In 1832, the Hanbury family of Pontypool, in Gwent, South Wales, sank a small pit we know as 'The water Balance Pits' near Blaendare, on the Upper Race. This was done to improve the supply of coal to the family's rapidly expanding industries in the area. These consisted of blast furnaces coke ovens forges, rolling mills, also brick-making and the mining of ironstone. As these industries expanded, so the need for more fuel became evident, this then necessitated the sinking of another mine, this time using the power of steam as opposed to water. At the same time, it helped create an industry for supplying coal in the locality and played its part in the fuel needed for the rapidly expanding age of steam around the world.

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The Glyn pits were sunk to a depth of 190 yards using the  Rotative Beam Engine, which is still in situ as it was when erected in 1845. A stone plaque, built into the wall of the pump house carries the initials C.H.L 1845, which are the initials of Capel Hanbury Leigh, and the date of installation. C. H. Leigh ran the Glyn Pits until it changed hands in 1852, leased to a three-man partnership, where little changed on-site until it changed hands once again in 1855, this time to a four-man consortium, comprising  Darby, Brown, Robinson, and Lewick. (The name of Darby being synonymous in the making of iron) These four men were to become the core of the Ebbw Vale Steel, Iron, and Coal  Co. At the change of hands in 1852, an inventory was drawn up which shows that the Vertical Steam winding engine was not on-site at that time. The inventory confirmed that two shafts, and the Rotative Beam Engine, along with its chain sheaves for winding were present. The Cornish practices of that period were to firstly install a beam engine, to serve the dual purpose of both winding and pumping until sufficient reserves were proven, which would then warrant a separate winding engine. Together with the evidence of the 1852 inventory, and the fact that in a magazine, 'Le Tour Du Monde' or 'A Tour of the World' dated 1865, has a drawing of the Vertical Winder House which shows it was on-site at that time, then it is safe to say it was erected between those dates.  Several books have been written suggesting that both engines were made at the Neath Abbey Iron Works. We cannot be certain of this, for no makers name has been found on either engine to date. But a 30-inch rotative beam engine was built for  C. H. Leigh by the Neath Abbey Co.in 1845, and it is assumed that it was the one for the Glyn Pits, but when it comes to the Vertical Winding Engine no evidence has been found to date, nor is it mentioned in the papers of the Neath Abbey Iron Works, to suggest it was made by them.

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During the working life of the Glyn Pits, which was until 1932, 69 miners were to lose their lives, 5 of which still rest at this mine to this very day.  In January of 1890, a double tragedy was unfolding here for a fire was raging underground, and indeed was to see management decide to breach a reservoir containing 760 cubic yards of water allowing it to cross the intervening ground and to pour down the up-cast shaft in an attempt to put out the fire but sadly to no avail. Because of the effects of fire and flood, some of the miners were transferred to the Llanerch Colliery a few miles away, where around 10 days later a massive explosion ripped through that mine, killing 176 men and boys, of which the youngest was twelve years old. --" Among them were some of the men from  Glyn Pits "  

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Today a window can be found in Trevethin Church, Pontypool to the memory of the 181 who died in both of these terrible disasters.

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The Glyn Pits are now recognised as a Monument of National Importance. The main reason for this recognition is that it is the only one left with the engines Etc left In Situ and that the Vertical Winding engine is possibly the only one of its type left in the world.

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Since abandonment, the mine has been handed back to the Hanbury family, where it all started almost 175 years ago.