I can't see how a salt block could be legal but a mineral rock isn't. Salt is a mineral too. The rules for baiting are pretty general and don't specifically address mineral rocks or salt blocks. Click the attached link and scroll down to review the wording used for baiting. You might have a case if he said the salt block was legal but the mineral block wasn't. I do know a mineral blocks taste like a salt block.
http://www.outdooralabama.com/hunting/faqs.cfm
