The Old Three Foot seam in the Castlecomer Coalfield was discovered and mined on a relatively small scale in the 1640's. However, there seems little doubt that coal and 'culm 'were extracted in Castlecomer long before the discovery of the Old Three Foot seam, as Boate (1652) records that local Smiths had, for years, extracted 'little small coals' from outcrops in the Coolbawn area. The Ballycastle, Coalisland, Castlecomer and Kanturk Coalfields were all in significant production in the early part of the Eighteenth century, while the Arigna Coalfield was developed in the latter part of the century.

     In this seam  coal was found between 50 and 100 feet (33m) from the surface. It stretched in a wide bend from Doonane to Coolbawn and from Clogh to the foot of the Coolbawn hills. Because of the Coolbawn fault it is found again above the Coolbawn hills (the Rock Pit) but does not extend very far to the east. There was a high quality Anthracite and  it was easy to work because it was shallow. About 11 million tons of coal were taken out of this seam.

  THE JARROW SEAM

    It was about 80 yards wide and  in it there were about 124 men and boys  employed. About 1780 the Jarrow Seam was discovered. Mining became more developed . People got more explosives and had steam power for pumping. Pits were sunk from Doonane to Coolbawn. There were about seven Jarrow pits. In Doonane in 1740 the first steam engine was used to pump water from the mines. Steam driven fans to work the coal workings were first used at Jarrow Colliery at the end of the last century. Steam operated head gears for hauling coal and workers to the  surface, was first used at Montheen colliery at the beginning of the century. 

              The   seam  was   found    around   about   200 feet   below   the   three  foot. An interesting feature of  the  seam,  was, that  there  was a horse-shoe shaped  strip lying from Doonane to Moneenroe  and along to Coolbawn where the coal was much thicker and of better quality than over the area of each side. This strip of coal was known as the "Channel". The Channel coal was sometimes 4 ft thick where as the outlying coal was only 8-9 inches thick.

     " Jarrow" got its name from Jarrow coalfield in Durham. Pit sinkers were brought from Durham to work deeper pits in 1797. Some of these were not worked because of sulphur.

     Boneyarrow i.e." Jarrow Bawn" which was a pleasant village in its day, it had thatched houses. Most have now been replaced.

     The Skehana seam was about 300 feet deep. It was a good  quality and it was thought to be the best found in either England or Europe. However it did not extend very far. In the Deerpark an inclined shaft was sunk to the seam. This  was named the “Deerpark Pit” .The Deerpark Pit was part of the Skehana Seam . The Deerpark was worked from 1925 to 1969. Its deepest point was 700 feet from the surface. Altogether about eleven miles of underground roadways were built. Steam generators provided electricity. Later the E.S.B provided power and all electric current was supplied to the pit. There were three power lines coming at 38,000 volts. Then this was transformed for the use of machinery. 

We are told that from about 1945 machines were used for all the mining. Electric coal cutters were used underground, there were also conveyors, haulages and pumps. The pumps were pumping quickly as 60,000 gallons per hour were pumped. Coal was sorted, sized and cleaned after it came to the surface. This was done at the “Screens”. The miners baths were installed. It is said that these baths were the only proper miners baths in Ireland for quite a long time.

 Note: A ‘’Wash-Out’’

      At some time in the past when the coal was still vegetable matter, a lake or an old river flowed in, pushing out the material which could have become coal and laid down sand which became sandstone. This is common in coal-fields and a ‘’ wash-out ‘’may be quite small or very large. In the Skehana seam it was small.