Canada's main stock index declined slightly on Monday, closing at 13,472.22 points, as bullion prices dropped further after Iran and world powers arrived at an agreement on its nuclear program over the weekend. The S&P/TSX composite index of the Toronto Stock Exchange dipped 6.12 points, or 0.05 percent to conclude at 13,472.22 points, with energy and mining sectors leading the fall. World powers reached an agreement that allowed Iran to keep the central elements of its uranium program while asking it to stop its enrichment at a level lower than what is needed for nuclear weapons. Bullion prices further declined after this agreement over the weekend, which exerted pressure on the energy and mining sectors of the Canadian stock index. The metal and mining sector slid to 756.56 points by 1.11 percent, and the energy shares also stumbled by 0.91 percent to 269.85 points, with Canadian Natural Resources Ltd. losing 0.9 percent to 34.52 Canadian dollars (32.79 U.S. dollars) and Encana Corp., the oil and gas giant, down three cents, or 0.15 percent, at 20.15 Canadian dollars. By contrast, shares of industrials and telecom gained 0.46 percent and 0.45 percent individually on Monday, with Canadian Pacific Railway Ltd. gaining 1.3 percent to 161.11 Canadian dollars. The gold sector suffered great losses from Iran's deal, with Detour Gold Corporation down 11.71 percent to 3.77 Canadian dollars per share. In company news, BlackBerry said two top executives were departing and a third was replaced in a widely expected shakeup following this month's naming of a new chief executive. The stock gained 1.38 percent to 6.60 Canadian dollars apiece. Saputo, Canada's biggest dairy processor, was up six cents, or 0.12 percent, at 48.60 Canadian dollars. The company increased its bid for Australia's oldest dairy processor, offering 9.20 Australian dollars (8.46 U.S dollars) per share if it acquires a majority of Warrnambool Cheese and Butter shares. The new bid added 20 cents per share to its earlier unconditional offer and tops two rival Australian bidders. Canada dollar touches 4-month low following the Iran deal, ending the North American session at 1.0537 Canadian dollars versus the U.S. dollar, weaker than Friday's close of 1.0511 Canadian dollars.