# Relationship history for MSHA mine 0404975

Current hierarchy: **Bob  Ford; Rob  Ford → Bob Ford & Son → Trinity Quarry**

- 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:** Bob Ford & Son → Trinity Quarry; 1988-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bob  Ford  et al → Trinity Quarry; 1988-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bob  Ford  et al → Bob Ford & Son; 1988-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rob  Ford  et al → Bob Ford & Son; 1988-10-01 to current/open; source msha-controller-operator-history