# Relationship history for MSHA mine 0900892

Current hierarchy: **Julia  Campbell; Andrew  Campbell et  al → Blackhill Granites LLC → Greene Co Quarry**

- 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:** William  Swift et al → Greene Co Quarry; 1950-01-01 to 2020-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Mercer Granite Company → Greene Co Quarry; 1979-01-01 to 1991-05-09; source msha-controller-operator-history
- **controller_controls_mine:** Henry Thomas  Mercer  et al → Greene Co Quarry; 1979-01-01 to 1991-05-09; source msha-controller-operator-history
- **controller_controls_operator:** Henry Thomas  Mercer  et al → Mercer Granite Company; 1979-01-01 to 1991-05-09; source msha-controller-operator-history
- **operator_operates_mine:** Green County Quarries Inc → Greene Co Quarry; 1991-05-10 to 2002-08-31; source msha-controller-operator-history
- **controller_controls_mine:** James A  Adams  et al → Greene Co Quarry; 1991-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James A  Adams  et al → Green County Quarries Inc; 1991-05-10 to 2002-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Eric  Higginbotham → Greene Co Quarry; 2000-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** NCGC of GA → Greene Co Quarry; 2002-09-01 to 2006-03-14; source msha-controller-operator-history
- **controller_controls_mine:** William  Swift et al → Greene Co Quarry; 2002-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William  Swift et al → NCGC of GA; 2002-09-01 to 2006-03-14; source msha-controller-operator-history
- **operator_operates_mine:** Specialty Stone Services → Greene Co Quarry; 2006-03-15 to 2014-04-28; source msha-controller-operator-history
- **controller_controls_operator:** Eric  Higginbotham → Specialty Stone Services; 2006-03-15 to 2014-04-28; source msha-controller-operator-history
- **operator_operates_mine:** North Carolina Granite Corp → Greene Co Quarry; 2014-04-29 to 2018-07-22; source msha-controller-operator-history
- **controller_controls_operator:** William  Swift et al → North Carolina Granite Corp; 2014-04-29 to 2018-07-22; source msha-controller-operator-history
- **operator_operates_mine:** Gibson Contract Services of Elberton, LLC → Greene Co Quarry; 2018-07-23 to 2026-01-07; source msha-controller-operator-history
- **controller_controls_mine:** Sherry Lynn  Gibson → Greene Co Quarry; 2018-07-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sherry Lynn  Gibson → Gibson Contract Services of Elberton, LLC; 2018-07-23 to 2026-01-07; source msha-controller-operator-history
- **controller_controls_mine:** Polycor Inc → Greene Co Quarry; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Polycor Inc → North Carolina Granite Corp; 2021-01-01 to 2018-07-22; source msha-controller-operator-history
- **operator_operates_mine:** Blackhill Granites LLC → Greene Co Quarry; 2026-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Andrew  Campbell et  al → Greene Co Quarry; 2026-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Andrew  Campbell et  al → Blackhill Granites LLC; 2026-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Julia  Campbell et al → Blackhill Granites LLC; 2026-01-08 to current/open; source msha-controller-operator-history