Coles has demanded evidence used to support claims it could force the closure of a competitor by opening a second supermarket in a regional city. The competition watchdog used new powers on July 1 to block Coles from developing a new supermarket at Kalgoorlie in Western Australia. The outback city's 30,000 residents are currently served by four supermarkets: a Coles, a Woolworths and two independents. The ACCC blocked the second Coles supermarket based on theories of harm, the court was told. It's not the first time the watchdog has knocked back a supermarket acquisition.