* WCS for December delivery in Hardisty, Alberta, settled at $28.00 a barrel under WTI, according to CalRock, weakening from $27.85 a barrel under WTI on Friday.
* The discount on heavy Canadian crude has been steadily deepening in recent weeks due to overlapping refinery turnarounds that have reduced oil demand, and concerns the 590,000 barrel-per-day Trans Mountain pipeline expansion will be delayed beyond the first quarter of 2024.
* Benchmark oil prices edged higher after top exporters Saudi Arabia and Russia reaffirmed their commitment to extra voluntary oil supply cuts until the end of the year.
* The outright price of WCS was just under $53 a barrel.
(Reporting by Nia Williams in British Columbia; Editing by Krishna Chandra Eluri)