# Use of Pyrotechnic Mixtures for Mining of Block Deposits
## 4 General Rules for the Application of Gas Generators in Mines  
Based on the in-field tests carried out thus far in mines located in various geological conditions, and on mining and geological conditions, general rules concerning the design and application gas-generating equipment have been defined.  
Gas generator prototype is intended for exploitation works, including loosening and shredding, rock detachment from massifs, monoliths, and block splitting. Conditions concerning insertion into holes apply only to dry holes between 28 mm and 105 mm in diameter. For holes with water content, it can only be used after the removal of water, and this requirement arose from the need to use wads of high quality, which cannot be used in holes filled with water. To use gas generator prototype for the extraction of aggregate material, the massif that is to be mined should have at least two vertical divisibility planes, and one horizontal.  
In the plane in which a body of material will be mined, blasting holes are drilled at diameters of 65 mm and a maximum of 115 mm. The distance between adjacent holes should be 75-90 cm (Figure 4), and their number depends on the length of the massif to be mined.  
To use gas generator prototype to extract stone blocks to obtain construction stone, the massif should have three outcropping planes (Figure 5).  
In the plane on which the monolith is mined, blasting holes are drilled at a diameter of 28 mm and a maximum of 45 mm. The distance between the adjacent openings should be 25-30 cm. When the massif is characterized by a small number of natural layers and fractures, then the distance between adjacent holes may be 30-45 cm, while the distance between the extreme holes and the massif edge should be 10-15 cm. Hole spacing depends on the strength of the rock and the structure of the rock mass. Distance between holes drilled from the bottom of the horizontal slot (natural plane) should be 10-20 cm (Figure 6). The number of holes depends on the length of the mined block.  
Figure 4: Diagram of hole spacing when mining aggregate material (Adapted from [16]).  
Filling the holes and calculating the gas generator active mass should be carried out in the following proportions:  
* For extracting aggregate: 150-200 g of pyrotechnic mixture per 1 m\({}^{3}\) of the mined massif rock mass,
* for block mining: 60-120 g of pyrotechnic mixture per 1 m\({}^{3}\) of rock mass of the mined block,
* for block detachment with three outcropping planes, one having been made with a diamond saw, with a small amount of cracks: 60-75 g pyrotechnic mixture per 1 m\({}^{3}\) of rock mass of the mined block,
* for massif detachment, with three outcropping planes, and two of them (one horizontal and one vertical) are integrated and have a natural slot with a small amount of cracks: 80-100 g of pyrotechnic mixture per 1 m\({}^{3}\) of rock mass of the mined block,
* for massif detachment, which has three outcropping planes, two of them (one horizontal and one vertical) are integrated and have a natural slot with a high amount of cracks: 100-140 g of a pyrotechnic mixture per 1 m\({}^{3}\) of rock mass of the mined block.