# Relationship history for MSHA mine 3002517

Current hierarchy: **Dave  Burrell → BURRELL'S EXCAVATING INC → NORWICH**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Du Bois Sand & Gravel → NORWICH; 1980-05-01 to 1981-03-18; source msha-controller-operator-history
- **controller_controls_mine:** Dick  Du Bois → NORWICH; 1980-05-01 to 1981-03-18; source msha-controller-operator-history
- **controller_controls_operator:** Dick  Du Bois → Du Bois Sand & Gravel; 1980-05-01 to 1981-03-18; source msha-controller-operator-history
- **operator_operates_mine:** Lynk Construction → NORWICH; 1981-03-19 to 1984-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Lynk Gary A → NORWICH; 1981-03-19 to 1984-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Lynk Gary A → Lynk Construction; 1981-03-19 to 1984-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Gorton Construction Company → NORWICH; 1984-07-01 to 1997-10-22; source msha-controller-operator-history
- **controller_controls_mine:** Mc Nitt James → NORWICH; 1984-07-01 to 1997-10-22; source msha-controller-operator-history
- **controller_controls_operator:** Mc Nitt James → Gorton Construction Company; 1984-07-01 to 1997-10-22; source msha-controller-operator-history
- **operator_operates_mine:** J B M Construction Company → NORWICH; 1997-10-23 to 2005-08-08; source msha-controller-operator-history
- **controller_controls_mine:** Barbara E  Ryan → NORWICH; 1997-10-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barbara E  Ryan → J B M Construction Company; 1997-10-23 to 2005-08-08; source msha-controller-operator-history
- **controller_controls_mine:** Dave  Burrell  et al → NORWICH; 1999-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Burrell's Excavating Inc → NORWICH; 2005-08-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dave  Burrell  et al → Burrell's Excavating Inc; 2005-08-09 to current/open; source msha-controller-operator-history