July 25 (Reuters) - Canada's main stock index fell on Thursday after three straight days of gains, hurt by a clutch of downbeat corporate earnings reports.
* Miner Teck Resources Ltd reported a quarterly profit slightly below analysts' estimates, hurt by lower copper and zinc prices. Shares of the company fell 0.5%.
* Oil and gas producer Cenovus Energy fell 2.3% after the company missed quarterly profit estimates as the production cuts ordered by Alberta's provincial government in Canada hit output and higher Canadian crude prices hurt refining margins.
* At 9:40 a.m. ET (1340 GMT), the Toronto Stock Exchange's S&P/TSX Composite index was down 48.11 points, or 0.29%, at 16,563.73.
* All of the index's 11 major sectors were lower, led by the energy sector's 1% drop, hurt by Cenovus.
* The materials sector, which includes precious metal miners, lost 0.8%, hurt by an 8.8% fall in shares of OceanaGold Corp after the miner reported quarterly results.
* OceanaGold fell the most on the TSX, followed by shares of Celestica Inc, which dropped 6.8%.
* Among other reports, Husky Energy Inc posted a better-than-expected quarterly profit, as higher Canadian crude prices following the Alberta government's mandatory output cuts more than offset the company's lower production and weak refining margins.
* The financials sector and the industrials sector each slipped 0.1%.
* On the TSX, 56 issues were higher, while 171 issues declined for a 3.05-to-1 ratio to the downside, with 13.85 million shares traded.
* The largest percentage gainers on the TSX were shares of Mullen Group Ltd, which jumped 6.6% followed by shares of Precision Drilling, which rose 4%.
* The most heavily traded shares by volume were Lundin Mining and OceanaGold.
* The TSX posted six new 52-week highs and two new lows.
* Across all Canadian issues, there were 25 new 52-week highs and nine new lows, with total volume of 23.51 million shares. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Maju Samuel)