# Relationship history for MSHA mine 2600081

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Apex Quarry and 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:** Martin Marietta Materials Inc → Apex Quarry and Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Flintkote Company → Apex Quarry and Plant; 1950-01-01 to 1980-04-06; source msha-controller-operator-history
- **controller_controls_mine:** Flintkote Company → Apex Quarry and Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Flintkote Company → Flintkote Company; 1950-01-01 to 1980-04-06; source msha-controller-operator-history
- **operator_operates_mine:** Genstar Lime Company → Apex Quarry and Plant; 1980-04-07 to 1986-12-03; source msha-controller-operator-history
- **controller_controls_mine:** Cimenteries Cbr Cementbedrijven → Apex Quarry and Plant; 1980-04-07 to 1986-12-03; source msha-controller-operator-history
- **controller_controls_operator:** Cimenteries Cbr Cementbedrijven → Genstar Lime Company; 1980-04-07 to 1986-12-03; source msha-controller-operator-history
- **operator_operates_mine:** Lhoist North America of Arizona Inc. → Apex Quarry and Plant; 1986-12-04 to 2026-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Chemical Lime Company → Apex Quarry and Plant; 1986-12-04 to 1998-12-30; source msha-controller-operator-history
- **controller_controls_operator:** Chemical Lime Company → Lhoist North America of Arizona Inc.; 1986-12-04 to 1998-12-30; source msha-controller-operator-history
- **controller_controls_mine:** Lhoist Group → Apex Quarry and Plant; 1998-12-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lhoist Group → Lhoist North America of Arizona Inc.; 1998-12-31 to 2026-09-14; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Apex Quarry and Plant; 2026-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2026-09-15 to current/open; source msha-controller-operator-history