(Adds details, updates prices) Aug 11 (Reuters) - Canada’s main stock index held near record-high levels on Wednesday, as higher gold prices helped the heavyweight mining sector offset losses in energy stocks weighed down by oil market volatility. * At 9:42 a.m. ET (13:42 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 15.92 points, or 0.08%, at 20,511.66. * The materials sector, which includes precious and base metals miners and fertilizer companies, added 1.3%. It was the top boost to the benchmark index as gold prices jumped 1% after slowing U.S. inflation growth saw markets scaling back their expectations for early tapering by the Federal Reserve. * The energy sector dropped 0.6% as oil prices sank after the United States urged the OPEC+ to increase supply. * The financials sector gained 0.2%. The industrials sector rose 0.1%. * On the TSX, 122 issues advanced, while 99 issues declined in a 1.23-to-1 ratio favoring gainers, with 15.16 million shares traded. * The largest percentage gainer on the TSX was ATS Automation Tooling Systems, which jumped 8.4% after its quarterly results beat estimates. * Canada Goose fell 12.3%, the most on the TSX, despite its quarterly results beating expectations, as it could face headwinds from a resurgence in COVID-19 cases. * The most heavily traded shares by volume were Manulife Financial, Bombardier Inc and Enbridge Inc . * The TSX posted 15 new 52-week highs and one new low. * Across Canadian issues, there were 69 new 52-week highs and four new lows, with total volume of 29.74 million shares. Reporting by Ambar Warrick; Editing by Subhranshu Sahu and Vinay Dwivedi Our Standards: The Thomson Reuters Trust Principles.