(a) Only those individuals who are eligible under the provisions of this section may practice before the Department, but this provision shall not be deemed to restrict the dealings of Indian tribes or members of Indian tribes with the Department.

(b) Unless disqualified under the provisions of § 1.4 or by disciplinary action taken pursuant to § 1.6:

(1) Any individual who has been formally admitted to practice before the Department under any prior regulations and who is in good standing on December 31, 1963, shall be permitted to practice before the Department.

(2) Attorneys at law who are admitted to practice before the courts of any State, the District of Columbia, the Commonwealth of Puerto Rico, American Samoa, the Trust Territory of the Pacific Islands, or the District Court of the Virgin Islands will be permitted to practice without filing an application for such privilege.

(3) An individual who is not otherwise entitled to practice before the Department may practice in connection with a particular matter on his own behalf or on behalf of

(i) A member of his family;

(ii) A partnership of which he is a member;

(iii) A corporation, business trust, or an association, if such individual is an officer or full-time employee;

(iv) A receivership, decedent's estate, or a trust or estate of which he is the receiver, administrator, or other similar fiduciary;

(v) The lessee of a mineral lease that is subject to an operating agreement or sublease which has been approved by the Department and which grants to such individual a power of attorney;

(vi) A Federal, State, county, district, territorial, or local government or agency thereof, or a government corporation, or a district or advisory board established pursuant to statute; or

(vii) An association or class of individuals who have no specific interest that will be directly affected by the disposition of the particular matter.