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It was invented independently in Switzerland and the United States. [1] It resembles a specialized kind of milling machine that provides tool and die makers with a higher degree of positioning precision (repeatability) and accuracy than those provided by general machines. Although capable of light milling, a jig borer is more suited to highly ...
Reaming itself can be conducted either in an existing borehole ("pilot reaming") or during the drilling operation ("reaming while drilling"). Underreaming is primarily used to allow a wider clearance for running and cementing the casing correctly, either due to restrictions (swelling shales, tortuosity) or to be able to run a larger casing size.
The drill cuttings from the reamer head fall to the floor of the lower level. The finished raise has smooth walls and may not require rock bolting or other forms of ground support. [ 1 ] One impressive use of raise boring is the 7.1 m diameter shafts for Sasol's Middelbult and Bosjesspruit Mines in South Africa.
The continuous use of a coolant stream during the reaming process has been shown to consistently (75% of the time) result in hole sizes that are 0.0001 in. (0.0025 mm) larger than the reamer itself, with a process spread of +/- 0.0002 in. the remainder of the time. Similarly, using a semi-wet reaming process often results in hole sizes that are ...
[1] Although often used interchangeably, the terms directional boring and horizontal directional drilling are distinct in that they convey a different sense of scale. The term "directional boring" or "bore" is generally reserved for mini/small sized drilling rigs, small diameter bores, and crossing lengths in terms of hundreds of feet.
A part's-eye view of a boring bar. Hole types: Blind hole (left), through hole (middle), interrupted hole (right). In machining, boring is the process of enlarging a hole that has already been drilled (or cast) by means of a single-point cutting tool (or of a boring head containing several such tools), such as in boring a gun barrel or an engine cylinder.
Drill cuttings [1] are broken bits of solid material removed from a borehole drilled by rotary, percussion, or auger methods and brought to the surface in the drilling mud. Boreholes drilled in this way include oil or gas wells , water wells , and holes drilled for geotechnical investigations or mineral exploration.
K.S. Tom describes the drilling process: "The Chinese method of deep drilling was accomplished by a team of men jumping on and off a beam to impact the drilling bit while the boring tool was rotated by buffalo and oxen." [4] This was the same method used for extracting petroleum in California during the 1860s (i.e. "kicking her down").