The following terms are applicable when used in the chapter and shall be defined as follows unless the context clearly requires otherwise:

(1) "Abandon" means the removal of all drilling and production equipment from the site and the restoration of the surface of the site to standards set forth by the Office of Surface Mining in 30 C.F.R., Part 947, "Surface Mining and Reclamation Operation Under a Federal Program for the State of Washington" or a federally approved state program.

(2) "Auction" means competitive lease bidding by oral or sealed bids or a combination thereof.

(3) "Blending" means combining two or more grades of coal to achieve desired chemical or combustive properties.

(4) "Coal" means a black or brownish-black solid combustible substance which has been subjected to the natural process of coalification and which falls within the classification of coal by rank for lignite, subbituminous, bituminous or anthracite as defined in the American Society of Testing Material Standards.

(5) "Coal mining lease" means a lease not to exceed twenty years entitling the operator to develop, mine and market a known coal resource on state lands.

(6) "Coal option contract" means a one-year agreement entitling its holder to explore for coal on one section or 640 acres, whichever is larger and to remove up to 250 tons of coal for testing purposes.

(7) "Commingling" means the mixing of coal from the leased premises with coal from land other than the leased premises.

(8) "Department" means the department of natural resources.

(9) "Development" means any work which occurs after exploration and which furthers coal production.

(10) "Exploration" means investigation to determine presence, quantity and quality of coal resources by geologic, geophysical, geochemical or other means.

(11) "Exploration drill hole" means an exploratory drill hole constructed for the purpose of determining depth, thickness, quality and quantity of coal for the identification of underlying rock formations in which the coals occur and the determination of hydrological conditions.

(12) "Gross receipts from mining" means the fair market price per ton according to rank as prepared for market at the first point of sale or commercial use.

(13) "Grout" means a cementing agent which is used for plugging and sealing exploration drill holes.

(14) "Improvements, structures, and development work" means anything considered a fixture in law or the removal of overburden or the diversion of drainage or other work preparatory to removal of coal, placed upon or attached to state lands that has added value to the state's interest therein.

(15) "Logical mining unit" means contiguous lands or lands in reasonable proximity in which the recoverable coal reserves can be developed in an efficient, economical, and orderly manner as a unit with due regard to recoverable coal reserves. A logical mining unit may consist of one or more state leases under the control of a single lessee and may include intervening or adjacent lands in private or public ownership.

(16) "Mine" means any excavation made for production of coal for commercial sale or use.

(17) "Office of surface mining" means United States Department of the Interior, Office of Surface Mining Reclamation and Enforcement or its successor.

(18) "Plug and abandon" means the placing of permanent plugs in a coal exploration drill-hole in such a way and at such intervals as are necessary to prevent future leakage of either fluid or gases from the drill hole to the surface or from one aquifer to another.

(19) "Production" means the work of extracting and preparing coal in commercial quantities for market or for consumption.

(20) "Reclamation" means rehabilitation of surface-mined areas to those required standards set forth by the Office of Surface Mining in 30 C.F.R., Part 947, "Surface Mining and Reclamation Operation Under a Federal Program for the State of Washington" or by a federally approved state program.

(21) "SEPA" means the State Environmental Policy Act, chapter 43.21C RCW.

(22) "State land" means land where all or part of the subsurface coal rights are owned by the state and are managed by the department.

(23) "Surface rights" means the rights to the use of the surface of the property not including subsurface rights.

(24) "Ton" means ton as defined by RCW 79.01.668.

(25) "Treatment" means improving the physical or chemical properties of coal.

(26) "Washing" means the separation of coal from undesired contaminants through use of a fluid medium.