# Relationship history for MSHA mine 3901377

Current hierarchy: **Bill  Boyer → Boyer Sand & Rock Inc → NORTH PIT**

- 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:** Boyer Sand & Rock Inc → NORTH PIT; 1990-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Boyer → NORTH PIT; 1990-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Boyer → Boyer Sand & Rock Inc; 1990-06-01 to current/open; source msha-controller-operator-history