# Relationship history for MSHA mine 3102220

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Inc → Black Ankle 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 → Black Ankle Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Little River Stone LLC → Black Ankle Quarry; 2006-08-18 to 2008-03-26; source msha-controller-operator-history
- **controller_controls_mine:** Richard L  Kern et al → Black Ankle Quarry; 2006-08-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard L  Kern et al → Little River Stone LLC; 2006-08-18 to 2008-03-26; source msha-controller-operator-history
- **controller_controls_operator:** Leonard H  Kern et al → Little River Stone LLC; 2006-08-18 to 2008-03-26; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Inc → Black Ankle Quarry; 2008-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Inc; 2008-03-27 to current/open; source msha-controller-operator-history