# Relationship history for MSHA mine 4101901

Current hierarchy: **Amrize South Central → Permian Basin Materials Aggregate → Damron Sand**

- 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:** G R Damron Sand & Gravel Company → Damron Sand; 1950-01-01 to 2014-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Michael  Damron → Damron Sand; 1950-01-01 to 2014-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Damron → G R Damron Sand & Gravel Company; 1950-01-01 to 2014-09-30; source msha-controller-operator-history
- **operator_operates_mine:** PBM Aggregates, LLC → Damron Sand; 2014-10-01 to 2017-06-22; source msha-controller-operator-history
- **controller_controls_mine:** PBM Holdings → Damron Sand; 2014-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** PBM Holdings → PBM Aggregates, LLC; 2014-10-01 to 2017-06-22; source msha-controller-operator-history
- **controller_controls_mine:** W L Ross & Co LLC et al → Damron Sand; 2015-08-01 to 2026-02-17; source msha-controller-operator-history
- **operator_operates_mine:** Permian Basin Materials, LLC → Damron Sand; 2017-06-23 to 2026-02-17; source msha-controller-operator-history
- **controller_controls_operator:** W L Ross & Co LLC et al → Permian Basin Materials, LLC; 2017-06-23 to 2026-02-17; source msha-controller-operator-history
- **controller_controls_mine:** Amrize South Central → Damron Sand; 2026-02-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize South Central → Permian Basin Materials, LLC; 2026-02-18 to 2026-02-17; source msha-controller-operator-history
- **operator_operates_mine:** Permian Basin Materials Aggregate → Damron Sand; 2026-02-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize South Central → Permian Basin Materials Aggregate; 2026-02-18 to current/open; source msha-controller-operator-history