Profitability
When recoverability is known in mining the resistance that a mineral or rock the reclamation work opposes. The recoverability of the masses decreases with increasing strength of the rock. The profitability has an influence on the position of the miners' property .
Basics
Every mineral mass offers a more or less great resistance to mechanical detachment from the mountain range. This resistance is mainly influenced by the hardness of the mineral and the cohesion in the mountain range. The hardness of the mineral or the type of mountain is the resistance that the mineral opposes to the penetration of a sharp or pointed toughness . The cohesion of the mountain range is the resistance that a piece of rock offers when it detaches itself from the mountain range. The cohesion is particularly influenced by the elasticity of the mineral and its fissures . The cohesion of the mineral is characterized less by its hardness than by the stratification of the mineral and the existing segregation surfaces as well as its cleavage.
Degree of profitability
The Freiberg mineralogist Abraham Gottlob Werner categorized the fossils according to their recoverability. They are divided into five classes: Rolled - mild - usable - firm - extremely firm.
"Rolling" is the term used to describe masses that have no actual or only a very slight connection between the individual parts. Such masses can only be moved by themselves to a small extent and with little effort. The rolling masses include sand , rubble and fossils that have already been extracted, such as ores , coal or mountains .
"Mild" is the term used to describe rock that is easy to crush. Such rocks do not lose their connection due to their own weight. The mild masses include rock salt , slate , roofing slate , chalk, dolithene lime, marl and gypsum. Furthermore rubble, which is connected by calcareous or ocred binders. In addition, hard coal and clay belong to the mild masses .
Rock that is quite strong is called "bräch". This rock has a dense and pliable fracture. Such rock is also referred to as "dashing". Fragile rock largely resists being crushed. The fragile rocks include serpentine , marble and ore-bearing rocks.
"Solid" means the degree of recoverability possessed by minerals that can only be obtained with great effort. Solid rock throws sparks with a steel tooth on impact. The solid rocks include magnet iron stone , dense brown iron stone, copper pebbles , granite, basalt and all ores that break into gangue masses of quartz and hornblende. In addition, graywacke, limestone and sandstone are among the solid rocks .
Rocks that offer the greatest resistance to processing are referred to as "maximum strength". The very firm rocks include pebbles , quartz and pebbly conglomerates , as well as very quartz-rich granites and porphyries .
Effect on extraction
The degree of extractability of a mineral or fossil has a great influence on the type of extraction work. This also influences the choice and use of the respective tack and other aids. Rolling masses can be processed using a shovel and scraper . Other tools are already required for the extraction of mild masses. These masses can be worked with the wedge pick , the hammer , the recovery iron and the crowbar . A wedge hoe is usually sufficient for extracting brittle rocks. But the toughness used in the extraction of mild rock can also be used. In some exceptional cases it is necessary to use blasting work. Solid and very solid rock can only be removed from the mountain range by means of drilling and blasting work . In early mining, firing was used to extract very solid rock .
Individual evidence
- ↑ a b c d e f g h Gustav Köhler: Textbook of mining science. 6th improved edition, published by Wilhelm Engelmann, Leipzig 1903
- ↑ a b c d e f Moritz Ferdinand Gätzschmann: Complete guide to the art of mining. Third part; The mining theory, published by JG Engelhardt, Freiberg 1846
- ↑ a b c d e Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, published by Julius Springer, Berlin 1908
- ^ A b c d e Gustav Leonhard: Fundamentals of mineralogy, geognosy, geology and mining science. JB Müller publishing house, Stuttgart 1852
- ↑ a b c d e f g Carl Stegmayer: Handbook of mining art for everyone. Publishing house by JL Kober, Prague 1862