Main.java

public class Main extends JavaPlugin {
	
	private static Main instance;
	
	public void onEnable(){
		instance = this;
	}
	
	public void onDisable(){
		Manager.miners = null;
	}
	
	public static Main getInstance() {
    		return instance;
    	}
	
}

Manager.java

public class Manager {

	public static HashMap<Location, String> miners = new HashMap<Location, String>();
	
	public static void registerTool(Block b){
		miners.put(b.getLocation(), WorldGuard.getRegionName(b.getLocation()));
	}
	
}

Miner.java

public class Miner {
	
		public Miner() {
			new BukkitRunnable() {
				public void run() {
					Manager.miners.values().removeIf(s -> Collections.frequency(Manager.miners.values(), s) > 10);
					Manager.miners.keySet().stream().collect(Collectors.toList()).forEach(l -> run(l));
				}
			}.runTaskTimer(Main.getInstance(), 60L, 60L);
		}
		
		public void run(Location loc) {
			//Do stuff
		}
		
}