A grizzly is a grid of iron bars that allows ore of the correct size to travel down the ore pass to the bottom of the mine, ready for hoisting to the surface.
A grizzly man's job was to break up the large rocks that were too big to pass through the grizzly bars. This is done either through using a sledgehammer, called a ‘big hit’, or by 'blasting' with explosives. The grizzly man had to make sure the grizzly was cleared and did not build up with large rocks, as it would affect wages.
Trammers would carry loose rocks and ground blasted out by the stoppers and developers. This is transported to the grizzly and the contents tipped out through metal chains. The smallest debris (10 inches or smaller in size) filtered through to the bottom of the mine. This ass then hoisted to the surface in skips to be processed in the mill to extract the tin ore. The larger rocks that could not be broken with a sledgehammer were 'blasted'. Mining protocol said that no more than 3 sticks of explosive were to be used on any one blast as it was thought a bigger explosion would break the bars of the grizzly. However, this rule was not always stuck to.
A grizzly man of Geevor, Ian 'Bomber' Davy remembers, "using explosives was an easier mehod of breaking them (rocks). I earned the nickname of "Bomber Davy"... I have myself blasted up to 15 or more which causes quite a large blast."