# Relationship history for MSHA mine 3304279

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → E-Town S&G - 460**

- 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 → E-Town S&G - 460; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Powell Gravel & Topsoil Inc → E-Town S&G - 460; 1992-02-01 to 2001-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Ronald  Powell → E-Town S&G - 460; 1992-02-01 to 2001-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Ronald  Powell → Powell Gravel & Topsoil Inc; 1992-02-01 to 2001-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → E-Town S&G - 460; 2001-03-01 to 2005-05-24; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 2001-03-01 to 2005-05-24; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → E-Town S&G - 460; 2005-05-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2005-05-25 to current/open; source msha-controller-operator-history