# Relationship history for MSHA mine 1601047

Current hierarchy: **Robert Q  Humble → Century Ready-Mix Corporation → Montgomery Pit**

- 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:** H H  Holloway Jr → Montgomery Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert Q  Humble  et al → Montgomery Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Monroe Sand & Gravel Company Inc → Montgomery Pit; 1984-07-01 to 1997-07-31; source msha-controller-operator-history
- **controller_controls_operator:** H H  Holloway Jr → Monroe Sand & Gravel Company Inc; 1984-07-01 to 1997-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Century Ready-Mix Corporation → Montgomery Pit; 1997-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert Q  Humble  et al → Century Ready-Mix Corporation; 1997-08-01 to current/open; source msha-controller-operator-history