It shall be the duty of every producer to keep a record of all sales, deliveries and shipments of anthracite, showing the name of the person to whom sold or delivered, the date thereof, the size and net weight, the point of delivery, the railroad car number, the model and registration of the vehicle in which the anthracite was transported, and whether the anthracite so sold, delivered or shipped was sold, delivered or shipped as standard anthracite or substandard anthracite.

It shall be the duty of every wholesale dealer, retail dealer, of every person engaged in hauling anthracite from a railroad car direct to a consumer, and municipal weighmaster, to keep and retain all statements issued to or retained by him, in accordance with the provisions of this act. It shall also be the duty of every retail dealer and every person engaged in hauling anthracite from a railroad car direct to a consumer and every municipal weighmaster to keep a duplicate of the weighmaster's certificate, and of every wholesale dealer, of the invoice issued by him, in accordance with the provisions of section four¹ of this act.

All such records shall be written and preserved for a period of two years and shall be open to inspection by the department acting through its mine inspectors during regular business hours.