# Relationship history for MSHA mine 1518535

Current hierarchy: **J Mark  Campbell → Premier Elkhorn Coal Co. → Job #39**

- 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:** TECO Energy Inc → Job #39; 1991-12-02 to 2015-09-20; source msha-controller-operator-history
- **operator_operates_mine:** Premier Elkhorn Coal Co. → Job #39; 2002-04-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** TECO Energy Inc → Premier Elkhorn Coal Co.; 2002-04-10 to 2015-09-20; source msha-controller-operator-history
- **controller_controls_mine:** James H  Booth et al → Job #39; 2015-09-21 to 2019-06-15; source msha-controller-operator-history
- **controller_controls_operator:** James H  Booth et al → Premier Elkhorn Coal Co.; 2015-09-21 to 2019-06-15; source msha-controller-operator-history
- **controller_controls_mine:** J Mark  Campbell → Job #39; 2019-06-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** J Mark  Campbell → Premier Elkhorn Coal Co.; 2019-06-16 to current/open; source msha-controller-operator-history