logo comp4

100 300 T H Py Series Grinding Ball Mill For Mining Inry

Burrhstonehe cherty variety is frequently porphyritice the felspar imbedded in the mass decomposes, leaving the rock in a rough vesicular statef fine, it resembles thle burrhstone of paris and as it is exceedingly totugh and hard, it seems as if it was well adapted for grinding grains, orl might be used for mill.