# Relationship history for MSHA mine 3606997

Current hierarchy: **Kroh John → Sulfur Creek Coal Company → Big Vein 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

- **operator_operates_mine:** Sulfur Creek Coal Company → Big Vein Slope; 1980-07-01 to 1982-06-10; source msha-controller-operator-history
- **controller_controls_mine:** Poletti Peter & James Shade Et Al → Big Vein Slope; 1980-07-01 to 1982-06-10; source msha-controller-operator-history
- **controller_controls_operator:** Poletti Peter & James Shade Et Al → Sulfur Creek Coal Company; 1980-07-01 to 1982-06-10; source msha-controller-operator-history
- **operator_operates_mine:** Sulfur Creek Coal Company → Big Vein Slope; 1982-06-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kroh John Et Al → Big Vein Slope; 1982-06-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kroh John Et Al → Sulfur Creek Coal Company; 1982-06-11 to current/open; source msha-controller-operator-history