# Relationship history for MSHA mine 1800303

Current hierarchy: **Chaney Enterprises LP → Sustainable Land Use, LLC → Mardela Springs-MD SG**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Howard Sand & Gravel Incorporated → Mardela Springs-MD SG; 1950-01-01 to 2024-05-16; source msha-controller-operator-history
- **controller_controls_mine:** Beach J Douglas → Mardela Springs-MD SG; 1950-01-01 to 2021-04-13; source msha-controller-operator-history
- **controller_controls_operator:** Beach J Douglas → Howard Sand & Gravel Incorporated; 1950-01-01 to 2021-04-13; source msha-controller-operator-history
- **controller_controls_mine:** Joseph D  Beach Jr → Mardela Springs-MD SG; 2021-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph D  Beach Jr → Howard Sand & Gravel Incorporated; 2021-04-14 to 2024-05-16; source msha-controller-operator-history
- **controller_controls_mine:** Chaney Enterprises LP → Mardela Springs-MD SG; 2024-03-25 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sustainable Land Use, LLC → Mardela Springs-MD SG; 2024-05-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chaney Enterprises LP → Sustainable Land Use, LLC; 2024-05-17 to current/open; source msha-controller-operator-history