72 Pa. Stat. § 728
It shall be the duty of the individual, or the superintendent or other officer, in charge of any mine or mines or washery or operation, to assess the tax imposed by law upon the value of anthracite coal prepared for market, from time to time as the coal is mined, washed or screened, and is ready for shipment or market, and to ascertain and assess daily the number of gross tons of coal so mined, washed or screened, and to fix the value thereof. The said individual, superintendent or other officer, in charge of any such mine or mines, washery or screening operation, shall make annually, on or before the first day of February, for the calendar year next preceding, a report in writing to the Department of Revenue, on forms prescribed and furnished by it, stating specifically the number of gross tons of coal made taxable, the assessed value thereof during the calendar year covered by the report, and the amount of tax assessed thereon.
72 P.S. § 728