TORONTO - Some of the most active companies traded Monday on the Toronto Stock Exchange and the TSX Venture Exchange:

Toronto Stock Exchange (12,090.68 up 25.13 points):

Eastern Platinum Ltd. (TSX:ELR). Miner. Down 2.5 cents, or 22.73 per cent, at 8.5 cents on 57.9 million shares.

Colossus Minerals Inc. (TSX:CSI). Miner. Up 39 cents, or 21.79 per cent, at $2.18 on 7.6 million shares.

Osisko Mining Corp. (TSX;OSK). Miner. Up 25 cents, or 6.79 per cent, at $3.93 on 6.4 million shares.

Air Canada (TSX:AC.B). Airline. Down 38 cents, or 12.67 per cent, at $2.62 on 5.5 million shares. The dramatic recovery of the company's shares took a step back Monday after the carrier warned of disappointing first-quarter results that may signal a softening in the airline industry.

Barrick Gold Corp. (TSX: ABX). Miner. Down 16 cents, or 0.86 per cent, at $18.49 on 4.1 million shares.

Orbite Aluminae Inc. (TSX:ORT). Miner. Down 12 cents, or 11.11 per cent, at 96 cents on 4.1 million shares.

Toronto Venture Exchange (944.35 up 5.28 points):

International PBX Ventures Ltd. (TSXV:PBX). Miner. Unchanged at 3.5 cents on 5.1 million shares.

Manas Petroleum Corp. (TSXV:MNP). Oil and gas. Up one cent, or 20 per cent, at six cents on 3.5 million shares.

Companies reporting major news:

Bioniche Life Sciences Inc. (TSX:BNC). Drug developer. Up two cents, or 7.41 per cent, at 29 cents on 402,047 shares. The company says it has been reviewing strategic options for several months, including two overtures from a dissident group of shareholders that publicly chided the company in an open letter released Monday. Their letter, dated April 19, cautioned the directors of the Belleville, Ont.,-based company against attempting to entrench its current board or management which, they said, have a "dismal record" that has resulted in a steep drop in stock value.

Canadian National Railway (TSX:CNR). Down 84 cents, or 0.85 per cent, at $97.64 on 1.03 million shares. The company reported slightly better than expected results for the first quarter despite harsh winter weather. The country's largest railway said Monday it earned $555 million or $1.30 per share for the quarter ended March 31. The results compared with a profit of $775 million or $1.75 per share a year ago, when the company gained $252 million from the sale of rail lines in the Toronto area to Metrolinx.

Rogers Communications Inc. (TSX:RCI.B). Communications and media. Up 32 cents, or 0.62 per cent, at $52.08 on 1.03 million shares. The company reported after markets closed that its first-quarter profits grew 15 per cent, helped partly by more subscribers upgrading their smartphones. Net income rose to $414 million from $360 million.

News from © The Canadian Press, 2013