In Prism Resources Inc. v. Detour Gold Corporation,[1] Brown J.A. granted the Appellant’s motion for leave to file a reply factum of five pages. Justice Brown noted that a gap exists in appellate written advocacy, in both the civil and criminal appeal rules, that causes inefficiency and unnecessary costs. Justice Brown recommended that the Rules be amended to permit appellants to file a reply factum of up to five pages.


Detour Gold involves a dispute between Prism, a precious metal explorer and developer, and Detour, an intermediate gold producer and the owner of the lands in issue.[2] Prism brought a summary judgment action motion against Detour; at issue was whether agreements between Prism and Detour created an interest in the land, and whether Detour was otherwise obligated to acknowledge and abide by Prism’s claim to royalty rights in the land.[3] Summary judgment was granted as requested.

Detour, the appellant, brought a motion before the Court of Appeal for Ontario for leave to file a reply factum of five pages. The motion was unopposed.

The Court’s Decision

A. The Current State of the Law

Currently, the respective rules for civil and criminal appeals allow for reply factums in the following circumstances:

(a) Civil appeals: The appellant must bring a motion for leave to file a reply factum (Rules of Civil Procedure, r. 61.16).[4]

(b) Criminal appeals: Where an appeal is in writing, the appellant may file a reply factum up to 10 pages (Criminal Appeal Rules, r. 47(1)). In all other appeals, the appellant must apply for leave to file a reply factum, which a judge may only grant in “exceptional circumstances” (Criminal Appeal Rules, r. 40(8)).[5]

Justice Brown explained that the current culture of the Court of Appeal is for all panel members to be well-briefed on any given appeal before its oral hearing. Except in the most complex of cases, the time for oral submissions is best used addressing the questions posed by the panel members, rather than providing the basics of the appeal.[6] In his view, the absence in both the civil and criminal appeal rules of a right to deliver a short reply factum may prevent the panel on utilizing the oral submissions time in the most effective manner.[7]

B. Amending the Rules will Permit More Cost-Effective Appeals

Justice Brown concluded that amending the civil and criminal appeal rules to allow appellants to file a brief reply factum (which he defined as five pages) in any appeal will rectify the gap that currently exists in the rules and allow the panel to better prepare for oral argument.[8] Not only would amending the rules benefit the Bench, by allowing them to tailor their questions to counsel more appropriately, but it would also save parties unnecessary costs (Justice Brown estimated that this motion would cost the appellant roughly $5,000, for which he apologized for having to impose).[9] It would additionally benefit counsel by allowing them to get to the “meat” of the case during oral submissions, knowing that they had fully put forward their client’s position on key matters in writing.[10]


Detour Gold is a significant decision in recognizing the importance of appellants’ right to written reply in both civil and criminal appeals. Should the rules be amended as recommended by Brown J.A., this will have important implications for counsel appearing before the Court of Appeal. It remains to be seen whether the Rules Committee will follow Brown J.A.’s recommendation and whether similar motions will be granted by other members of the Court in the near future.

Case Information

Prism Resources Inc. v. Detour Gold Corporation, 2022 ONCA 4

Docket: M53057 (C69430)

Date of Decision: January 5, 2022