# Relationship history for MSHA mine 4103060

Current hierarchy: **Martin Marietta Materials Inc → Hanson Aggregates LLC → Spring Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** James E  Welch et al → Spring Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pioneer International Ltd → Spring Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Welch & Welch Sand & Gravel Inc → Spring Plant; 1981-03-01 to 1985-03-31; source msha-controller-operator-history
- **controller_controls_operator:** James E  Welch et al → Welch & Welch Sand & Gravel Inc; 1981-03-01 to 1985-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Evelyn  Welch et al → Welch & Welch Sand & Gravel Inc; 1981-03-01 to 1985-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Concrete Of Texas Inc → Spring Plant; 1985-04-01 to 1989-12-18; source msha-controller-operator-history
- **controller_controls_operator:** Pioneer International Ltd → Pioneer Concrete Of Texas Inc; 1985-04-01 to 1989-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Spring Plant; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Liberty Materials Inc → Spring Plant; 1989-12-19 to 2000-08-03; source msha-controller-operator-history
- **controller_controls_mine:** James E  Welch et al → Spring Plant; 1989-12-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James E  Welch et al → Liberty Materials Inc; 1989-12-19 to 2000-08-03; source msha-controller-operator-history
- **controller_controls_operator:** Evelyn  Welch et al → Liberty Materials Inc; 1989-12-19 to 2000-08-03; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates Central Inc → Spring Plant; 2000-08-04 to 2004-05-09; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Spring Plant; 2000-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates Central Inc; 2000-08-04 to 2004-05-09; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates LLC → Spring Plant; 2004-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates LLC; 2004-05-10 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Spring Plant; 2007-08-23 to 2021-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Hanson Aggregates LLC; 2007-08-23 to 2021-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Spring Plant; 2021-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Hanson Aggregates LLC; 2021-10-01 to current/open; source msha-controller-operator-history