# Relationship history for MSHA mine 3606730

Current hierarchy: **Clark Robert C → Clark Coal Company → No 1 Slope**

- 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:** Grego Stanley F Et Al → No 1 Slope; 1976-03-25 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B G P T Coal Company → No 1 Slope; 1978-09-01 to 1980-09-29; source msha-controller-operator-history
- **controller_controls_operator:** Grego Stanley F Et Al → B G P T Coal Company; 1978-09-01 to 1980-09-29; source msha-controller-operator-history
- **operator_operates_mine:** Clark Coal Company → No 1 Slope; 1980-09-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Clark Robert C → No 1 Slope; 1980-09-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Clark Robert C → Clark Coal Company; 1980-09-30 to current/open; source msha-controller-operator-history