# Relationship history for MSHA mine 1102591

Current hierarchy: **Albert E  Markgraf → Markgraf Materials Company → Markgraf Materials Company**

- 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:** Jordan Rock & Sand Quarry → Markgraf Materials Company; 1950-01-01 to 1979-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Jordan Donald → Markgraf Materials Company; 1950-01-01 to 1979-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Jordan Donald → Jordan Rock & Sand Quarry; 1950-01-01 to 1979-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Markgraf Materials Company → Markgraf Materials Company; 1979-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Albert E  Markgraf → Markgraf Materials Company; 1979-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Albert E  Markgraf → Markgraf Materials Company; 1979-11-01 to current/open; source msha-controller-operator-history