Over the past 300 years, Renfrewshire had many coal and limestone workings. It also had a number of less common, though more valuable minerals, including copper. Copper occurs in veins among the lavas of the Renfrewshire hills, along with Barytes, which was worked at Muirshiel. Hundreds of tons of copper were worked, and many more trials (speculative shafts and tunnels) opened up for copper on the fabled ‘Lochwinnoch vein’, which ran north from Lochwinnoch via Kilmacolm to Gourock.
The earliest copper mines were above Gourock from the 1760s, owned by the Stuarts of Castlemilk. In 1782 this mine was described as being run by a respectable company from England and was doing very well as the copper was of a good quality. When the ore was dug out it was ‘broke into small pieces, washed, then strained and separated using mercury’. At least three workings are shown on a map of 1796. Water was required for power and dressing, but was also a problem when keeping the mines dry. A dam and water powered engine was constructed on the Gourock Burn to pump water out of the mines and to wash and process the ore. The mines declined, but were explored and reopened again several times, including in the 1860s. The occurrence of copper generated further trials in the area. Interest was reignited if the price of copper rose on the world market.
The second copper mining area was above Lochwinnoch. Brian Skillen’s article in RLHF Journal Vol 8 covers numerous copper mines and trials in the Calder valley, and its tributary the Kaim Burn. The lowest successful mine was on the west bank of the Calder just upstream of Bridgend. Its success generated a number of trials upstream towards Little Cloak. The best known and longest lived workings were at Kaim, where copper was found in the 1830s. Again success was limited, but more productive workings commenced in 1860s with an engine house and chimney stack. Several hundred tons of ore were produced, but the company was wound up in 1863. However the workings were reopened soon after and further mines and drainage levels driven and worked to 1870. Higher up Calder Glen, various trials were driven from the river valley in the 1860s. Small scale working around Clovenstone failed in 1865. The final workings at Kaim in 1874 went down more than 60 metres, but again were short lived.
When the railway was constructed from Bridge of Weir to Kilmacolm, copper was found in one of the cuttings, but was not rich enough to make working economic.
Overall, copper was a valuable mineral and attracted ongoing interest in Renfrewshire, especially when the price rose. Old workings were a focal point of interest, as they provided ready access to copper veins, without the expense of building new shafts. However starting a copper mine and its processing plant was capital intensive and unless productivity was high, failure was always likely.
© 2015 Stuart Nisbet