The use of waterpower in mining was widespread from early times to the 20th Century. Water was turned into power by means of big overshot waterwheels – some over 50 feet in diameter. The northern Ceredigion landscape was once dominated by these impressive water wheels turning lazily and driving a variety of rods, pumps, crushers and winches.
In the late 1800's it was possible to buy a water wheel “off the shelf” from the Greens foundry in Aberystwyth.None of the gargantuan wheels exist today - (unless a visit is made to the Llywernog museum where smaller wheels can be seen working) although the wheelpits and the infrastructure of lakes and leats required to keep the wheels turning can still be seen at key sites – giving some idea of how they must have dominated the landscape.
• In the early period of mining water was used for “Hushing”. A dam would be installed blocking a stream or reservoir at the top of a hill and when enough water was captured it would be released to scour the topsoil and scrub from a hillside.
• As time progressed, lakes were built to store water that could be released on demand to supply the waterwheels via a series of channels known as leats. Some leat systems run for many miles and would have required a complex signalling system to operate them. At some mines it was not uncommon for a man to leave the mine in the early morning opening the leat sluices and then return in the evening closing them.
• Smaller mines would generally use a single water wheel for pumping, crushing, and occasionally winding duties. Larger concerns would have several wheels; where one wheel serving the dressing floors would be situated down slope of another wheel serving a shaft so as to reuse the available water. Surplus water would be channelled to the separation process for washing the ore.
• The water wheel itself would be mounted in a solid masonry wheel pit with the crusher, usually of the roller type, securely mounted in the same construction. Power for pumping and winding would be taken from a crank on the opposite side to the crusher, with provision to engage and disengage the winder as required.
• The method of connecting the waterwheel crank to the pumps would vary according to distance and location. A power train would be constructed from lengths of timber and/or iron rods linked together and running on rollers set in the ground. These rigid power trains could run for some distance and power could be made to change direction both horizontally and vertically by means of rocking angle pieces.
• The Talybont deep adit for instance, had an underground shaft pumped by a waterwheel outside the portal. A run of rods, ran through the adit for over 500 yards resting on rollers set in the floor of the level, with angle pieces to take the power train round the turns.
• If the wheel was close to the shaft, a length of chain could be used, running on rollers mounted in dolly stands. One particular mine near Devils Bridge had an underground shaft accessed by an adit (drainage tunnel) that twisted and turned somewhat. The waterwheel was set into a masonry wheel-pit immediately outside the portal and used a steel cable fended off the walls of the adit by rollers where necessary.
• Iron rods were common in Wales for both the power trains and, for where pumping was done by single bucket lift, for the pump rods. In this instance the rods had to be inside the rising main.
• The pump would raise water through a rising main either to a cistern or to a collection launder where it would be run off, either at surface or through a drainage adit. Each section of rising main, together with its associated pump is known as a “lift”. The height of each lift, usually measured in fathoms (1 fathom = six feet) would be dictated by the required diameter of the rising main and depth of the shaft, deeper shafts would invariably have several lifts of pumps.
• There were two types of pump in use - the bucket pump and the plunger (or pole) pump.
• A bucket pump is in the form of a piston roughly resembling a bucket with a one-way valve in the middle, hence the name. (Some versions had two valves). This was also known as a drawing lift and would be mounted above a valve box known as a “clack box”. On the upward stroke the valve in the piston would be closed so water would be drawn upward, the lower clack valve would open allowing water to be drawn upward below the bucket pump from the sump at the same time. On the reverse stroke the piston valve would open and the water would fill the space above the lift, the clack valve being closed preventing water from flowing back into the shaft sump.
• Plunger pumps were also known as “pole pumps” being exactly what they resembled, and acted in downward direction forcing water through the valve box and up the rising main. These pumps would be used in conjunction with heavy timber pump rods fitted to the deeper shafts that required multiple lifts; however the pump in the sump at the shaft bottom would always be a bucket pump. Pumping by plunger pumps was done by the weight of the pump rods; the power of the engine or waterwheel was used for the raising of the rods not directly the pumping of the water.
• Engine shafts with over 600 feet of pump rods must have pumped by means of 3 separate lifts of pumps, the lower two raising water to a cistern from which it would then be raised by the next lift.
• Most shafts in Wales averaged only a few hundred feet, with a fairly small level of water. It was therefore possible in many cases to keep the mine dry with a single lift of pumps within a single cast iron rising main.
• Smaller diameter rising mains had less weight of water for a given height, therefore would place less load on the balance bob. A rising main of 6 inches diameter could support a column of water of up to 470 feet. Here, there would be a single bucket lift set into the bottom of the rising main above the valve box. The pump rods, in form of iron bars, would joint together by the use of box joint iron collars for ease of assembly and disassembly.
• The power from the waterwheel's crank would be in the form of a reciprocating backwards and forwards motion imparted to the flat rods. As all the pumping in this model was being done directly by the wheel, there would be the need for a balance weight to be applied to the reverse stroke of the rods. This would be applied both at the wheel and at the shaft collar, as it was important that the flat rods be kept under tension. The shaft collar arrangement would typically be in the form of an inverted T of timber construction known as a “balance bob”. It would have iron rods for reinforcement passing from the top of the upright, or “king” post, to the end of each outer beam. The end of one outer beam would connect to the top of the pump rod; the end of the other would carry the weight box, the end of the power train connecting to the top of the King Post, operating in a kind of see saw motion.
• In this arrangement the weight box is acting to balance the weight of the column of water in the rising main, and remember that a water wheel delivers power on both the outward and inward stroke of the power train. It is obvious from the above that on the lifting stroke the previously raised weight box will then be acting in favour of the lifting of the column of water in the rising main.
• In this single lift system , iron plates were often used as counterweights rather than a bulky weight box filled with rocks.