Tips to reduce the difficulty and to maximize the profit as high as possible: 1. Always maximize the digging capacity as low as possible. This helps you dig for a much better kind of ore to sell and helps you earn money spontaneously. 2. Upgrade cooling and capacity as high as possible. Helps dig lower and store more ore for more profit. 3. Dare to take risks. As soon as you dig low enough, use up to 20% left of your energy. Then go back to repair. 4. Repeat. Good luck!