The fundamental problem in rock working is the breakage of fragments out of the face of a solid rock wall rock. Mechanically. this can be done only by forcing a tool into the rock surface. after the manner of an indenter is commonly used in the testing of surface hardness. https://safeersappliancers.shop/product-category/neff-n50-ki5852sf0g-integrated-50-50-fridge-freezer/