# Relationship history for MSHA mine 3608878

Current hierarchy: **Heidelberg Materials AG → Better Materials Corp → Springfield Pike Surface 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

- **controller_controls_mine:** USS Holdings Inc → Springfield Pike Surface Quarry; 1996-03-09 to 2003-07-18; source msha-controller-operator-history
- **operator_operates_mine:** Better Materials Corp → Springfield Pike Surface Quarry; 2000-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USS Holdings Inc → Better Materials Corp; 2000-08-01 to 2003-07-18; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Springfield Pike Surface Quarry; 2003-07-19 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Better Materials Corp; 2003-07-19 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Springfield Pike Surface Quarry; 2007-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Better Materials Corp; 2007-08-23 to current/open; source msha-controller-operator-history