Mining Glossary D

Day order - An order to buy or sell shares, good only on the day the order was entered.

Debenture - See bonds.

Debt financing - Method of raising capital whereby companies borrow money from a lending institution.

Deck - The area around the shaft collar where men and materials enter the cage to be lowered underground.

Development drilling - drilling to establish accurate estimates of mineral reserves.

Decline - A sloping underground opening for machine access from level to level or from surface; also called a ramp.

Deferred charges - Expenses incurred but not charged against the current year's operation.

Depletion - An accounting device, used primarily in tax computations. It recognizes the consumption of an ore deposit, a mine's principal asset.

Depreciation - The periodic, systematic charging to expense of plant assets reflecting the decline in economic potential of the assets.

Development - Underground work carried out for the purpose of opening up a mineral deposit. Includes shaft sinking, crosscutting, drifting and raising.

Diabase - A common basic igneous rock usually occurring in dykes or sills.

Diamond - The hardest known mineral, composed of pure carbon; low-quality diamonds are used to make bits for diamond drilling in rock

Diamond drill – a rotary type of rock drill that cuts a core of rock that is recovered in long cylindrical sections, two cm or more in diameter.

Diamond driller - A person who operates a diamond drill.

Dilution (mining) - Rock that is, by necessity, removed along with the ore in the mining process, subsequently lowering the grade of the ore.

Dilution (of shares) - A decrease in the value of a company's shares caused by the issue of treasury shares.

Diorite - An intrusive igneous rock composed chiefly of sodic plagio-clase, hornblende, biotite or pyroxene.

Dip - The angle at which a vein, structure or rock bed is inclined from the horizontal as measured at right angles to the strike.

Dip needle - A compass with the needle mountcd so as to swing in a vertical plane, used for prospecting to determine the magnetic attraction of rocks.

Directional drilling - A method of drilling involving the use of stabilizers and wedges to direct the orientation of the hole.

Discount - The minimum price below the par value at which treasury shares may legally be sold.

Disseminated ore - Ore carrying small particles of valuable minerals spread more or less uniformly through the host rock.

Dividend - Cash or stock awarded to preferred and common shareholders at the discretion of the company's board of directors.

Dividend claim - Made when a dividend has been paid to the previous holder because stock has not yet been transferred to the name of the new owner.

Doré bar - The final saleable product of a gold mine. Usually consisting of gold and silver.

Drag fold - The result of the plastic deformation of a rock unit where it has been folded or bent back on itself.

Drawpoint - An underground opening at the bottom of a stope through which broken ore from the stope is extracted.

Drift - A horizontal underground opening that follows along the length of a vein or rock formation as opposed to a crosscut which crosses the rock formation.

Drifter - A hydraulic rock drill used to drill small-diameter boles for blasting or for installing rock bolts.

Drill-indicated reserves - The size and quality of a potential orebody as suggested by widely spaced drill-holes; more work is required before reserves can be classified as probable or proven.

Dry - A building where the miner changes into working clothes.

Due diligence - The degree of care and caution required before making a decision; loosely, a financial and technical investigation to determine whether an investment is sound.

Dump - A pile of broken rock or ore on surface.

Dyke - A long and relatively thin body of igneous rock that, while in the molten state, intruded a fissure in older rocks.