# Relationship history for MSHA mine 4607956

Current hierarchy: **Mikel Edward → Houck & Company Inc → Independence 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:** Houck & Company Inc → Independence Mine; 1990-10-01 to 1991-11-20; source msha-controller-operator-history
- **controller_controls_mine:** Houck Dan → Independence Mine; 1990-10-01 to 1991-11-20; source msha-controller-operator-history
- **controller_controls_operator:** Houck Dan → Houck & Company Inc; 1990-10-01 to 1991-11-20; source msha-controller-operator-history
- **operator_operates_mine:** Houck & Company Inc → Independence Mine; 1991-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mikel Edward → Independence Mine; 1991-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mikel Edward → Houck & Company Inc; 1991-11-21 to current/open; source msha-controller-operator-history