In 1796 he improvised a mechanised copper ore crusher at Wheal Friendship, a mine just outside Tavistock, Devon.

[1] This enterprise, also funded by the Martineaus, set out to produce vitriol, but as Taylor & Martineau became widely diversified.

This mine employed over 3,000 people and became the most productive in Cornwall, yielding almost 450,000 tons of copper ore.[11] He was also mineral agent to the Duke of Devonshire and to the commissioners of Greenwich Hospital.

[1] In 1824 he built the Redruth and Chasewater Railway to transport the ore from Consolidated Mines and others nearby to the port at Devoran.

[12] In 1836 he erected a new engine at Penrhyn Du and held a lease from 1838[13] In 1807 Taylor was elected a Fellow of the Geological Society, and acted as treasurer from 1816 to 1844.

In 1825 he was elected a Fellow of the Royal Society, and was one of the founders of the British Association on 26 June 1832, holding the office of treasurer till September 1861.

[1] A list of his publications may be found in the appendix of R. Burt, John Taylor, mining entrepreneur and engineer, 1779–1863, Moorland Publishing Company, 1977.