# Relationship history for MSHA mine 4406636

Current hierarchy: **James A  Sigmon → Sigmon Coal Company Inc → No 2 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 A  Sigmon → No 2 Mine; 1985-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hicks Robert A → No 2 Mine; 1990-12-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James C  Ball → No 2 Mine; 1991-09-01 to 1994-08-29; source msha-controller-operator-history
- **operator_operates_mine:** Sigmon Coal Company Inc → No 2 Mine; 1992-03-02 to 1993-01-05; source msha-controller-operator-history
- **controller_controls_operator:** James A  Sigmon → Sigmon Coal Company Inc; 1992-03-02 to 1993-01-05; source msha-controller-operator-history
- **operator_operates_mine:** Big Dog Coal Company Inc → No 2 Mine; 1993-01-06 to 1993-06-24; source msha-controller-operator-history
- **controller_controls_operator:** Hicks Robert A → Big Dog Coal Company Inc; 1993-01-06 to 1993-06-24; source msha-controller-operator-history
- **operator_operates_mine:** Cola Coal Company Inc → No 2 Mine; 1993-06-25 to 1994-08-29; source msha-controller-operator-history
- **controller_controls_operator:** James C  Ball → Cola Coal Company Inc; 1993-06-25 to 1994-08-29; source msha-controller-operator-history
- **operator_operates_mine:** Sigmon Coal Company Inc → No 2 Mine; 1994-08-30 to 1995-03-13; source msha-controller-operator-history
- **controller_controls_operator:** James A  Sigmon → Sigmon Coal Company Inc; 1994-08-30 to 1995-03-13; source msha-controller-operator-history
- **operator_operates_mine:** Industrial Energy Corp → No 2 Mine; 1995-03-14 to 1996-02-13; source msha-controller-operator-history
- **controller_controls_mine:** Barnwell Darrell G → No 2 Mine; 1995-03-14 to 1996-02-13; source msha-controller-operator-history
- **controller_controls_operator:** Barnwell Darrell G → Industrial Energy Corp; 1995-03-14 to 1996-02-13; source msha-controller-operator-history
- **operator_operates_mine:** Sigmon Coal Company Inc → No 2 Mine; 1996-02-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James A  Sigmon → Sigmon Coal Company Inc; 1996-02-14 to current/open; source msha-controller-operator-history