Descendants of East County coal and sand miners of yesteryear cut the ribbon Saturday on the newly built Greathouse Portal and re-opened Visitor Center at Black Diamond Mines Regional Preserve. Joining the ribbon cutters, far left, is Supervising Naturalist Traci Parent, whose recently published “Rose Hill: A Comprehensive History of a Pioneer Cemetery” explores the fascinating history of the people who lived – and died – in the hills south of Antioch. According to Mine Supervisor John McKana, the current 800-foot mine tour, when its expansion is completed, will cover 1,150 feet and become the only underground portal-to-portal mining museum in California.