# Relationship history for MSHA mine 0404302

Current hierarchy: **Don Williams Mining Company → Don Williams Mining Company → Keystone Placer**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Don Williams Mining Company → Keystone Placer; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Don Williams Mining Company → Keystone Placer; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don Williams Mining Company → Don Williams Mining Company; 1979-01-01 to current/open; source msha-controller-operator-history