• The brooch coal
• The twofeet coal
• The thick coal
• The heathen coal

Beneath the Heathen coal was the white ironstone, a seam about 4 feet thick containing several layers of ironstone. There was a ready market for ironstone, it was used as a flux in smelting other ironstone or iron ores.

In total 33 mines made up the colliery, each with their own winding plant and means of ventilation. The winding plants were horizontal steam engines of 18hp geared to the drum of about 8 feet in diameter. At the number 27 pit (at Darby End in Netherton) the winding plant was known as "Iron Jack" - a vertical steam cylinder connected to a beam at one end and the other end of the beam connected to the winding drum.

The number 20 pit had the central pumping station with a large steam vertical cylinder having a very heavy flywheel lubricated by a water jet.

Timber Tree Colliery Cradley (from etching by RS Chattock 1872

The actual mining of the coal and ironstone was undertaken by "Charter masters", specially qualified men with training and experience, often being the sons of charter masters. These were contracted with the Earl's mining agents to supply the labour, horses, tools, candles, explosives and light beer to be sent down in small kegs at midday. They were not responsible for the winding plants and the sinking of shafts. They were paid tonnage rates, the rates were obtained by weighing machines on the private railway and by the guaging of canal boats.

The miners were paid on Saturday, the Saturday working day being the same as other days meant that the wives could not do their shopping until late in the day, sometimes as late as midnight. This was later changed to Friday. If the free pit beer was not up to standard the men would complain and frequently refuse to work. To remove this problem it was agreed with the miners' agents to pay an increase on wage rates.

The Government Mining Inspectors recommended that the Charter Masters be relieved of supplying the timber used for support of roadways and working places in order to remove any tendency to economise and thereby increase the likelihood of falls. This was implemented by the Charter Masters purchasing supplies and the accounts were passed to the Earl's agents for payment, charter rates being adjusted to cover the change in conditions. This change had no effect on accident rates.

The last pair of shafts to be sunk was the number 33 pit situated at Quarry Bank. The coal measures were lying at an angle of 45 degrees to the horizontal so that a great thickness was found in the shafts. This was further complicated by the fact that if a roadway had to be driven in the same section of the seam, it was continually altering direction and describing a curved formation on the plan.

A large area of the coal to be worked lay under what was known as the Cradley Pool, which was used for pleasure with rowing boats. The effect of subsidence of the surface is naturally greater with a thick seam than a thin one, so that the pool was drained off into the Mouse Sweet brook (at the eastern edge of the colliery) and into the River Stour to prevent any liability of flooding at the workings. Another large area lay under the surface closely covered by buildings, houses, shops and small factories. The Earl had the legal right to mine coal without being liable to damages. In fact he created a fund for paying compensation to people suffering loss. With their shares of the compensation two owners of factories purchased land elsewhere where they would be free of subsidence and had room for extensions.

Surveying of workings under these conditions presented difficulties and in order to reduce the interference by men and horses at work, when Mr Poole became surveyor of the mine, arrangements were made that the surveying was done after the day shifts work.

The surface winding plant was modern in design, a pair of horizontal steam engines directly coupled to the drums. These engines could accelerate the motion of the cage faster than the pithead pulley would respond, the slipping of the winding rope on the pulley accounted for excessive wear of both rope and pulley. It is said that a race had been run between a stone being dropped with the coomencement of the descent of the cage. Mr Poole never asked to be let down slowly but always took the precaution of filling his lungs to full capacity at the start.

Number 33 pit was the only pit to have a steam-driven ventilating fan. The ventilating current at the other pits was produced by a fire in a recess in the side of the shaft near the bottom of the pit. It was the duty of the cager or onsetter to attend to this fire. Another method was to install a steam pipe from the boilers down the shaft and near the bottom of the pit connected with a circular pipe perforated with holes to direct the steam in upward jets.

A duty of Mr Poole as an apprentice was to pay a monthly visit to each mine to test the flow of air passing through with an anemometer. A register of the results of these visits was kept in the mining office and the manager could order an investigation if there appeared to be less than the average quantity flowing. To get a correct quantity of air, it was necessary to have someone to time a minute's run and the anemometer to be slowly moved from side to side and from roof to floor.