# Relationship history for MSHA mine 2501061

Current hierarchy: **Richard J  Follmer → T&F Sand & Gravel Inc. → Odessa**

- 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:** Roland C  Whitney → Odessa; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard J  Follmer → Odessa; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Carl Whitney Sand & Gravel Inc → Odessa; 1986-05-01 to 2018-11-04; source msha-controller-operator-history
- **controller_controls_operator:** Roland C  Whitney → Carl Whitney Sand & Gravel Inc; 1986-05-01 to 2018-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Ronald L  Follmer et al → Odessa; 2000-05-11 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mid-Nebraska Aggregate Inc. → Odessa; 2018-11-05 to 2019-04-07; source msha-controller-operator-history
- **controller_controls_operator:** Ronald L  Follmer et al → Mid-Nebraska Aggregate Inc.; 2018-11-05 to 2019-04-07; source msha-controller-operator-history
- **operator_operates_mine:** T&F Sand & Gravel Inc. → Odessa; 2019-04-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard J  Follmer → T&F Sand & Gravel Inc.; 2019-04-08 to current/open; source msha-controller-operator-history