SINGAPORE, Nov 28 (Reuters Breakingviews) - President Xi Jinping is trying to wean China off its property-based, debt-fuelled economic model. The transformation will cool growth in the world’s second-largest economy after years of rapid development. Investors are worried but risk ignoring the structural changes underpinning the country's continuing voracious appetite for raw materials. Reuters Graphics Take the $300 billion copper market. China imports over 60% of the metal’s globally traded volume. "When it comes to copper, the thinking usually goes that copper equals property, property equals China," said one commodities trader. "And because China property is down, copper must be...