Key Takeaway

Superior - Twin Oaks is a active surface mine producing Stone, located in San Marcos, San Diego County, CA. It has 194 violations on record (59 S&S) and $66K in proposed penalties. Operated by Superior Ready Mix Concrete L.P..

Superior - Twin Oaks

Active Surface Stone

Operator: Superior Ready Mix Concrete L.P.

Controller: Vulcan Materials Company

Location: San Marcos, San Diego County, CA

Employees: 7

194
Violations
59
S&S Violations
8
Accidents
$66K
Penalties

Recent Violations

View all 194 →
Date Section S&S Negligence Penalty
06/25/2025 56.14112(a)(1) Non-S&S LowNegligence $151
06/25/2025 56.12032 Non-S&S LowNegligence $151
06/25/2025 56.20011 S&S ModNegligence $465
06/25/2025 56.12018 Non-S&S LowNegligence $151
06/25/2025 56.12032 Non-S&S ModNegligence $151
01/22/2025 56.12018 Non-S&S ModNegligence $642
11/28/2023 56.12004 Non-S&S ModNegligence $143
11/28/2023 56.14107(a) Non-S&S HighNegligence $143
11/28/2023 56.14111(b) Non-S&S ModNegligence $143
11/28/2023 56.20011 S&S ModNegligence $518
11/28/2023 46.7(a) S&S ModNegligence $576
11/28/2023 56.14110 S&S ModNegligence $155
11/28/2023 56.4130(b) Non-S&S ModNegligence $143
11/28/2023 56.14112(a)(1) Non-S&S LowNegligence $143
11/28/2023 56.13015(a) Non-S&S ModNegligence $143
11/28/2023 46.7(a) S&S ModNegligence $576
06/15/2023 56.12032 Non-S&S LowNegligence $143
06/15/2023 56.12004 Non-S&S LowNegligence $143
03/22/2023 56.14112(a)(2) Non-S&S LowNegligence $143
03/22/2023 56.11001 S&S ModNegligence $518

Accidents & Injuries

View all 8 →
Date Classification Injury Days Lost
04/25/2025 HANDLING OF MATERIALS DYS AWY FRM WRK & RESTRCTD ACT 128d lost, 9d restricted
11/21/2024 SLIP OR FALL OF PERSON DYS AWY FRM WRK & RESTRCTD ACT 35d lost, 11d restricted
07/01/2022 SLIP OR FALL OF PERSON DYS AWY FRM WRK & RESTRCTD ACT 21d lost, 60d restricted
12/30/2021 SLIP OR FALL OF PERSON DAYS AWAY FROM WORK ONLY None
08/18/2009 SLIP OR FALL OF PERSON DAYS AWAY FROM WORK ONLY 88d lost
02/06/2007 POWERED HAULAGE DAYS AWAY FROM WORK ONLY 18d lost
07/20/2006 SLIP OR FALL OF PERSON DAYS AWAY FROM WORK ONLY 11d lost
05/17/2005 HANDTOOLS (NONPOWERED) DAYS AWAY FROM WORK ONLY 2d lost

Inspections

View all 68 →
Begin End Hours Inspectors
03/03/2026 0.00 0
06/24/2025 06/26/2025 26.00 1
01/21/2025 01/23/2025 28.50 1
06/10/2024 06/11/2024 14.50 1
11/29/2023 11/29/2023 6.00 1
11/27/2023 11/29/2023 28.50 1
06/14/2023 06/20/2023 15.00 1
03/21/2023 03/22/2023 19.75 1
08/08/2022 08/10/2022 16.25 1
01/04/2022 01/05/2022 22.75 1

Mine Details

MSHA Mine ID0405514
Mine TypeSurface
StatusActive
CommodityStone
SIC DescriptionCrushed, Broken Stone NEC
Employees7
Days/Week5.0
Hours/Shift8.0
Coordinates33.2308330, -117.1811110
Nearest TownSan Marcos

Frequently Asked Questions

How many MSHA violations does Superior - Twin Oaks have?

Superior - Twin Oaks has 194 MSHA violations on record, of which 59 are classified as Significant & Substantial (S&S). Total proposed penalties amount to $66K.

What type of mine is Superior - Twin Oaks?

Superior - Twin Oaks is a Surface mine producing Stone, located in San Marcos, San Diego County, CA. It currently has 7 employees.

Has anyone been injured or killed at Superior - Twin Oaks?

According to MSHA records, Superior - Twin Oaks has 8 reported accident/injury records and 0 fatalities on file.

Who operates Superior - Twin Oaks?

Superior - Twin Oaks is operated by Superior Ready Mix Concrete L.P. and controlled by Vulcan Materials Company. MSHA Mine ID: 0405514.