# Relationship history for MSHA mine 4104140

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Southwest, Inc → Cobey**

- 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:** Alma  Tausch → Cobey; 1990-02-01 to 2009-10-29; source msha-controller-operator-history
- **operator_operates_mine:** Medina Crushed Stone Inc. → Cobey; 2000-02-01 to 2011-06-17; source msha-controller-operator-history
- **controller_controls_operator:** Alma  Tausch → Medina Crushed Stone Inc.; 2000-02-01 to 2009-10-29; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Cobey; 2007-11-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Vernon  Tausch  et al → Cobey; 2009-10-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vernon  Tausch  et al → Medina Crushed Stone Inc.; 2009-10-30 to 2011-06-17; source msha-controller-operator-history
- **controller_controls_operator:** Zachary  Tausch  et al → Medina Crushed Stone Inc.; 2009-10-30 to 2011-06-17; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Southwest, Inc → Cobey; 2011-06-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Southwest, Inc; 2011-06-18 to current/open; source msha-controller-operator-history