Quarrying of stones -Definition, various methods, and precautions
In this article, we will discuss the quarrying of stones by various methods and the precautions to be taken while quarrying and the selection of a suitable site for the quarrying process.
The common important terms used in quarrying are as follows:
1)Blasting: Quarrying with the help of explosives such as gunpowder or dynamite
2)Safety fuse: It is a wire consisting of short length and with burning composition
3)Tamping: The operation of filling the hole containing explosive with sandy clay
4)Quarry sap: It is the moisture present in the quarried Stone
5)Line of least resistance: It is the horizontal distance between the outside the surface of Rock to the hole of blasting
Methods of quarrying:
Quarrying is done by the following methods:
1)quarrying by hand tools
2)quarrying by channeling machine
3)quarrying by blasting
Quarrying by blasting is usually preferred than the two methods
In this, we will discuss quarrying by hand tools and quarrying by blasting
1)Quarrying by hand tools:
- Quarrying by excavating
- Quarrying by heating
- Quarrying by wedging
Also read the amazing topic: Dressing of stones (Commonly asked interview questions)
- Steel pin
- Quarrying by excavating: This method is suitable for soft rocks such as sedimentary rocks. The stones are obtained by the help of hammers, chisels, showels.
- Quarrying by heating: In this method, rock is heated using fuel and due to expansion rock cracks. The stones are obtained by pickaxes, showels, etc
- Quarrying by wedging: This is one of the usually preferred methods than the above methods.
In this method number of holes is drilled on the surface of the rocks in an alignment. The diameter of the hole is about 12 mm and death about 100 to 200 mm at a uniform distance of 100-150mm.
This method of quarrying is suitable for sedimentary rocks and also for soft rocks.
Watch this video for a better understanding:
2) Quarrying by channeling Machine:
3) Quarrying by blasting:
This method is for hard and compact rocks and for large quarrying process. In this method, a large rock is separated by the use of explosives.
The following equipment is used for blasting:
- Priming needle
- Scrapping spoon
- Tamping bar
- Copper cylinder
Also read: Deterioration of stones
Operation process for blasting:
1) The blast holes are made with the help of jumpers, dippers, and spoon.
2) Then clean the blast holes with the help of cloth
3) The quantity of explosives(i.e gunpowder or dynamite) is poured into the hole
4) Has shown in the figure the remaining portion is filled with clay or
5) The brimming needle of a 2 mm diameter is inserted to reach the gunpowder. Then it is slowly withdrawn leaving narrow space.
6) A fuse is introduced in the narrow space.
7) The free end of the fuse is fired with a match stick or with electricity.
8) Finally, an explosion takes place and the rock is disintegrated into small stones that are used for engineering purposes.
Here is the more brief Detail About the Blasting operation, It is carried out as follows:
(i) Blast holes of required depths arc made with jumpers, dippers and scraping spoons. To convert dust into the paste a small quantity of water is added to make the rock soft. Such paste is easily removed by scraping spoons.
(ii) Blast holes are cleaned. They are made dry and clean by a small iron rod tied with a rag at its end.
(iii) The charge of gun powder or dynamite is placed at the bottom of the hole. The priming needle which is a thin copper rod is placed in position. It is to be coated with grease so as to make its withdrawal easy.
link is formed between the fuse at top and charge
(iv) The remaining portion of the blast hole is filled with damp clay or powdered stone. It is to be rammed hard. Ramming is done by a copper tamping bar. When tamping is being done, To ensure easy removal of priming needle it is turned so that it can be easily removed when the hole is completely filled up.
(v) Priming needle is taken out and the space formed by it is filled with gun powder or dynamite as
shown in fig. 1-10.
(vi) A fuse is inserted in the hole and is kept projecting about 15 cm to 20 cm above the rock surface. Thus a link is formed between the charge of explosive at the bottom and the fuse at the top Detonators are used when the explosive is dynamite.
(vii) The free end of the fuse is fired. This can be done either with a match or with electricity. Firing by electricity has the following advantages:
(a) It ensures safety.
(b) It results in the saving of time and labor.
(c) Firing is simultaneous and hence, the efficiency of explosives is greatly increased.
(d) It is useful for firing fuse underwater.
(viii) The explosion takes place and rock is disintegrated into small blocks. Such blocks are collected and taken for further treatment.
Precautions to be taken in blasting:
- The blasting area boundary should be with caution boards, red flags, etc.
- The tamping bar should be of copper and not steel.
- Blasting should be carried out by a trained and experienced person.
- The fuse should be longer so that it can escape from the area.
- The explosives should be stored properly.
Selection of the site for quarry:
- The site should be so selected that the power, materials, and labor should be available near the site.
- The distance of the Quarry site should be minimum for the transportation facilities.
- The site so selected should be economical.
- Facilities such as tractor, trucks, JCB should be available for carrying stones.
- There should not be any Radioactive Rays in the site.
- The site it should be from residential areas.
- The site should be such that it should not cause disturbance to the people residing near the site.
- Space for disposal should be available near the site.
Machines for quarrying: Used are
A list of machines commonly employed in quarrying is :
1) Cableways and ropeways: To hoist and transport stones.
2) Channeling: To form long narrow channels in the rock
3)Crushers: so as to take out massive blocks of stones. To break large stones into small size
4) Drilling machines: To drill blast holes.
5) Molding machines: To form moldings on stones.
6) Polishing machines: To polish the surface of stones.
7) Pulley blocks and cranes: To lift stones.
8) Saws: To cut stones into desired shapes and sizes
9) To sort out stones according to sizes and grades.
10) Tipping wagons: cars, dumpers, etc.: To transport the materials from the quarry.