# Relationship history for MSHA mine 1508243

Current hierarchy: **Ashland Inc → Mac Dougald Construction Company Inc → Surface Mine No 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Ashland Inc et al → Surface Mine No 1; 1975-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mac Dougald Construction Company Inc → Surface Mine No 1; 1975-04-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Mac Dougald Construction Company Inc; 1975-04-10 to current/open; source msha-controller-operator-history