# Relationship history for MSHA mine 2003609

Current hierarchy: **David  Ledsworth; John  Adair; Michael Lee  Humphries → American Rock Products, Inc. → Chrystal Lake**

- 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

- **operator_operates_mine:** American Rock Products, Inc. → Chrystal Lake; 2020-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Adair et al → Chrystal Lake; 2020-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Adair et al → American Rock Products, Inc.; 2020-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Ledsworth et al → American Rock Products, Inc.; 2020-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael Lee  Humphries et al → American Rock Products, Inc.; 2020-08-26 to current/open; source msha-controller-operator-history