# Relationship history for MSHA mine 3301678

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Troy Gravel**

- 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 → Troy Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Troy Gravel Company → Troy Gravel; 1950-01-01 to 1986-09-17; source msha-controller-operator-history
- **controller_controls_mine:** Henry  Ernst → Troy Gravel; 1950-01-01 to 1986-09-17; source msha-controller-operator-history
- **controller_controls_operator:** Henry  Ernst → Troy Gravel Company; 1950-01-01 to 1986-09-17; source msha-controller-operator-history
- **operator_operates_mine:** Troy Gravel Company → Troy Gravel; 1986-09-18 to 1988-09-07; source msha-controller-operator-history
- **controller_controls_mine:** Ernst Aggregates Inc → Troy Gravel; 1986-09-18 to 1988-09-07; source msha-controller-operator-history
- **controller_controls_operator:** Ernst Aggregates Inc → Troy Gravel Company; 1986-09-18 to 1988-09-07; source msha-controller-operator-history
- **controller_controls_mine:** Consolidated Gold Fields Limited → Troy Gravel; 1988-08-20 to 1989-08-09; source msha-controller-operator-history
- **operator_operates_mine:** Ernst Aggregates → Troy Gravel; 1988-09-08 to 1989-08-09; source msha-controller-operator-history
- **controller_controls_operator:** Consolidated Gold Fields Limited → Ernst Aggregates; 1988-09-08 to 1989-08-09; source msha-controller-operator-history
- **operator_operates_mine:** Ernst Aggregates → Troy Gravel; 1989-08-10 to 1990-02-01; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Troy Gravel; 1989-08-10 to 1990-02-01; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Ernst Aggregates; 1989-08-10 to 1990-02-01; source msha-controller-operator-history
- **operator_operates_mine:** American Aggregates Corp → Troy Gravel; 1990-02-02 to 1997-05-27; source msha-controller-operator-history
- **controller_controls_mine:** CSR Ltd → Troy Gravel; 1990-02-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CSR Ltd → American Aggregates Corp; 1990-02-02 to 1997-05-27; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Troy Gravel; 1997-05-28 to 2005-05-23; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1997-05-28 to 2005-05-23; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Troy Gravel; 2005-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2005-05-24 to current/open; source msha-controller-operator-history