The Midlothian Coalfield is a coalfield

Coalfield

A coalfield is an area of certain uniform characteristics where coal is mined. The criteria for determining the approximate boundary of a coalfield are geographical and cultural, in addition to geological...

 in southwest Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 situated immediately to the east and southeast of Edinburgh

Edinburgh

Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...

. It is geologically continuous with the East Fife Coalfield

Fife Coalfield

The Fife Coalfield was one of the principal coalfields in Scotland. Over fifty collieries were in operation at various times between the middle of the nineteenth century and the closure of the last pit in 1988...

 beneath the Firth of Forth

Firth of Forth

The Firth of Forth is the estuary or firth of Scotland's River Forth, where it flows into the North Sea, between Fife to the north, and West Lothian, the City of Edinburgh and East Lothian to the south...

 though the undersea coal

Coal

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 reserves have only been partly exploited. There were undersea workings extending from Prestonlinks Colliery. The sulphur content of the majority of Midlothian coals is less than 1% making it especially suitable for modern requirements.

The following seams were worked. They are shown in rough stratigraphical order thought not all seams are present throughout the coalfield. Those shown in bold were worked to the greatest extent:

Within the Scottish Coal Measures Group (Middle and Lower Coal Measures):

• Clayknowes Coal
• (Musselburgh) Splint Coal
• (Musselburgh) Rough Coal
• Beefie Coal
• Musselburgh Jewel Coal
• Golden Coal
• Little Splint Coal
• Cowpits Five Foot Coal
• Glass Coal
• Salters Coal
• Musselburgh Nine Foot Coal
• Musselburgh Fifteen Foot Coal
• Pinkie Six Foot Coal
• Musselburgh Seven Foot Coal
• Eskmouth Extra Coal

Within the Upper Limestone Formation:

• South Parrot Coal

Within the Limestone Coal Formation:

• Great Seam Coal
• Gillespie Coal
• Blackchapel Coal
• Kittlepurse Coal
• Peacock Coal
• South Bryans Splint Coal
• Stony Coal
• Ball Coal
• Loanhead No 1 Coal
• Corbie Coals
• Andrews Coal
• South Coal
• North Coal
• Stairhead Coal

Within the Lower Limestone Formation

• North Greens Coal

Within the West Lothian Oil-Shale Formation

• Houston Coal
• various oil-shale horizons

Monktonhall Colliery was abandoned in 1997 and Blinkbonny mine adit was sealed in 2003 so bringing to an end a long history of deep-mining of coal within the coalfield. Opencast

Opencast

Opencast is a term to describe audio and video content, primarily in an academic context. It combines the terms "Open" for Open Source and/or Open Access and "Broadcast"...

ing has continued at various sites since then including Blinkbonny, Oxenfoord, Gourlaw and Newbigging Farm.