3 Answers

There were many in N.W. Michigan. I've seen the remnants of them. There were some around Elk Rapids, Mich and Grayling , Mich.  And in the neighborhood of  Dead Man's Hill. That is a very senic veiw of a sort of Grand Canyon or valley from  very high up. It's steep and part of it was a land slide. It's beautiful in the fall.

according to one site hundreds of small mills....The DNR site mentioned three areas in MI that were effected by the lumber worker's strike around this time period but they did not state hoe many state mills there were.  The DNR site suggested trying the MI Historical Museum...I googled this and I believe you will need to write them. Or contact the DNR.

MICHIGAN'S LUMBER BUSINESS.; THE INDUSTRY EXCEEDS THAT OF ANY OTHER STATE.
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[ DISPLAYING ABSTRACT ]

DETROIT, Mich., Jan. 28.--The annual review of the lumber business of Michigan for 1885, but not including anything in the upper peninsular, or the Lake Superior region, as it is often called, shows that the lumbering industry of this State exceeds that of any other State in the Union.

This is from an article in the NY Times.  I couldn't get any more than this paragraph. Sorry