Modern milling techniques, sophisticated prospecting methods, and fertile ground for prospects - the location of one of the world's greatest gold discoveries - all point to the idea that there could be profitable gold mining in California. California environmental laws combined with a large urban population in much of the old California Gold Country are enough to mean that gold mining there in the near future is not likely. The industry generally regards the state environmental laws and large residential populations in the area as too much of an obstacle to oppose. There are exceptions, and there are efforts to revive gold mining. See this article for example.