Sutton Colliery is situated about four miles west-south-west of Mansfield in Nottinghamshire. The two shafts, each 15 feet in diameter, were sunk in 1874 to the Top Hard seam by the Skegby Colliery Company and deepened during 1896 to 1897 to the Low Main seam at 467 yards below the surface.

The Top Hard, Deep Hard, Deep Soft, Low Main and Piper seams have all been worked, the Top Hard being exhausted many years ago. At the time of the explosion the daily output was 1,200 tons of which 850 tons were from the Low Main seam, which has been worked for the past 40 years, and the remainder from the Piper seam.

The district concerned-known as 28's-was 1¼ miles inbye, and there the Low Main seam is 580 yards below the surface.

The coal contains 34.1 per cent. volatile matter, 54.2 per cent. fixed carbon, 5.5 per cent. ash, and small percentages of sulphur, phosphorus, and chlorine.

Up to one month before the explosion the seam had been worked by machine cutting at floor level, blasting and hand filling on to belt conveyors, feeding a trunk conveyor. The system was changed when an Anderton shearer coal getting and loading machine was started at No. 28's face on 28th January, 1957.

There were usually employed in 28's district on the day shift 30, on the afternoon shift 12, and on the night shift 10 persons, but on 21st February during the day shift, at the time of the explosion, there were 40 persons in the district including an electrician, a fitter and the under-manager.

The mine was ventilated by an exhausting direct-coupled steam driven Davidson Sirocco double inlet fan situated at the surface and circulating 115,000 cubic feet of air per minute at 33 inches water gauge. A new fan, driven by a Diesel engine and designed to circulate 175,000 cubic feet of air per minute at 7.7 inches water gauge, had been installed and was almost ready and was in fact put into use three days after the explosion.

There is no record of any previous explosion having occurred at this colliery.

Safety lamps. The workings in this colliery are not particularly gassy, but firedamp is found and safety lamps are used throughout. Those in general use are Oldham G.W. electric cap lamps. As firedamp detectors, Protector Type flame safety lamps are supplied to certain workmen. Officials use Protector Type No. 6 flame safety lamps fitted with pyrophor bar internal igniters. Gauzes of all flame safety lamps are of 28 mesh. Automatic firedamp detectors, Ringrose 47/125 Type, are provided, but there appeared to be some reluctance on the part of the workmen to use them, only two being in use in the mine at the time, and neither of them in the district concerned.