# Relationship history for MSHA mine 4202177

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Milford 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:** Martin Marietta Materials Inc → Milford Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Peter Kiewit Sons' Inc → Milford Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Twin Mountain Rock Company → Milford Quarry; 1997-05-01 to 2002-09-25; source msha-controller-operator-history
- **controller_controls_operator:** Peter Kiewit Sons' Inc → Twin Mountain Rock Company; 1997-05-01 to 2002-09-25; source msha-controller-operator-history
- **operator_operates_mine:** Rinker Materials Western Inc. → Milford Quarry; 2002-09-26 to 2008-11-16; source msha-controller-operator-history
- **controller_controls_mine:** CSR Ltd → Milford Quarry; 2002-09-26 to 2003-03-31; source msha-controller-operator-history
- **controller_controls_operator:** CSR Ltd → Rinker Materials Western Inc.; 2002-09-26 to 2003-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Rinker Group Ltd → Milford Quarry; 2003-04-01 to 2007-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Rinker Group Ltd → Rinker Materials Western Inc.; 2003-04-01 to 2007-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Cemex S A → Milford Quarry; 2007-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cemex S A → Rinker Materials Western Inc.; 2007-07-10 to 2008-11-16; source msha-controller-operator-history
- **controller_controls_mine:** Cemex S A → Milford Quarry; 2008-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** CEMEX Construction Materials South LLC → Milford Quarry; 2008-11-17 to 2009-06-14; source msha-controller-operator-history
- **controller_controls_operator:** Cemex S A → CEMEX Construction Materials South LLC; 2008-11-17 to 2009-06-14; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Milford Quarry; 2009-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2009-06-15 to current/open; source msha-controller-operator-history