private void addMines(double x, double y) {
		for(int i = 0; i < 75; i++) {
			double tx = x + random.nextGaussian() * 6;
			double ty = y + random.nextGaussian() * 6;
			
			StoneMine sm = new StoneMine(tx,ty);
			
			if(isEmpty(sm)) {
				entities.add(sm);
			} else {
				sm = null;
			}
		}
		
		for(int i = 0; i < 200; i++) {
			double tx = x + random.nextGaussian() * 6;
			double ty = y + random.nextGaussian() * 6;
			
			GoldMine sm = new GoldMine(tx,ty);
			
			if(isEmpty(sm)) {
				entities.add(sm);
			} else {
				sm = null;
			}
		}
	}