| SMSmoky Mountain Transfer Corporation | Charleston | TN | — | ◇ UNVERIFIED |
| SISolem Industries | Fairmount | GA | — | ◇ UNVERIFIED |
| SCSolite CORP | Cascade | VA | — | ◇ UNVERIFIED |
| SCSoutheastern Clay CO | Aiken | SC | — | ◇ UNVERIFIED |
| SCSouthern Clay Products | Gonzales | TX | — | ◇ UNVERIFIED |
| SSSouth Shore Slag LLC - Contractor of Uss Gary Works (00121) | Gary | IN | — | ◇ UNVERIFIED |
| SMSpecialty Minerals (at Madison Paper) | Madison | ME | — | ◇ UNVERIFIED |
| SMSpecialty Minerals INC | Zachary | LA | — | ◇ UNVERIFIED |
| SMSpecialty Minerals INC | Ashdown | AR | — | ◇ UNVERIFIED |
| SVSpecialty Vermiculite CORP | Enoree | SC | — | ◇ UNVERIFIED |
| SCSpinks Clay Company - Gleason Plant | Gleason | TN | — | ◇ UNVERIFIED |
| SCStandard Corporation Jones Lane | Lugoff | SC | — | ◇ UNVERIFIED |
| SIStandard Industrial Mineral in | Laws | CA | — | ◇ UNVERIFIED |
| SMStandard Mineral Company Incorporated | Robbins | NC | — | ◇ UNVERIFIED |
| SIStein, INC | Birmingham | AL | — | ◇ UNVERIFIED |
| SIStein, INC. (old Harsco Metals) | Tarrant | AL | — | ◇ UNVERIFIED |
| SLStein LLC (1318003929) | Cleveland | OH | — | ◇ UNVERIFIED |
| SCSt-gobain Ceramics & Plastics | Bryant | AR | — | ◇ UNVERIFIED |
| SPStreetman Plant | Streetman | TX | — | ◇ UNVERIFIED |
| SMSully Miller Contracting CO | Irwindale | CA | — | ◇ UNVERIFIED |
| SDSuper Dry Industries INC | Shuqualak | MS | — | ◇ UNVERIFIED |
| SPSupreme Perlite Company | Portland | OR | — | ◇ UNVERIFIED |
| SMSuzorite Mineral Products | Dell City | TX | — | ◇ UNVERIFIED |
 Syrah Technologies LLC - Active Anode Material Facility | Vidalia | LA | — | ◇ UNVERIFIED |
| TLTervita LLC | Rancho Cucamonga | CA | — | ◇ UNVERIFIED |
| TRThe R. J. Marshall Company | Southfield | MI | — | ◇ UNVERIFIED |
| TCThermal Ceramics INC | Girard | IL | — | ◇ UNVERIFIED |
| TMT Minerals LLC - Perlite Expansion Facility | New Orleans | LA | — | ◇ UNVERIFIED |
| TITms International, LLC | Broadview Heights | OH | — | ◇ UNVERIFIED |
| TITms International, LLC | Calvert | AL | — | ◇ UNVERIFIED |
| TATrans Agg,inc. Dba Gibbco, INC. | Lawrenceburg | IN | — | ◇ UNVERIFIED |
| TMTreasure Mine | Dillon | MT | — | ◇ UNVERIFIED |
| TUTrebol USA LLC | Andrews | SC | — | ◇ UNVERIFIED |
| TCTube City Ims, LLC | Middletown | OH | — | ◇ UNVERIFIED |
| TITungco INC | Hanson | KY | — | ◇ UNVERIFIED |
| TTTwo Thousand Fahrenheit INC | Becker | MN | — | ◇ UNVERIFIED |
| TOTxi Operations | Streetman | TX | — | ◇ UNVERIFIED |
| UCUnimin Corporation | Gleason | TN | — | ◇ UNVERIFIED |
 United States Gypsum Company | Spruce Pine | NC | — | ◇ UNVERIFIED |
 Universal Minerals International INC. | Louisville | KY | — | ◇ UNVERIFIED |
| UUrbix | Mesa | AZ | — | ◇ UNVERIFIED |
| USU.s. Silica Company, | Middleton | TN | — | ◇ UNVERIFIED |
| USUS Silica Kosse Plant | Kosse | TX | — | ◇ UNVERIFIED |
| USUS Steel Corporation | Lorain | OH | — | ◇ UNVERIFIED |
| VMVanderbilt Minerals LLC | Bath | SC | — | ◇ UNVERIFIED |
| VCVulcan Const Hanover Quarry & Carmeuse Lime Kilns | Hanover | PA | — | ◇ UNVERIFIED |
| VCVulcan Const Mat LP Anderson Quarry | Anderson | SC | — | ◇ UNVERIFIED |
| VCVulcan Construction Material Limited Partnership Pacolet Quarry | Pacolet | SC | — | ◇ UNVERIFIED |
| WPWa317939649 - Pyrotek Incorporated | Spokane Valley | WA | — | ◇ UNVERIFIED |
| WMWaverly Minerals, INC. | Meigs | GA | — | ◇ UNVERIFIED |
