# Relationship history for MSHA mine 0403762

Current hierarchy: **West Coast Sand & Gravel Inc → J F & T Sand Company → Maitri Plant**

- 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:** J F & T Sand Company → Maitri Plant; 1950-01-01 to 1981-03-24; source msha-controller-operator-history
- **controller_controls_mine:** Turner Arnold → Maitri Plant; 1950-01-01 to 1981-03-24; source msha-controller-operator-history
- **controller_controls_operator:** Turner Arnold → J F & T Sand Company; 1950-01-01 to 1981-03-24; source msha-controller-operator-history
- **operator_operates_mine:** J F & T Sand Company → Maitri Plant; 1981-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** West Coast Sand & Gravel Inc → Maitri Plant; 1981-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** West Coast Sand & Gravel Inc → J F & T Sand Company; 1981-03-25 to current/open; source msha-controller-operator-history