25 CFR § 585.5 - How do I file a motion to intervene?
(a) An entity or individual, whether acting on his or her own behalf or as an agent of another entity, not permitted to appeal, may be permitted to participate as a party to a pending appeal if the Commission finds that:
(1) The final decision could directly and adversely affect it or the class it represents;
(2) The individual or entity may contribute materially to the disposition of the proceedings;
(3) The individual's or entity's interest is not adequately represented by existing parties; and
(4) Intervention would not unfairly prejudice existing parties or delay resolution of the proceeding.
(b) A tribe with jurisdiction over the lands on which there is a gaming operation that is the subject of a proceeding under this part may intervene as a matter of right if the tribe is not already a party.
(c) A motion to intervene shall be submitted to the Commission within 10 days of the notice of appeal. The motion shall be filed with the Commission and served on each person who has been made a party at the time of filing. The motion shall succinctly state:
(1) The moving party's interest in the proceeding;
(2) How his or her participation as a party will contribute materially to the disposition of the proceeding;
(3) Who will appear for the moving party;
(4) The issues on which the moving party seeks to participate; and
(5) Whether the moving party seeks to present witness affidavits.
(d) Objections to the motion must be filed by any party within 10 days after service of the motion.
(e) A reply brief to the brief in opposition may be filed within 5 days of service of the brief in opposition.
(f) When motions to intervene are made by individuals or groups with common interests, the Commission may request all such movants to designate a single representative, or the Commission may recognize one or more movants.
(g) The Commission shall give each movant and party written notice of the decision on the motion. For each motion granted, the Commission shall provide a brief statement of the reason(s) for the decision. If the motion is denied, the Commission shall briefly state the ground(s) for denial. The Commission may allow the movant to participate as amicus curiae, if appropriate.