# Relationship history for MSHA mine 1513637

Current hierarchy: **Ashland Inc → Arch On The Green Inc → Nelson Creek 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

- **controller_controls_mine:** Natomas Company → Nelson Creek Mine; 1978-04-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Brown Badgett Inc → Nelson Creek Mine; 1982-08-01 to 1987-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Natomas Company → Brown Badgett Inc; 1982-08-01 to 1987-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Arch On The Green Inc → Nelson Creek Mine; 1987-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → Nelson Creek Mine; 1987-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Arch On The Green Inc; 1987-06-01 to current/open; source msha-controller-operator-history