In this article, effects of moisture content and coal mixtures on grinding properties of the samples of two different fine coals, which were used in the Golta Cement Factory in Isparta (Turkey) were investigated. Grinding tests were done in a new grinder called Mortar Grinder. A good calibration has been established between the Mortar Grinder with the Bond and the Hardgrove grindabilities at the beginning of the tests. At the first stage, A and B type two coal samples, and in the second stage, the samples of three different mixtures (25% of A + 75% of B, 50% of A + 50% of B, and 75% of A + 25% of B) have been worked in grindability tests for different moisture contents. As a result, although the A and B coal samples were showing different grinding intervals versus moisture contents, these samples had similar grinding characteristic curves. Additionally, the high quality coals have easier grinding in respect to the low quality coals with the same moisture content.