INSTRUMENT FOR TESTING THE COMPACTNESS OF ROCKS BY THE PROTODIAKON METHOD
The compactness of a rock is a characteristic that characterizes its resistance to separation of fragments from it by tools or impact. The compactness of a rock depends primarily on its composition, homogeneity, grain size, on the quality of the binder and, to some extent, on its hardness.
The compactness of a rock is determined by the compactness index, denoted by the letter f. The Protodiakon classification, which has to do with compressive strength, is commonly used.
The Central Mining Institute (GIG) has developed compactness indices for coals. According to this classification, coals are divided into five classes:
- Class I - f = less than 0.40 - coals that are particularly easily workable,
- Class II - f= 0.41 to 0.80 - coals that are very easily workable,
- Class III - f = 0.81 to 1.40 - easily workable coals,
- Class IV - f = 1.41 to 2.40 - coals difficult to machine,
- Class V - f = above 2.40 - coals very difficult to work.
Values of compactness coefficients of rocks according to Protodiakonov.
Kategoria | Stopień twardości skały | Rodzaje skał | Wskaźnik związłości |
|---|---|---|---|
VIII | Skały ziemiste | Ziemia roślinna, torf, lekkie grunty gliniaste. | 0,6 |
IX | Skały sypkie | Ziemia nasypana, węgiel wydobyty. | 0,5 |
X | Skały ciekłe | Kurzawki, grunt błotnisty, less rozrzedzony i inne grunty rozrzedzone. | 0,2 |