# Relationship history for MSHA mine 4406505

Current hierarchy: **Progress Energy Inc → Powell Mountain Coal Company Inc → Darby #1**

- 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

- **controller_controls_mine:** Amvest Corporation → Darby #1; 1981-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Darby Coal Corp → Darby #1; 1989-03-01 to 1990-03-28; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Nichols → Darby #1; 1989-03-01 to 1990-03-28; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Nichols → Darby Coal Corp; 1989-03-01 to 1990-03-28; source msha-controller-operator-history
- **operator_operates_mine:** Denco Inc → Darby #1; 1990-03-29 to 1991-07-11; source msha-controller-operator-history
- **controller_controls_mine:** Goodman Eddie → Darby #1; 1990-03-29 to 1991-07-11; source msha-controller-operator-history
- **controller_controls_operator:** Goodman Eddie → Denco Inc; 1990-03-29 to 1991-07-11; source msha-controller-operator-history
- **controller_controls_mine:** Gipson James A → Darby #1; 1990-05-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ag Mining Inc → Darby #1; 1991-07-12 to 1992-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Gipson James A → Ag Mining Inc; 1991-07-12 to 1992-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Powell Mountain Coal Company Inc → Darby #1; 1992-02-01 to 1992-08-12; source msha-controller-operator-history
- **controller_controls_operator:** Amvest Corporation → Powell Mountain Coal Company Inc; 1992-02-01 to 1992-08-12; source msha-controller-operator-history
- **operator_operates_mine:** Brett Enterprises Inc → Darby #1; 1992-08-13 to 1995-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Clayburne Jeff → Darby #1; 1992-08-13 to 1995-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Clayburne Jeff → Brett Enterprises Inc; 1992-08-13 to 1995-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Powell Mountain Coal Company Inc → Darby #1; 1995-03-01 to 1997-09-24; source msha-controller-operator-history
- **controller_controls_operator:** Amvest Corporation → Powell Mountain Coal Company Inc; 1995-03-01 to 1997-09-24; source msha-controller-operator-history
- **operator_operates_mine:** Powell Mountain Coal Company Inc → Darby #1; 1997-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Progress Energy Inc → Darby #1; 2000-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Progress Energy Inc → Powell Mountain Coal Company Inc; 2000-11-30 to current/open; source msha-controller-operator-history