The Secretary of the Interior is authorized, in order to carry out the purposes mentioned in section 571 of this title, to make financial contributions on the basis of programs or projects approved by the Secretary to the Commonwealth of Pennsylvania (hereinafter designated as the “Commonwealth”) to seal abandoned coal mines and to fill voids in abandoned coal mines, in those instances where such work is in the interest of the public health or safety, and for control and drainage of water which, if not so controlled or drained, will cause the flooding of anthracite coal formations, said contributions to be applied to the cost of drainage works, pumping plants, and related facilities but subject, however, to the following conditions and limitations: