mining shares, as investors weighed hawkish comments from Federal Reserve Chair Kevin Warsh and doubted that second-quarter strength in Canada’s economy would be sustained. The S&P/TSX Composite Index ended down 280.33 points, or 0.8 percent, at 36,553.92, its lowest closing level since August 20. For the week, the index was down 0.2 percent, adding to its slight decline in the prior week, despite all six major banks reporting stronger-than-expected quarterly earnings. US benchmark the S&P 500 also lost ground, with investors turning cautious after Warsh reiterated the central bank’s focus on fighting inflation. Canadian GDP increased at an annualized rate of 3.3 percent in the second quarter after six months of virtually no growth, aided by strong jump in exports and solid domestic demand, while an advanced indicator showed that the economy was largely flat in July. “The breakdown of second-quarter GDP growth was even better than the solid 3.3…