Methods of quarrying stone
Methods of quarrying stone:
The rocks suitable for the manufacture of stone materials are called useful minerals and operations
Known as mining involved in getting minerals.
In the mining process, the voids formed are called excavations, and the mining deposits are quarries.
The purpose of quarrying is to obtain stones for various engineering purposes.
However, Knowledge of various quarrying methods is essential but does not make one highly capable of selecting or specifying stone for building work.
Therefore, Depends on the nature and surface of the rocks and their purpose Stones are needed, quarrying is done by excavation, wedge, heating, or explosion.
Excavation
Stones buried in the ground or under loose loads are excavated by pickaxes, crowbars, chisels, hammers, etc.
Wedding:
This method of quarrying is suitable for expensive, soft, and graded rocks such as sandstone, limestone, laterite, marble, and slate.
However, Holes about 10-15 cm deep, about 10 cm apart, are made perpendicular to the rock. Steel pins
And wedges or plugs (conical wedges) and feathers (flat wedges) as shown in Fig. 3.4 They are.
The aftermarket system of plugs and feathers is fine. These plugs are then fired simultaneously
With a sled hammer. The rock slab splits along the least resistance lines through the holes.
However, In the case of soft rocks, dry wooden pegs are poured into the holes, and water is poured on them. The pegs swell and exert pressure, causing the rocks to crack along the line of holes.
Then, the wedges are placed in the cleft plane (two layers of joint) on the exposed face of the rock and hammered.
Therefore, The slab is completely detached and extracted with the help of crowbars and rollers. In this method, the waste is minimal and the required size and shape slab can be quarried.
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Hot
Small, thin, and regular stones are best suited for quarrying with rocks such as granite and Nice.
A pile of fuel is piled on the rock surface in a small area.
However, Two successive layers of rock are separated by the uneven expansion of the two layers. The loose rock sections are broken into pieces of the desired size and removed with the help of pick-axes and crow-bars.
Moreover, The obtained stone blocks are therefore very suitable for coarse clay stones. Sometimes, the intermediate layers must be separated from the upper and lower layers. In such a case, the intermediate layers must be separated from the upper and lower layers.
In such a case, the intermediate layer is heated and the expansion separates it from the other two.
Blasting
Explosives such as blasting powder, blasting cotton, dynamite, and cordite are used. The operations involved are boring, charging, tamping, and firing.
Boring
The holes in the rock are drilled or drilled. For vertical holes, a jumper is used, but for inclined or horizontal holes, boring bars are used.
However, A person will hold the jumper exactly where the hole needs to be made. The other person pushes it up and down and flips it at once.
However, Water is regularly poured into the hole during the operation to soften the rock and facilitate drilling. The clay paste produced during the process is removed from the pores by scraping. For hard rock, machine drilling is used instead of manual drilling.
Moreover, Is being charged The holes are completely dried and the required amount of charge is placed in the holes.
To dry holes, the rag is tied in a scraper and moved in the hole, which absorbs moisture.
If there is water leaking in the hole, the hardness of the water inside the hole is ensured.
Tamping
After placing the charge in the hole, the greased priming needles are placed in the hole slightly outside the hole, then tamped with a brass tamping rod in layers of damp clay or stone dust.
However, Priming needles should be kept rotating while tamping is done. This is done to keep the needle loose in the hole.
Moreover, Priming needles are then extracted and 60 to 75 percent of the space created by pulling the needle is filled with gun powder. The Bickford fuse, a small cord of tar-coated cotton, is placed to touch the needle.
Moreover, The other end of the fuse is placed long enough so that the person carrying it can go to a safe place. Blasting powder and cordite are ignited using a fuse, while the gun is blasted with cotton and dynamite.
Precaution in the explosion
Accidents may occur during the explosion. Some of the following points to note:
1. Blasting should not be carried out late in the evening or early in the morning. Blasting The bells must be made public and the siren workers and nearby public be warned It is timely to retire to a safe distance.
2. The danger zone, the area of about 200 m radii, should be marked with red flags.
3. First Aid Show Will be available.
4. Number of charges filed, a number of blasted charges and misfires Is documented.
5. Explosives should be collected and handled carefully.
6. Detonator and explosives should not be held together.
7. Cartridges should be handled with rubber or polyethylene gloves.
8. A maximum of 10 tube blasts at a time that is also continuous and not Simultaneously.
Explosives used in quarrying
The composition and characteristics of various blasting powders and their suitability are given in Table 3.4.
Collection of explosives
Explosives should be stored in a magazine (a special type of building) which should be kept away from residential areas, petrol depots, etc. The magazine should have high-level ventilators and hide the wiring.
However, It should be protected from lightning. No smoke or fire should be allowed in the nearby area. Explosives must be protected from extreme heat or cold and from moisture.
They should be handled with care and flexibility. The newspaper should be surrounded by barbed wire and restricted access.
The number of explosives required
The amount of explosives required depends on several factors, such as the power of the explosives; the Blasting method; the Number of boreholes – their size, position, etc.
However, And the type and mass of the rock to be ejected. It is very difficult to include all the elements in the expression and get exactly the explosiveness required. A rough estimate can be made of:
Where
A = Gun Powder or Dynamite Quantity (g)
L = minimum resistance line length (m)’
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