Drill cuttings are the broken bits of solid material removed from a borehole

Borehole

A borehole is the generalized term for any narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water or other liquid or gases , as part of a geotechnical investigation, environmental site...

 drilled by rotary, percussion, or auger methods. Boreholes drilled in this way include oil or gas wells

Oil well

An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.-History:The earliest...

, water wells, and holes drilled for geotechnical investigations or mineral exploration.

The drill cuttings are commonly examined to make a record (a well log) of the subsurface materials penetrated at various depths. In the oil industry, this is often called a mud log.

Drill cuttings are produced as the rock is broken by the drill bit advancing through the rock or soil; the cuttings are usually carried to the surface by drilling fluid

Drilling fluid

In geotechnical engineering, drilling fluid is a fluid used to aid the drilling of boreholes into the earth. Often used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells. Liquid drilling fluid...

 circulating up from the drill bit. Drill cuttings are separated from the drilling fluid by shale shakers

Shale shakers

Shale shakers are devices that remove drill cuttings from the drilling fluid that is used for boring holes into the earth. Controlling the solids in drilling fluid is an important component of the cost of drilling, so research into improved shaker design is ongoing.-Shale shaker design:Shale...

 (for liquid drilling fluid), or by cyclone separators (for air drilling). In cable-tool drilling, the drill cuttings are periodically bailed out of the bottom of the hole. In auger drilling, cuttings are carried to the surface on the auger flights.

One drilling method that does not produce drill cuttings is core drill

Core drill

A core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the core....

ing, which instead produces solid cylinders of rock or soil.