The heyday for Morwellham Quay came when the huge copper deposits were discovered at the Devon Great Consols just 4 miles to the north in 1844. £1 shares were soon worth £800 as the rush to extract the ore started. This gave rise to Morwellham's fame as the "richest Copper port in Queen Victoria's Empire"
For a detailed account of the copper ore trade see Peter H. Stanier's paper "The Copper Ore Trade of South West England in the Nineteenth Century".