premise: Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled , That the Secretary of the Interior is hereby authorized and directed to establish and maintain a program of stabilization payments to small domestic producers of lead and <mask> ores and concentrates in order to stabilize the mining of lead and <mask> by small domestic producers on public , Indian , and other lands as provided in this Act .
hypothesis: the proper context for <mask> here should be a bluish-white lustrous metallic element; brittle at ordinary temperatures but malleable when heated; used in a wide variety of alloys and in galvanizing iron; it occurs naturally as zinc sulphide in zinc blende