# Relationship history for MSHA mine 1701192

Current hierarchy: **Lawrence  Grondin → R.J. Grondin & Sons → Power Screen (M1561)**

- 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:** Robert J  Grondin et al → Power Screen (M1561); 1979-12-01 to 2015-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Lawrence  Grondin et al → Power Screen (M1561); 2015-10-01 to 2022-11-08; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Grondin III et al → Power Screen (M1561); 2022-11-09 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Lawrence  Grondin → Power Screen (M1561); 2024-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R.J. Grondin & Sons → Power Screen (M1561); 2026-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lawrence  Grondin et al → R.J. Grondin & Sons; 2026-06-19 to 2022-11-08; source msha-controller-operator-history
- **controller_controls_operator:** Philip H Grondin Jr et al → R.J. Grondin & Sons; 2026-06-19 to 2022-11-08; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Grondin III et al → R.J. Grondin & Sons; 2026-06-19 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Lawrence  Grondin et al → R.J. Grondin & Sons; 2026-06-19 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Lawrence  Grondin → R.J. Grondin & Sons; 2026-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert J  Grondin et al → R.J. Grondin & Sons; 2026-06-19 to 2015-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth J  Grondin et al → R.J. Grondin & Sons; 2026-06-19 to 2015-09-30; source msha-controller-operator-history