The sinking of the pits was further affected by an Act of Parliament which made it illegal for any new colliery employing more than 20 men to have one shaft, and, at Fochriw, the mines inspector declared the No1 pit to be unsafe because only one pit was sunk in 1862.

Initially the shaft of No1 pit, which was fitted with rope cage guides, and operated double deck cages, was partitioned in the middle by brattice cloth in order to provide downcast air on one side and upcast air on the other. The danger of this method was disastrously demonstrated on Thursday 16 January 1862 when the single Hester shaft at Hartley in Northumberland was blocked when the beam of a Cornish pumping engine snapped and crashed down the shaft, demolishing the timber shaft divider screen and parts of the shaft lining. This accident entombing 204 miners below ground all of whom lost their lives.

The Act to Amend the Law Relating to Coal Mines – 7 January 1862, states that it was unlawful for the owner of a new mine to employ men to work a mine that did not have at least two shafts, or outlets, separated by natural strata not less than ten feet in breadth. Owners of existing single shafted mines had to comply with the new legislation by 1 January 1865 by providing a second shaft or outlet.

Mine owners had resisted previous attempts to pass such legislation on the grounds of cost. However, even after the legislation was enacted the owners could claim exemption against modifying existing pits if the expected remaining life of the pit was less than two years. Progressive exemptions were not uncommon since owners kept altering the life assessments of pits.

Fochriw No2 (South Pit - downcast. Also known as Rhos Glas  from Western Mail report dated 8 August 1885)

The 433 yard (375 yds, 1,126 feet*) No2 shaft, which was fitted with pitched pine cage guides, attained full production by September 1866. Both No1 and No2 shafts were brick lined and of an eliptical and not round construction.  (* from HMIM report of 1891). In the No2 pit, the upper 4 feet seam was entirely lost and was not reached until August 1866.

From an accident reported in the Merthyr Express on 3 November, 1866. A sinker named Thomas Buxton, aged 25 was ascending the air pit, and had nearly reached the top when his foot slipped, and he fell down a depth of 26 yards and was killed on the spot. This air pit may have been the fan drift which, at that time could not have been much more than 30 yards deep.

The plan opposite is of Fochriw No1 Pit and, although undated, probably shows the main roads as they were during the late 1880’s