Fochriw Colliery was the prototype of the high capital investment made by the Dowlais Iron Company in large modern collieries which was to show a handsome return on capital during the following decades. A time came when production reached 1,000 tons of coal a day more than it consumed in the manufacture of iron and, therefore, it entered into the coal sales market in a big way.

The Fochriw pits were sunk at a greatly enhanced cost and during the first two years £26,589 was spent whilst during the next two years the expenditure fell to £14,330. However, from 1862 to 1865 it totalled £37,883.

When the No1 pit opened in June 1863, £62,063 had been spent and another £20,000 had been committed on the second shaft.

By September 1866 when the second pit came into operation, the total outlay in sinking and equipping the pits was an enormous £83,000 which was considered well worth spending and proved to pay handsome dividends in future years..

However, with the problems experienced, the management’s initial hope of good returns on expenditure were not realised but, by 1865, the return on capital invested was 10% which was considered a fair return for such an outlay.

The 1901 census showed that of the 1,500 employees at Fochriw Colliery, only about 275, approximately 18%, were resident in Fochriw

Fochriw No1 (North Pit - upcast)

The sinking of the No1 shaft which, on completion, was the deepest shaft in Wales, began in 1856 with the intention of working the four feet seam at a depth of 390 yards. Coal was reached in November 1862. However, the shaft was eventually sunk to a depth of 433 yards (1,299 feet*) with full production being achieved by June 1863.
(* from HMIM report of 1891)

A Dowlais Iron Company report dated 21 August 1863 advised  the depth of the shaft to be 374 yards (1122 feet).

The big coal seam of the No1 pit was originally thought to be about 7 feet thick. However, it turned out to be separated by a “thick clod” which resulted in only the upper 3 feet 6 inches being workable.

The photograph opposite shows the upcast shaft following its excavation by the Coal Authority as a result of infill settlement in April 2005.