# Relationship history for MSHA mine 3101988

Current hierarchy: **Blocker Eddie Iii → Sand Products → Industrial Sand 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Sand Blasting Products Company Inc → Industrial Sand Plant; 1985-08-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Sand Blasting Products Company Inc → Industrial Sand Plant; 1985-08-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Sand Blasting Products Company Inc → Sand Blasting Products Company Inc; 1985-08-01 to 1986-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Osborne Sand Products Company → Industrial Sand Plant; 1986-03-01 to 1986-10-05; source msha-controller-operator-history
- **controller_controls_mine:** Osborne Donald Ray → Industrial Sand Plant; 1986-03-01 to 1986-10-05; source msha-controller-operator-history
- **controller_controls_operator:** Osborne Donald Ray → Osborne Sand Products Company; 1986-03-01 to 1986-10-05; source msha-controller-operator-history
- **operator_operates_mine:** Sand Products → Industrial Sand Plant; 1986-10-06 to 1989-05-14; source msha-controller-operator-history
- **controller_controls_mine:** William L Whitehead → Industrial Sand Plant; 1986-10-06 to 1989-05-14; source msha-controller-operator-history
- **controller_controls_operator:** William L Whitehead → Sand Products; 1986-10-06 to 1989-05-14; source msha-controller-operator-history
- **operator_operates_mine:** Sand Products → Industrial Sand Plant; 1989-05-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Blocker Eddie Iii → Industrial Sand Plant; 1989-05-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blocker Eddie Iii → Sand Products; 1989-05-15 to current/open; source msha-controller-operator-history