25 Pa. Code § 77.192
The following words and terms, when used in this subchapter, have the following meanings, unless the context clearly indicates otherwise:
Cash-The term includes, when used in regard to bond requirements, negotiable certificates of deposit.
Collateral bond-A penal bond agreement in a sum certain, payable to the Department, executed by the operator, and which is supported by the deposit with the Department of cash, negotiable bonds of the United States, the Commonwealth, the Turnpike Commission, the General State Authority, the State Public School Building Authority, or a Commonwealth municipality, or Pennsylvania bank or banking institution, automatically renewable and assignable certificates of deposit or irrevocable and stand-by Commonwealth bank or banking institution letters of credit.
Long term facility-A processing plant located within the permit area, mine drainage facility, refuse area or other structure and facility associated with surface or underground mining which will be an active mine operation for at least 10 years.
Long term mine-An underground mine which will be in active operation for at least 10 years, or a surface mine in which the mineral to be removed exceeds the amount of overburden by a ratio of at least 4:1 and which will be in active operation for at least 10 years.
Surety bond-A penal bond agreement in a sum certain payable to the Department, executed by the operator and a corporation licensed to do business as a surety in this Commonwealth and approved by the Department, and which is supported by the guarantee of payment on the bond by the surety.
25 Pa. Code § 77.192