Native gold is the most important placer mineral, but platinum and tin are also found in gravels.
Minerals also include zircon, diamond, ruby, and other gems. This guide focuses on small mining operations represented as sole proprietorships on Schedule C, but it can be adapted for partnership and corporate returns. This text is supplemental to the Audit Technique Guide previously published and which contains in-depth discussions of issues associated with the mining industry. Mining has historically been a cash-based activity. Often the miner will have little, if any, documentation to support the activity.