# Relationship history for MSHA mine 4403808

Current hierarchy: **Amvest Corporation → Glamorgan Coal Company → Norton #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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Porter Coal Company → Norton #1; 1974-01-01 to 1987-04-14; source msha-controller-operator-history
- **controller_controls_mine:** Amvest Corporation → Norton #1; 1974-01-01 to 1994-09-11; source msha-controller-operator-history
- **controller_controls_operator:** Amvest Corporation → Porter Coal Company; 1974-01-01 to 1987-04-14; source msha-controller-operator-history
- **controller_controls_mine:** Amvest Corporation → Norton #1; 1976-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Fred  McGlothlin et al → Norton #1; 1985-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** L B J Energy Inc → Norton #1; 1987-04-15 to 1994-06-27; source msha-controller-operator-history
- **controller_controls_operator:** Fred  McGlothlin et al → L B J Energy Inc; 1987-04-15 to 1994-06-27; source msha-controller-operator-history
- **operator_operates_mine:** Porter Coal Company → Norton #1; 1994-06-28 to 1994-09-11; source msha-controller-operator-history
- **controller_controls_operator:** Amvest Corporation → Porter Coal Company; 1994-06-28 to 1994-09-11; source msha-controller-operator-history
- **operator_operates_mine:** Sunny Side Coal Inc → Norton #1; 1994-09-12 to 1997-11-09; source msha-controller-operator-history
- **controller_controls_mine:** (William) Scott  Moore → Norton #1; 1994-09-12 to 1998-02-15; source msha-controller-operator-history
- **controller_controls_operator:** (William) Scott  Moore → Sunny Side Coal Inc; 1994-09-12 to 1997-11-09; source msha-controller-operator-history
- **operator_operates_mine:** Glamorgan Coal Company → Norton #1; 1997-11-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amvest Corporation → Glamorgan Coal Company; 1997-11-10 to current/open; source msha-controller-operator-history