed and implement best practices to prevent the adverse health effects of noise and vibration in the mining industry. *HEALTH 808 Develop technology transfer programme to enhance clinical performance in TB management revious research reviewed the autopsy findings and Pmedical records of miners who died in 1999, and demonstrated that significant problems exist regarding the diagnosis of pulmonary tuberculosis (TB) in these men. Clinicians failed to diagnose TB in 44 % of cases coming to autopsy, incorrectly ascribed TB as the cause of death in 29 %, and only correctly ascribed TB as the cause of death in 27 % of cases. The omission of accurate, appropriate and timeous clinical history, examination and diagnostic tests was identified as a major contributing factor to delayed, mis- and missed diagnosis. The purpose of this project was to identify, produce and distribute appropriate material to facilitate implementation of best practice with regard to TB in the mining industry. A number of innovative methods and technologies to meet the needs of the end-users were developed and a review of the literature identified process based performance review, undertaken by clinicians' themselves, to be one of the most effective ways of developing successful practice habits. Process based performance review involves the identification of clinically important actions that ought to have been carried out in a particular condition, followed by a periodic review of whether these actions have actually been carried out. The process of performance based process review as developed by this project is sustainable and participation is incentive driven through the mechanism of continuing professional development points, which are a legal requirement for ongoing registration with the Health Professions Council of South Africa. The products (a manual in paper format and a CD version of the performance review process, four posters and a bookmark) were piloted with doctors from the gold, coal and platinum industries and from small and large medical centres. **HEALTH 809 A review of occupational health services in small and medium other mines and the development of the best model for provision of occupational health services in small and medium sized other mines in South Africa ue to their limited turnover, small to medium Dmines in South Africa are in many cases not 33 AL Compiled by Cheryl Langbridge