1. Natural factors
The natural factors affecting the quantity and quality of coring are the physical and mechanical properties of the rock and the structure and construction of the rock seam. When drilling hard, dense, homogeneous and intact rock seam, the high rate is adopted, and the core is not afraid of scouring, not afraid of vibration, easy to get a complete rock core can keep the original structure; when drilling loose, broken, cut off, gum and soft and hard interlayer of the rock seam, take out the core of the rock is more blocky, granular, flaky, not only the original structure is destroyed, And the adoption rate is low, even cannot take out the rock mine heart.
2. Human Factors
2.1 Drilling Method selection is unreasonable
When the steel grains are drilled, the vibration is big, the hole wall clearance is big, and the Rock Mine talk, which is the biggest wear of the core, the wear of cemented carbide is slight and the diamond is minimized when drilling.
2.2 Structure selection of drilling tools is unreasonable
When drilling the core pipe, drill pipe, or drill bit, which is bent or eccentric, the drilling tool has a rotational motion, which produces centrifugal force and horizontal vibration, which causes the core to be destroyed by 揞 and abrasion. In addition, if suitable coring tools can be selected according to the nature of the rock strata drilled, it is possible to obtain a high rate of rock ore with good supply and availability.
2.3 Drilling Procedures Improper
(1) The pressure pressure is too high to aggravate the bending and vibration of the hole bottom drill, so that the core of the rock core is subjected to mechanical damage, and the pressure is not enough to slow the footage, which prolongs the time of the rock core to be destroyed in the Kondy heart tube.
(2) The rotational speed is too high, the vibration amplitude of the drill is increased, the destruction of the core is aggravated, the speed is too low, the drilling speed is lower, and the time of the Rock mine heart being destroyed is prolonged.
(3) The flushing capacity of the pump volume is too large, which aggravates the destruction of the core of rock mine and abrasion. The unreasonable circulation mode will also cause the rock and mineral heart to be washed and destroyed and repeated wear and tear.
2.4 Incorrect Operation method
Drilling blindly in the pursuit of footage, the return time is too long, the drilling is not timely, will increase the rock core in the hole at the bottom of the possibility of destruction; it is easy to cause the heart of rock to fall off when the lifting drilling tool is too strong or the method of coring is improper. The beating of the heart is prone to cause the crushing of the core and the upside down sequence, which affects the integrity of the core and distorts the level of the core.