(Updates prices, sectors) July 30 (Reuters) - Canada’s main stock index fell on Friday, weighed by weakness in energy and mining stocks, while official data showed the nation’s economy most likely expanded in June. * The energy sector dropped 0.8% on weaker crude prices, while the materials sector, which includes precious and base metals miners and fertilizer companies, lost 0.3% as gold futures fell 0.3% to $1,825 an ounce. * At 9:35 a.m. ET (1335 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 54.11 points, or 0.27%, at 20,257.67. * Statistics Canada said the Canadian economy most likely expanded by 0.7% in June as businesses reopened after shutdowns imposed to help fight the coronavirus pandemic. * While producer prices in Canada were unchanged in June from May as a decline in lumber prices offset rises in other categories, Statistics Canada said. * Eldorado Gold Corp fell 4.5%, the most on the TSX, after the miner missed its second-quarter revenue estimates, and the second biggest decliner was lithium miner Lithium Americas Corp, down 2.2%. * The financials sector slipped 0.2%. The industrials sector remain unchanged. * On the TSX, 83 issues were higher, while 137 issues declined for a 1.65-to-1 ratio to the downside, with 9.08 million shares traded. * The largest percentage gainers on the TSX were Restaurant Brands International Inc, which jumped 3.9% after the restaurant chain posted an upbeat second-quarter results and construction company SNC-Lavalin Group Inc , which rose 2.9% after reporting its second-quarter earnings. * The most heavily traded shares by volume were Bank of Montreal, Canadian Utilities Ltd, and Emera Inc . * The TSX posted no new 52-week highs and no new lows. * Across all Canadian issues there were 17 new 52-week highs and three new lows, with total volume of 16.95 million shares. (Reporting by Amal S in Bengaluru) Our Standards: The Thomson Reuters Trust Principles.