# Relationship history for MSHA mine 1518162

Current hierarchy: **Gary Wayne  Johnson → Black Hills Coal Inc → Happy Hollow Mine**

- 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

- **controller_controls_mine:** Chester J  Rust → Happy Hollow Mine; 1993-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rust Of Kentucky Inc → Happy Hollow Mine; 1999-04-01 to 1999-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Chester J  Rust → Rust Of Kentucky Inc; 1999-04-01 to 1999-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Gary Wayne  Johnson → Happy Hollow Mine; 1999-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Black Hills Coal Inc → Happy Hollow Mine; 1999-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary Wayne  Johnson → Black Hills Coal Inc; 1999-11-01 to current/open; source msha-controller-operator-history