# Relationship history for MSHA mine 4101916

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

- 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:** Porter Sand & Gravel Inc → Grandfalls; 1950-01-01 to 2005-03-31; source msha-controller-operator-history
- **controller_controls_mine:** James R Porter → Grandfalls; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James R Porter → Porter Sand & Gravel Inc; 1950-01-01 to 2005-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Larry  Bates  et al → Grandfalls; 2002-07-11 to 2013-10-01; source msha-controller-operator-history
- **operator_operates_mine:** Crockett County Mining → Grandfalls; 2005-04-01 to 2015-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Larry  Bates  et al → Crockett County Mining; 2005-04-01 to 2013-10-01; source msha-controller-operator-history
- **controller_controls_mine:** W L Ross & Co LLC et al → Grandfalls; 2013-10-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W L Ross & Co LLC et al → Crockett County Mining; 2013-10-02 to 2015-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Permian Basin Materials, LLC → Grandfalls; 2015-08-01 to 2026-02-17; source msha-controller-operator-history
- **controller_controls_mine:** W L Ross & Co LLC et al → Grandfalls; 2015-08-01 to 2026-02-17; source msha-controller-operator-history
- **controller_controls_operator:** W L Ross & Co LLC et al → Permian Basin Materials, LLC; 2015-08-01 to 2026-02-17; source msha-controller-operator-history
- **controller_controls_mine:** Amrize South Central → Grandfalls; 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 → Grandfalls; 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