# Relationship history for MSHA mine 1515860

Current hierarchy: **Keener Clifford B → 32 Mining Inc → #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:** Davis Don B → #1; 1986-01-31 to 1987-03-25; source msha-controller-operator-history
- **operator_operates_mine:** Martin Holding Company Inc → #1; 1986-12-01 to 1987-03-25; source msha-controller-operator-history
- **controller_controls_operator:** Davis Don B → Martin Holding Company Inc; 1986-12-01 to 1987-03-25; source msha-controller-operator-history
- **operator_operates_mine:** 32 Mining Inc → #1; 1987-03-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Keener Clifford B → #1; 1987-03-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keener Clifford B → 32 Mining Inc; 1987-03-26 to current/open; source msha-controller-operator-history