Methods of Quarrying Stones: Tools and Techniques
🏗️ Methods of Quarrying Stones: Tools and Techniques
Quarrying is the process of extracting high-quality stones from natural solid rock formations. Unlike mining, which deals with minerals like coal or gems, Quarrying specifically refers to extracting building stones exposed to the surface.
As a civil engineer, understanding the method of extraction is vital because it determines the shape, strength, and final use of the stone.
1. Excavation using Hand Tools
This is the traditional method, best suited for soft stones or when specific block shapes are needed for masonry.
Digging & Cutting: Used for soft stones like Laterite. Tools used include pickaxes, shovels, and chisels.
Heating: Fire is used to heat the rock surface. The differential expansion causes the upper layer to separate from the lower one.
Wedging: Used when natural cracks are present. Steel wedges are driven into cracks to split the rock. If cracks are absent, holes (10cm dia) are drilled, and conical steel plugs (feathers) are driven in to create a split. This works excellently for Marble, Limestone, and Sandstone.
2. Quarrying by Channeling Machines
This modern method is used for large-scale extraction of solid rocks like Granite. It requires at least one face of the rock to be exposed.
Process: The machine (powered by electricity or compressed air) cuts deep channels (up to 240-370 cm depth).
Horizontal Splitting: Once vertical channels are cut, horizontal holes are drilled at the bottom. Wedges are then driven in to lift the massive block.
Use: Ideal for producing large slabs for flooring or export.
3. Quarrying by Blasting
This is the most common method for producing Stone Aggregates (Gitti) for roads and railways. It shatters the rock into irregular pieces.
Materials Used in Blasting:
Gunpowder: A mixture of charcoal, saltpetre, and sulfur. It produces larger blocks and is ignited using a Cotton Fuse Wire (burn rate: 1cm/sec). It cannot be used underwater.
Dynamite: A high-velocity chemical explosive used for shattering rocks into small pieces (aggregates).
Detonators: Small copper cylinders containing mercury fulminate. They are used to trigger the main dynamite explosion, often via electric circuits for precise timing (essential for tunnels or demolitions).
📊 Comparison: Gunpowder vs. Dynamite
| Feature | Gunpowder (Barood) | Dynamite |
| Effect | Produces large blocks | Shatters into small pieces |
| Best For | Building Blocks | Aggregates & Tunnelling |
| Cost | Cheaper | 4-5 times more expensive |
| Safety | Safer to handle | Requires licensed expertise |
Building Materials
Building Materials: Stone and Brick
Part 1: Stones and Rocks (पत्थर और चट्टानें)
Classification of Rocks and Their Uses: Geological, Physical, and Chemical classification (Igneous, Sedimentary, Metamorphic).
Common Building Stones: Characteristics and specific uses of Granite, Marble, Limestone, and Sandstone.
Quarrying of Stones: Methods of extraction (Blasting, Wedging) and essential tools/materials.
Criteria for Selection of Stones: How to choose the right stone based on strength, durability, and appearance.
Deterioration and Preservation: Why stones decay and how to protect them during construction.
Artificial Stones & Stone Veneering: Classification based on texture and man-made stone alternatives.
Laboratory Tests on Stones: Physical tests like Crushing strength, Water absorption, and Hardness test.
Part 2: Bricks and Clay Products (ईंटें और मिट्टी के उत्पाद)
Brick Earth and Manufacturing: Composition of good brick earth and the step-by-step preparation process.
- Chemical Changes and Dimensions: Changes during the burning process and standard dimensions (19cm x 9cm x 9cm).
- Special Purpose Bricks: Heavy-duty bricks, storage methods, and weight of brickwork.
- Special Shapes and Lightweight Bricks: Perforated, hollow, and light-clay bricks for modern construction.
- Alternatives to Bricks: Fly ash bricks, sand-lime bricks, and their various types.
- Testing of Bricks: Compressive strength, Efflorescence, and Soundness tests.
Part 3: Concrete Blocks (कंक्रीट ब्लॉक)
Use of Concrete Blocks: Application in masonry and comparison with traditional brickwork.
Manufacturing and Storage: Production process, standard measurements, and tips for site storage.
Testing of Concrete Blocks (IS 2185): Understanding Indian Standard requirements for quality control.
Part 4: Binding Materials (Laying aur Plastering ke liye)
Cement: Manufacturing (Dry and Wet process), Chemical composition aur hydration of cement.
Types of Cement: OPC (33, 43, 53 grade), PPC, Rapid Hardening, aur Low Heat cement ke uses.
Field & Lab Tests on Cement: Color test, Fineness test, Setting time (Initial & Final), aur Soundness test.
Lime (चूना): Classification (Fat lime, Hydraulic lime), slaking process aur purane constructions mein iska mahatva.
Part 5: Timber and Wood Products (लकड़ी और इमारती लकड़ी)
Classification of Trees: Exogenous aur Endogenous trees; Hardwood vs Softwood.
Structure of Timber: Pith, Heartwood, Sapwood, aur Cambium layer ki pehchan.
Seasoning of Timber: Natural aur Artificial methods (Kiln seasoning) taaki lakdi tedi na ho.
Defects in Timber: Knots, Shakes, aur Decay ke karan aur unse bachav.
Industrial Timber: Plywood, Particle board, Veneers, aur MDF ka modern use.
Part 6: Mortar and Concrete (मसाला और कंक्रीट)
Mortar: Proportioning of Sand and Cement, workability aur masonry mein iska role.
Concrete Ingredients: Aggregates (Coarse and Fine), Grading of aggregates aur water-cement ratio.
Properties of Fresh Concrete: Slump test, Compaction factor, aur Segregation/Bleeding kya hoti hai.
Admixtures: Concrete ki setting speed badhane ya ghatane wale chemicals.
Part 7: Miscellaneous & Modern Materials (विविध और आधुनिक सामग्री)
Ferrous and Non-Ferrous Metals: Steel (Mild steel, TMT bars), Aluminum aur Copper ka construction mein use.
Glass and Plastics: Types of glass (Laminated, Tempered) aur PVC pipes ki properties.
Paints and Varnishes: Composition of paints, types of distempers aur iron/wood surfaces ki painting.
Damp Proofing Materials (DPC): Bitumen, Mastic asphalt aur waterproofing compounds.
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