# Relationship history for MSHA mine 1515497

Current hierarchy: **William K  Ison; Charles K  Ison → Ison Coal Company Inc → Bull Creek Strip**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Charles K  Ison et al → Bull Creek Strip; 1982-05-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Paul J  Sturgill → Bull Creek Strip; 1983-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big Elk Creek Coal Company Inc → Bull Creek Strip; 1986-01-01 to 1987-09-24; source msha-controller-operator-history
- **controller_controls_operator:** Paul J  Sturgill → Big Elk Creek Coal Company Inc; 1986-01-01 to 1987-09-24; source msha-controller-operator-history
- **operator_operates_mine:** Ison Coal Company Inc → Bull Creek Strip; 1987-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charles K  Ison et al → Ison Coal Company Inc; 1987-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William K  Ison et al → Ison Coal Company Inc; 1987-09-25 to current/open; source msha-controller-operator-history