# Relationship history for MSHA mine 0102950

Current hierarchy: **Edward J  Serda → Mobile Abrasives, Inc. → Mobile Abrasives, Inc.**

- 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:** Clark Sand Company Inc → Mobile Abrasives, Inc.; 1992-03-01 to 1996-08-09; source msha-controller-operator-history
- **controller_controls_mine:** John R  Clark  et al → Mobile Abrasives, Inc.; 1992-03-01 to 1996-08-09; source msha-controller-operator-history
- **controller_controls_operator:** John R  Clark  et al → Clark Sand Company Inc; 1992-03-01 to 1996-08-09; source msha-controller-operator-history
- **operator_operates_mine:** Mobile Abrasives → Mobile Abrasives, Inc.; 1996-08-10 to 2002-03-10; source msha-controller-operator-history
- **controller_controls_mine:** Fairmount Santrol → Mobile Abrasives, Inc.; 1996-08-10 to 2002-03-10; source msha-controller-operator-history
- **controller_controls_operator:** Fairmount Santrol → Mobile Abrasives; 1996-08-10 to 2002-03-10; source msha-controller-operator-history
- **operator_operates_mine:** Mobile Abrasives, Inc. → Mobile Abrasives, Inc.; 2002-03-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Edward J  Serda → Mobile Abrasives, Inc.; 2002-03-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward J  Serda → Mobile Abrasives, Inc.; 2002-03-11 to current/open; source msha-controller-operator-history