# Relationship history for MSHA mine 1300205

Current hierarchy: **Mark  Schildberg → Schildberg Construction Company Inc → Jefferson Quarry And Mill**

- 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:** Schildberg Construction Company Inc → Jefferson Quarry And Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark  Schildberg et al → Jefferson Quarry And Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Schildberg et al → Schildberg Construction Company Inc; 1950-01-01 to current/open; source msha-controller-operator-history