History never is simple; which is a good thing. When and where was the copper crusher (Cornish rolls) invented? A simple question, but with two answers.
Two tales of invention
Tale 1 The Wheal Friendship story
“In 1796, John Taylor improvised a crushing machine (Cornish rolls) at Wheal Friendship in Devon from two discarded pump main pipes….” Bryan Earl, Cornish Mining
Take 2 The Wheal Crowndale story
” the first ever roller crusher was created in 1808 in Devon at Wheal Crowndale copper mine near Tavistock, then managed by John Taylor. His experimental machine was water powered and apparently used two pieces of cast iron rising main (pumping pipes), but chilled cast iron became the standard material, due to the considerable force needed to crush the mineral.” Industrial Archaeology of the Tamar Valley Research by Robert Waterhouse FSA, assisted by the Morwellham Archaeological Group, 2002-2010.
None of the many books on my shelves that cover the invention include both stories, and Roger Burt in his biography mentions neither, so which one is correct?
A possibility exists that both are, that is the young Taylor played around with pump mains at Friendship to arrive at a working model, and once the concept was proven built his first productive crushed at Crowndale.
Although this of this chain of events makes sense, it leads to the conclusion that John was involved with Wheal Friendship two years before that fateful day when he was offered its management. It means that at the age of 17 he was already tinkering away with engineering ideas at the mine, if so it makes that blatant act of nepotism of 1798 (see earlier post) less surprising then it first appears.
The importance of the invention
Tin and copper ore demand different dressing floors to release the wealth from the rock. Tin dressing floors were packed with machinery, copper floors full of women and children. This was a difference enforced by the nature of the minerals.
Tin was dense, and could be liberated by stamping the rocks to a sand that was then separated from the waste rocks in a wide range of buddies, pits, frames, shaking tables, and other assorted devices that relied on it being denser when suspended in water.
Copper was lighter and had an unfortunate tendency to break into too fine particles under the heads of stamps. The two characteristics resulted in too much ore escaping the system if the rock was stamped. Copper ore was therefore treated by a series of processes such as bucking, cobbing and spalling. All processes that described hitting the rocks with hammers.
John Taylor’s achievement was to replace part of this manual intensive work with a machine. A machine that took lumps copper ore and crushed it to a smaller size, but without causing large losses that a set of stamps would cause.
How the crusher operated
Like all good inventions, Taylor’s design was simple. Ore was fed from a hopper between the two rolls, which were geared to turn inwards against each other, crushing the ore. A weighted arm was used to maintain the correct pressure on the rollers. The concept was similar to one used on apple crushers, perhaps they were the inspiration for his invention.
The next stop on this wander around John Taylor’s life will take this blog far away from the Devon countryside into the depths of the Welsh Mountains.