# Relationship history for MSHA mine 4607022

Current hierarchy: **Hawkins Denver A → Big Grassy Creek Coal Company → Grassy Creek #1 Preparation Plant**

- 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:** Hawkins Denver A Et Al → Grassy Creek #1 Preparation Plant; 1985-07-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sgp Processing Inc → Grassy Creek #1 Preparation Plant; 1985-10-01 to 1986-08-07; source msha-controller-operator-history
- **controller_controls_mine:** Permenter Dan A → Grassy Creek #1 Preparation Plant; 1985-10-01 to 1986-08-07; source msha-controller-operator-history
- **controller_controls_operator:** Permenter Dan A → Sgp Processing Inc; 1985-10-01 to 1986-08-07; source msha-controller-operator-history
- **operator_operates_mine:** Big Grassy Creek Coal Company → Grassy Creek #1 Preparation Plant; 1986-08-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hawkins Denver A Et Al → Big Grassy Creek Coal Company; 1986-08-08 to current/open; source msha-controller-operator-history