Pleasley Colliery from the south  1904 - 1919 (FoPP)

1900s

• New headstocks installed at both pits.
• South pit upgraded to full coal winding.
• South screens renewed.
• North winder replaced.
• North pit cages upgraded.

1910s

• New ventilation fans installed.
• Water softener installed.
• Turbine generators installed.
• South pit deepening commenced.

1920s

• South pit deepening and ventilation drift completed.
• South winding and decking arrangements upgraded.
• Steam generation completely upgraded. 
• Deep Hard pit bottom constructed.
• Exploration drivages commenced.
• Deep Hard production commences.
• Large turbine generator installed.
• Main ventilation fan electrified
• New North screens with washer plant constructed
• New South screens constructed
• Deep Hard production terminated.

1930s

• Spoil heap aerial-ropeway started on the north side of the Midland Railway cutting.
• Development of Dunsil  seam commences
• Simon Carves Baum washer plant installed to SW of pit-top.

1940s

• Production underway in Dunsil seam.
• Development of 1st Waterloo  seam commences
• Top Hard production faces more than 2 miles from pit bottom.