Environmental conditions at Linby Colliery, 1981/82

Respirable dust concentrations at Linby Colliery are tabulated for the period April 1981 to July 1982, when the Pneumoconi’osis Field Research sampling programme was terminated. Information regarding seam worked, outputs, method of working, dust control and manpower, together with the associated respirable dust concentrations, is presented in a series of face charts.The mean coalface respirable dust concentration at Linby Colliery was 3.2 mg/m3 for 1981/82 and 3.6 mg/m3 for the period April to July 1982.The total dust concentrations are given and were on average six times higher than the respirable dust concentrations. The shift mean concentrations of nitrous fume observed,are also listed.The composition of the dust will be reported later, as an addendum to this technical memorandum. The annual output is approximately three per cent higher than for the previous year, 1980/81.2.1.3 Method of working Five power-loaded faces were worked during the survey period, with up to four being in production at any one time. The same method of work (see Tables 2a – 6b) was adopted on all the faces except that, on A20’s face, the tailgate was not fully mechanised.One face heading (A20’s) was driven during this period with a Thin Seam Miner. All other headings, Which were in mixed strata, were bored,fired and power loaded.2.2 Ventilation and dust control2.2.1 Ventilation All faces were ventilated antitropally. The average air quantities, temperatures and relative humidities are shown in Tables 2a – 6b.Exhaust ventilation systems were adopted in 50 per cent of the headings. The average quantity of air ventilating each of the various headings was 3.67 m3/s. All these ventilation data were obtained from the Colliery records.2.2.2 Dust control The dust control equipment for faces is shown on the face summary charts (Tables 2a – 6b). On A2’s face, sprays fixed to the roof supports were directed onto the conveyor. Where,as in A8’s and All’s, an advanced heading was driven at the intake end of the face, the air from the heading was passed through a dry dust filter before it was allowed to re-join the main air current,thus reducing the dust level at the intake end of the face.In headings, all cutting and loading machines were provided with sprays. Martindale Type *Uf respirators were freely available to all workmen; some 58 men were regular users, and however, on average, 68 respirators were serviced per day.2.3 Manpower and occupational groups The colliery population at the end of the period under review was 1105, of whom 329 (30 per cent) were classified as faceworkers, 564 (51 per cent) as non-faceworkers and 212 (19 per cent) as surface workers. The number of occupational groups in use at the end of the period was 37t split as follows:-Pace groups 21Elsewhere underground 13Surface 33. SAMPLING PROGRAMMEThe sampling and evaluation were carried out as before (SINHA & ANNIS, 1981). Sampling underground was done by some 37 volunteer instrument carriers (SINHA & THOMAS, 1972), with a target of 17 samples per volunteer in the 17 months period. The collection of 48 per cent of the samples was supervised by the unit’s investigators, who also took the surface samples.