# Relationship history for MSHA mine 1516592

Current hierarchy: **Smith Cynthia A → Drift Mining Company → Drift #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

- **controller_controls_mine:** Hobart  Anderson  et al → Drift #1; 1986-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Preece Kelly → Drift #1; 1989-01-10 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mentor Mining Inc → Drift #1; 1989-03-01 to 1989-10-26; source msha-controller-operator-history
- **controller_controls_operator:** Preece Kelly → Mentor Mining Inc; 1989-03-01 to 1989-10-26; source msha-controller-operator-history
- **controller_controls_mine:** Frazier Robert B → Drift #1; 1989-10-19 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Beaver Mining Inc → Drift #1; 1989-10-27 to 1990-02-06; source msha-controller-operator-history
- **controller_controls_operator:** Frazier Robert B → Beaver Mining Inc; 1989-10-27 to 1990-02-06; source msha-controller-operator-history
- **operator_operates_mine:** Big Ten Coal Company Inc → Drift #1; 1990-02-07 to 1990-08-07; source msha-controller-operator-history
- **controller_controls_mine:** Skeens Stanley → Drift #1; 1990-02-07 to 1990-08-07; source msha-controller-operator-history
- **controller_controls_operator:** Skeens Stanley → Big Ten Coal Company Inc; 1990-02-07 to 1990-08-07; source msha-controller-operator-history
- **operator_operates_mine:** Spurlock Mining Company Inc → Drift #1; 1990-08-08 to 1992-01-14; source msha-controller-operator-history
- **controller_controls_operator:** Hobart  Anderson  et al → Spurlock Mining Company Inc; 1990-08-08 to 1992-01-14; source msha-controller-operator-history
- **operator_operates_mine:** Drift Mining Company → Drift #1; 1992-01-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Smith Cynthia A → Drift #1; 1992-01-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Cynthia A → Drift Mining Company; 1992-01-15 to current/open; source msha-controller-operator-history