# Relationship history for MSHA mine 3600136

Current hierarchy: **Heidelberg Materials AG → Essroc Cement Corporation → Essroc Cement Corp Plant #3**

- 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:** Nazareth Cement Corp → Essroc Cement Corp Plant #3; 1950-01-01 to 1994-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Lone Star Industries Inc → Essroc Cement Corp Plant #3; 1950-01-01 to 1994-12-19; source msha-controller-operator-history
- **controller_controls_operator:** Lone Star Industries Inc → Nazareth Cement Corp; 1950-01-01 to 1994-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Italcementi Spa → Essroc Cement Corp Plant #3; 1950-01-01 to 2016-10-11; source msha-controller-operator-history
- **operator_operates_mine:** Essroc Cement Corporation → Essroc Cement Corp Plant #3; 1994-12-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Italcementi Spa → Essroc Cement Corporation; 1994-12-20 to 2016-10-11; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Essroc Cement Corp Plant #3; 2016-10-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Essroc Cement Corporation; 2016-10-12 to current/open; source msha-controller-operator-history