(1) Before commencing to drill a well, the operator must construct proper and adequate slush pits according to the plan in the application for permit to drill approved by the board.

(2) If cable tools are used, sufficient casing must be set to protect all fresh water located at levels reasonably accessible for agricultural and domestic use, and, before drilling below the casing point proceeds, such casing must be tested by bailing to ensure a shutoff.

(3) Natural gas that may be encountered in a substantial quantity in any section of a cable-tool-drilled hole above the ultimate objective must be shut off with reasonable diligence and confined to its original source. Any gas escaping from the well during drilling operations must be conducted a safe distance from the well site.

(4) A casing program adopted for cable-tool-drilled wells must be so planned as to protect any potential oil or gasbearing horizons penetrated during drilling from infiltration of injurious waters from other horizons, to prevent the migration of oil or gas from one horizon to another, and to prevent migration of oil, salt water, or other contaminants into freshwater aquifers.

(5) Freshwater-based drilling fluid must be used when drilling the surface hole prior to setting surface casing and when drilling through freshwater aquifers anywhere within the state of Montana.