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Drilling has existed as an industry since the Chinese erected the first cable tool rig approximate-ly 4000 years ago.  Since the development of drill rigs, techniques and applications have led to the industry's expansion into the following eight specialized sectors:

Mineral Exploration
Blast Hole
Water Well
Oil and Gas

Drilling objectives
There is always a reason why holes are drilled within each of the industry sectors.  The reason for making a hole is called the drilling objective which consists of four important parts : statements, standards, conditions and checks.

The statements set out clearly what the objective is about.  It is important that the statements are clearly worded so they may be understood by the driller.  After all, he can not be expected to do a job unless he has a clear picture of what it is he's expected to do.  For example, Drill an exploratory hole to produce data on the nature and position of the formations; and produce chip samples for laboratory testing.

Standards tell the driller the precise requirements for the drilling.  Certain standards will be required for every hole and they must be adhered to exactly.  They are a measurement of the work performed. Examples of standards are :

* The hole to be drilled must be drilled within a 1/2  meter (18in) of the peg

* The hole must be drilled to a depth of 100 meters  (300ft.)

* Minimum hole diameter is to be 125mm (5 in)

* The hole must be within 3 degrees of vertical throughout.

* The sample interval is to be every 1 meter (3ft.)

* Drilling logs must record changes of formation within 0.2 meters (8 in) of correct    position.

The conditions provide the frame of reference for the work.  They describe how, when and where the standards apply.  Conditions may describe access to site or weather conditions and their affect on the drill site or hours of work.  Conditions could comprise the following :