TORONTO (Reuters) — The Toronto Stock Exchange’s main index finished almost 90 points lower yesterday as mining shares sank and the price of oil declined to below $50, dragging energy issues lower.The S&P/TSX composite index dropped 89.73 points, or 0.7 percent, to close at 12,640.68. The materials group, which includes Canada’s biggest mining names, dropped 1.6 percent, while the energy sector fell 1.1 percent.

Overall, six of the benchmark’s 10 main groups fell, including information technology, which lost 2 percent as Research In Motion Ltd. gave up C$7.53, or 5 percent, to C$142.67. Analysts have raised concerns about the high valuation being placed on RIM shares in recent days.

The S&P/TSX 60 index of bluechip names dropped 6.75 points, or 0.9 percent, to 724.45.

Volume was about 363 million shares worth C$6.2 billion as losers outpaced advancers 885 to 691.

The index’s broad downturn came as oil slipped below $50 a barrel for the first time since May 2005 after data showed a sharp spike in US crude supplies. US crude oil futures settled down $1.76 at $50.48, after falling as low as $49.90 a barrel.

Among Canadian producers, EnCana Corp. shed C$1.29, or 2.4 percent, to C$53.59 and Petro-Canada lost C$1.28, or 2.9 percent, to C$42.40.