Section 81
SEC. 81. Any person, association, or corporation holding a lease under the provisions of this Act shall perform during each year, while the lease is in force, not less than two hundred pesos worth of labor, or of improvements, on each mining claim of the first and fifth group, and one hundred pesos worth of labor, or of improvements on each claim of the second and fourth group: Provided, That in the case of a lease covering a group of two or more mining claims leased or held in common, the total amount of labor or improvements required for the said group may be concentrated on any one of the said group, either on the surface or under the ground. The period within which the work required to be done annually on all mining claims shall commence on the first day of January succeeding the date of the granting of the lease on the said claim or claims, and shall be completed on or before the thirty-first day of December of the same year: Provided, further, That failure to perform the annual labor or improvements required herein shall constitute abandonment on the part of the holder and the land shall be subject to relocation by other persons.