# Relationship history for MSHA mine 2302232

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Kansas City, LLC → Stamper Underground**

- 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:** Hunt Midwest Enterprises → Stamper Underground; 1985-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hunt Midwest Mining Inc → Stamper Underground; 2001-04-01 to 2005-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Hunt Midwest Enterprises → Hunt Midwest Mining Inc; 2001-04-01 to 2005-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Kansas City, LLC → Stamper Underground; 2005-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc et al → Stamper Underground; 2005-02-01 to 2014-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc et al → Martin Marietta Kansas City, LLC; 2005-02-01 to 2014-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Hunt Midwest Enterprises et al → Martin Marietta Kansas City, LLC; 2005-02-01 to 2014-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Stamper Underground; 2014-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Kansas City, LLC; 2014-04-03 to current/open; source msha-controller-operator-history