All papers, records, and documents of the department, and applications for permits pending before the department, shall be public records open to inspection during business hours: Provided, however, That information which pertains only to the analysis of the chemical and physical properties of the coal (excepting information regarding such mineral or elemental content which is potentially toxic in the environment) shall be kept confidential and not made a matter of public record. Copies of all such public records and the rules and regulations of the department shall be received in evidence in all courts and elsewhere, subject to the rules of law concerning evidence.