# Relationship history for MSHA mine 2301641

Current hierarchy: **William D  Martz → Riverside Sand Company → B J 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:** B B'S Sand Company Inc → B J PLANT; 1950-01-01 to 1988-03-15; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Wilson → B J PLANT; 1950-01-01 to 1988-03-15; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Wilson → B B'S Sand Company Inc; 1950-01-01 to 1988-03-15; source msha-controller-operator-history
- **operator_operates_mine:** Riverside Sand Company → B J PLANT; 1988-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William D  Martz → B J PLANT; 1988-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William D  Martz → Riverside Sand Company; 1988-03-16 to current/open; source msha-controller-operator-history