[Cranky When Wet]

Rotating drums immediately brings to my bunny mind a Lapidary tool.

Lapidary is the art of cutting rough rock into gem stones. Normally, rotating/grinding machines are used for the process.

A less-formal method involves using various sizes of rotating, plastic-lined, drums for polishing rock.... it's a good method for teaching kids how to polish semi-precious gems since the machines are much safer.

Drums can range from one pound capacity to any size you want (i.e. 10, 20, and commercial sizes beyond that).

The trick will be to automate how the salt is dispersed.

I suggest speaking with the Calgary Rock and Lapidary Club. They could direct you to people who could help you see these units in operation and even to buy a machine if someone is no longer using theirs... Here's the link: http://www.crlc.ca/index.htm

Hope this helps and will look forward to hearing your success :-)

Bunny