# Relationship history for MSHA mine 3609131

Current hierarchy: **David S  Herrholtz → Ligonier Construction Co. → Burns Mine**

- 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:** Sherpa Mining Contractors, Inc. → Burns Mine; 2003-02-10 to 2022-09-01; source msha-controller-operator-history
- **controller_controls_mine:** Andrew J  Hewitson → Burns Mine; 2003-02-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Andrew J  Hewitson → Sherpa Mining Contractors, Inc.; 2003-02-10 to 2022-09-01; source msha-controller-operator-history
- **operator_operates_mine:** Ligonier Construction Co. → Burns Mine; 2022-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David S  Herrholtz → Burns Mine; 2022-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David S  Herrholtz → Ligonier Construction Co.; 2022-09-02 to current/open; source msha-controller-operator-history