# Relationship history for MSHA mine 1601436

Current hierarchy: **Richard  Richardson → D & J Construction Co., Inc. → D & J Aimwell Sand 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:** Richard  Richardson → D & J Aimwell Sand Pit; 1989-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** D & J Construction Co., Inc. → D & J Aimwell Sand Pit; 2006-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard  Richardson → D & J Construction Co., Inc.; 2006-07-11 to current/open; source msha-controller-operator-history