# Relationship history for MSHA mine 1506986

Current hierarchy: **Newcomb & Fields Coal Co → Newcomb & Fields Coal Co → No 1 Mine**

- 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:** James E Derry et al → No 1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bentley & Derry Coal Company Inc → No 1 Mine; 1974-01-01 to 1974-07-01; source msha-controller-operator-history
- **controller_controls_operator:** James E Derry et al → Bentley & Derry Coal Company Inc; 1974-01-01 to 1974-07-01; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Derry et al → Bentley & Derry Coal Company Inc; 1974-01-01 to 1974-07-01; source msha-controller-operator-history
- **operator_operates_mine:** Newcomb & Fields Coal Co → No 1 Mine; 1974-07-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Newcomb & Fields Coal Co → No 1 Mine; 1974-07-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Newcomb & Fields Coal Co → Newcomb & Fields Coal Co; 1974-07-02 to current/open; source msha-controller-operator-history