# Relationship history for MSHA mine 2700336

Current hierarchy: **Amrize Ltd → AGGREGATE INDUSTRIES NORTHEAST REGION → NEW BOSTON PIT**

- 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:** R David  Schelzi → NEW BOSTON PIT; 1979-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Wakefield Materials Corp → NEW BOSTON PIT; 1999-04-01 to 2002-09-05; source msha-controller-operator-history
- **controller_controls_operator:** R David  Schelzi → Wakefield Materials Corp; 1999-04-01 to 2002-09-05; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → NEW BOSTON PIT; 2001-06-01 to 2009-04-29; source msha-controller-operator-history
- **operator_operates_mine:** AGGREGATE INDUSTRIES NORTHEAST REGION → NEW BOSTON PIT; 2002-09-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → AGGREGATE INDUSTRIES NORTHEAST REGION; 2002-09-06 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → NEW BOSTON PIT; 2009-04-30 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → AGGREGATE INDUSTRIES NORTHEAST REGION; 2009-04-30 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → NEW BOSTON PIT; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → AGGREGATE INDUSTRIES NORTHEAST REGION; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Amrize Ltd → NEW BOSTON PIT; 2025-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → AGGREGATE INDUSTRIES NORTHEAST REGION; 2025-06-23 to current/open; source msha-controller-operator-history