# Relationship history for MSHA mine 2002791

Current hierarchy: **Donald J  Fennema → South Kent Gravel Inc → Riverside 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:** Donald J  Fennema → Riverside Pit; 1981-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** South Kent Gravel Inc → Riverside Pit; 1987-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald J  Fennema → South Kent Gravel Inc; 1987-07-01 to current/open; source msha-controller-operator-history