DRILLING METHODS
- 2. 1. Definition 2. Objective of rock drilling 3. Classification of drilling 4. Brief description for each drilling methods 5. Drilling accessories
- 4. Exploration drilling for sample collected to estimate the quality and quantity of the mineral reserve Locates and defines economic mineralization Production drilling-in the mining cycle drilling performed for the placement of the explosives To generate under earth transportations and to allow locomotives In quarrying dimensions stone is freed by cutting channeling.
- 5. Auger drilling Reverse Circulation drilling Diamond core drilling Air core drilling Jumper bar drilling Jack hammer drilling Churn drilling Direct push rig Hydraulic rotary drilling Sonic drilling
- 6. Drilling is done with the helical screw Hallow stem auger-softer ground Solid fight auger-harder ground Geo chemical sampling at un consolidated material Portable Cheap & fast method Uncontaminated samples But poor penetration
- 8. Its similar to the air core drilling High pressure fluid forced down outer pipe and returns chips to surface up inner pipe Geochemical sampling in hard and soft rocks Samples(rock chips) of fresh rock in large amount rock Moderately priced & relatively cheap Quick & un contaminated Sample will contaminate below the water table
- 10. Diamond drilling utilizes diamond impregnated drill bits that attached in the end of the hallow drill rods. To get cylindrical core samples. It give whole rock sample and more geological information. Un contaminated high quality samples It can penetrate great depth. But expensive and slow method and small sample size water supply also required .
- 12. Hardened steel or tungsten blades are used to drill Three blades arranged around the drill bit The rods are hallow and contain inner tube That sits inside the hallow rod barrel Drill cuttings removed by injection of compressed air Geo chemical sampling into bed rock & it produce small chunks of cored rock More costly & slower than RAB method Minimal contamination but small sample size
- 14. There are manually operate drill used for making blast holes in stone and road material The drill is consist of 1 -1.5 inch in diameter and length between 2ft to 4ft Percussion is given by striking the drill manually by hammer The sludge removed from the hole with a scoop periodically The drill made of high carbon manganese steel bar
- 15. In mechanized mining pneumatic drills are worked by compressed air The principle involved is same that of manually operate jumper bar A popular variation of compressed air drill is jack hammer The air pressure of the drill is 800-1000 lbs per square inch
- 17. A portable drill rig using a bit fashioned on a massive steel cylinder that is alternatively lifted and dropped to a hole in earth and rock It used to drill into soft carbonate rocks of lead and zinc in hosted regions to extract bulk samples of ore A large version of churn drill is used in oil drilling is known as cable tool drilling
- 19. This technology is pushing or hammering without rotating the drill string Its not mean the drilling but it achieves the same result a bore hole Its limited and drilling in un consolidated rock & very soft material The speed and depth of penetration dependent on the soil type & weight of the power of rig It can produce a large number of high quality of samples quickly and cheaply Least penetration
- 21. Oil well drilling utilizes tri cone ;carbide embedded; fixed diamond impregnated drill bits bentonite & barite infused drilling muds to use to lubricate ;cool & clean the drill bit and control down hole pressure and stabilize the wall of the borehole it can pollute water and also causes dangerous fire risks So redundant safety systems & highly trained personnel are required to be implemented
- 23. Its works by sending high frequency resonant vibrations down the drill string to the drill bit Vibrations may also be generated within the drill head The frequency generated between 50 and 120 htz (cycle per second) Depend and varied by the operator Resonance magnifies the amplitude of the drill bit An internal spring system isolates these vibrational forces from the rest of the drill rig