Mining Act Article 9

The horizontal surface area of a mineral concession shall be from a minimum of two hectares to a maximum of two hundred and fifty hectares; however, in the need for development, the maximum area of the mineral concession may be extended to three hundred hectares if it is deemed necessary after the competent authority invites local governments, experts and scholars to jointly investigate.The area of the petroleum and natural gas concession may not be subject to the restriction on the maximum area under the preceding Paragraph, with approval by the competent authority based on the geological structure of oil and gas reserves.
中文原文 礦業法第9條
礦區之地面水平面積,以二公頃至二百五十公頃為限。
但因礦牀之合理開發需要,經主管機關邀集地方政府、專家及學者共同勘查,認為必要時,得增加至三百公頃。
石油礦及天然氣礦礦區面積,得依儲油氣地質構造,由主管機關核定,不受前項最大面積之限制。

English translation for reference only; the Chinese text prevails. Not legal advice.