(Adds details throughout, updates prices)
TORONTO, April 18 (Reuters) - Canada's main stock index rose for the fifth straight day on Wednesday to reach a four-week high, as energy and metal mining companies led broad-based gains, boosted by higher commodity prices.
* The Toronto Stock Exchange's S&P/TSX composite index closed up 176.67 points, or 1.15 percent, at 15,529.97.
* The energy group surged 3.6 percent, as oil prices climbed after sources signaled top exporter Saudi Arabia wanted to see prices closer to $100 a barrel.
* Shares of Suncor Energy rose 2.3 percent and oil and gas producer Canadian Natural Resources was up 3.3 percent.
* U.S. crude prices settled 2.9 percent higher at $68.47 a barrel.
* The government of British Columbia said it would file a legal challenge to Kinder Morgan Canada Ltd's Trans Mountain pipeline expansion by month-end, even as an opinion poll showed mounting public support for the project.
* Still, shares of Kinder Morgan Canada rose 2.8 percent. After the close, the company reported a 5.1 percent drop in first-quarter profit, hurt by a fall in volumes of crude oil and refined products transports.
* The materials group, which includes precious and base metals miners and fertilizer companies, added 1.9 percent.
* Copper prices advanced 2.3 percent to $7,036.5 a tonne.
* Gains for the TSX came as the Bank of Canada signaled more interest rate hikes would be coming after it held its benchmark rate steady at 1.25 percent, but said it did not know when or how aggressive it would need to be to keep inflation in check.
* All of the TSX's 10 main groups climbed. That included a 0.5 percent gain for financials, while industrials were up 1.2 percent.
* The largest percentage gainer on the TSX was Torc Oil & Gas, which rose 9.9 percent, while the largest decliner was Alaris Royalty, down 6.7 percent.
* Among the most active Canadian stocks by volume were Bombardier Inc, up 4.0 percent to $3.92, Athabasca Oil Co, up 9.1 percent to $1.56 and Aurora Cannabis , up 2.3 percent to $8.63.
* The index posted 19 new 52-week highs and two new lows. (Reporting by Fergal Smith; Editing by Peter Cooney)