# Relationship history for MSHA mine 1518831

Current hierarchy: **J Mark  Campbell → Clintwood Elkhorn Mining Co. → Island Creek Surface Mine #1**

- 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:** TECO Energy Inc → Island Creek Surface Mine #1; 1988-04-26 to 2015-09-20; source msha-controller-operator-history
- **operator_operates_mine:** Clintwood Elkhorn Mining Co. → Island Creek Surface Mine #1; 2005-01-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** TECO Energy Inc → Clintwood Elkhorn Mining Co.; 2005-01-04 to 2015-09-20; source msha-controller-operator-history
- **controller_controls_mine:** James H  Booth et al → Island Creek Surface Mine #1; 2015-09-21 to 2019-06-15; source msha-controller-operator-history
- **controller_controls_operator:** James H  Booth et al → Clintwood Elkhorn Mining Co.; 2015-09-21 to 2019-06-15; source msha-controller-operator-history
- **controller_controls_mine:** J Mark  Campbell → Island Creek Surface Mine #1; 2019-06-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** J Mark  Campbell → Clintwood Elkhorn Mining Co.; 2019-06-16 to current/open; source msha-controller-operator-history