# Relationship history for MSHA mine 1401026

Current hierarchy: **Marc D  Westhoff → Sterling Sand & Gravel → STERLING SAND PIT**

- 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:** Tobias & Birchenough Inc → STERLING SAND PIT; 1950-01-01 to 1985-02-28; source msha-controller-operator-history
- **controller_controls_mine:** John H  Middleton → STERLING SAND PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John H  Middleton → Tobias & Birchenough Inc; 1950-01-01 to 1985-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel → STERLING SAND PIT; 1985-03-01 to 1991-04-14; source msha-controller-operator-history
- **controller_controls_mine:** James O  Campbell → STERLING SAND PIT; 1985-03-01 to 1991-04-14; source msha-controller-operator-history
- **controller_controls_operator:** James O  Campbell → Sterling Sand & Gravel; 1985-03-01 to 1991-04-14; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel → STERLING SAND PIT; 1991-04-15 to 1999-09-22; source msha-controller-operator-history
- **controller_controls_mine:** Edward N  Altvater → STERLING SAND PIT; 1991-04-15 to 1999-09-22; source msha-controller-operator-history
- **controller_controls_operator:** Edward N  Altvater → Sterling Sand & Gravel; 1991-04-15 to 1999-09-22; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel → STERLING SAND PIT; 1999-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Marc D  Westhoff → STERLING SAND PIT; 1999-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marc D  Westhoff → Sterling Sand & Gravel; 1999-09-23 to current/open; source msha-controller-operator-history