| Nevada Gold Mines LLC | Elko, NV | 43 |
| Freeport Minerals Corporation | Phoenix, AZ | 42 |
| Freeport-McMoRan Morenci Inc. | Phoenix, AZ | 30 |
| Kennecott Utah Copper LLC | South Jordan, UT | 24 |
| Newmont International Services Limited | Denver, CO | 12 |
| Freeport-McMoRan Bagdad Inc. | Phoenix, AZ | 12 |
| Srk Consulting (U.S.), Inc. | Denver, CO | 12 |
| Resolution Copper Company | Superior, AZ | 11 |
| Stantec Consulting Services Inc. | Denver, CO | 11 |
| RESPEC, Inc. | Rapid City, SD | 10 |
| Climax Molybdenum Company | Phoenix, AZ | 9 |
| ECS Southwest, LLP | Chantilly, VA | 9 |
| Northern Star (POGO) LLC | Fairbanks, AK | 9 |
| Nyrstar Tennessee Mines - Strawberry Plains, LLC | Strawberry Plains, TN | 8 |
| Freeport-McMoRan Safford Inc. | Phoenix, AZ | 8 |
| BHP Minerals Service Company | Tucson, AZ | 8 |
| United Consulting Group Ltd. | Norcross, GA | 8 |
| Halliburton Energy Services, Inc. | Houston, TX | 8 |
| Teck Alaska Incorporated | Anchorage, AK | 7 |
| Asarco LLC | Sahuarita, AZ | 7 |
| Freeport-McMoRan Sierrita Inc. | Phoenix, AZ | 7 |
| Conocophillips Company | Houston, TX | 7 |
| Kiewit Engineering Group Inc. | Omaha, NE | 6 |
| WSP USA Inc. | New York, NY | 6 |
| Itasca Consulting Group, Inc. | Minneapolis, MN | 6 |
| Rio Tinto Services Inc. | South Jordan, UT | 6 |
| Freeport-McMoRan Chino Mines Company | Phoenix, AZ | 6 |
| Barrick Gold of North America, Inc. | Elko, NV | 5 |
| Metallum Global LLC | Columbia, SC | 5 |
| Haile Gold Mine, Inc. | Kershaw, SC | 5 |
| Barminco Mining Services USA LLC | Denver, CO | 5 |
| Haley & Aldrich, Inc. | Burlington, MA | 5 |
| U.S. Borax Inc. | Boron, CA | 5 |
| Nevada Copper Inc. | Yerington, NV | 5 |
| ECS Mid-Atlantic, LLC | Chantilly, VA | 4 |
| Agapito Associates, LLC | Grand Junction, CO | 4 |
| Advanced Mining Professional Services Inc. | Denver, CO | 4 |
| Sibelco North America Inc. | Charlotte, NC | 4 |
| CGG Services (U.S.) Inc. | Houston, TX | 4 |
| Mariana Minerals Co. | San Francisco, CA | 3 |
| GZA GeoEnvironmental of New York | Buffalo, NY | 3 |
| Weeks Marine, Inc. | Omaha, NE | 3 |
| Pinto Valley Mining Corp. | Miami, AZ | 3 |
| Rummel, Klepper & Kahl, LLP | Baltimore, MD | 3 |
| Civil & Environmental Consultants, Inc. | Moon Township, PA | 3 |
| Call & Nicholas, Inc. | Tucson, AZ | 3 |
| Cidra Minerals Processing Inc. | Wallingford, CT | 3 |
| Fugro USA Marine, Inc. | Houston, TX | 3 |
| Western Explosives Systems Company | Slc, UT | 2 |
| F.L. Smidth Inc. | Midvale, UT | 2 |
| Cripple Creek & Victor Gold Mining Co LLC | Denver, CO | 2 |
| SSR Management, Inc. | Denver, CO | 2 |
| BBA Consultants International LP | Wilmington, DE | 2 |
| Vulcan Materials Company | Birmingham, AL | 2 |
| Strata, LLC | Wichita, KS | 2 |
| Schnabel Management Services, Inc. | Glen Allen, VA | 2 |
| Felix Gold Alaska Treasure Creek Inc. | Fairbanks, AK | 2 |
| T.M. Kilduff Consulting, Inc. | Tinton Falls, NJ | 2 |
| KG Mining (Bald Mountain), Inc. | Ely, NV | 2 |
| SLR International Corporation | Bothell, WA | 2 |
| Falcon Services, LLC | Sheridan, WY | 2 |
| Mesabi Metallics Company LLC | Nashwauk, MN | 2 |
| Freeport-McMoRan Tyrone Mining LLC | Tyrone, NM | 2 |
| Prostar Mining LLC | Peoria, IL | 2 |
| Global Resource Engineering, Ltd. | Golden, CO | 2 |
| James River Slate Company, Inc. | Arvonia, VA | 2 |
| Hecla Limited | Coeur D'Alene, ID | 2 |
| Gappsi Inc | Smithtown, NY | 2 |
| WSP USA Environment & Infrastructure Inc. | New York, NY | 2 |
| Garnet Energy Capital, LLC | Houston, TX | 2 |
| OHLA USA, Inc. | East Elmhurst, NY | 2 |
| Nipa Inc. | Santa Ana, CA | 2 |
| Kiewit Infrastructure Co. | Omaha, NE | 2 |
| Gall Zeidler Consultants, LLC | Ashburn, VA | 2 |
| Florida Canyon Mining, Inc. | Imlay, NV | 2 |
| InfoMine USA, Inc. | Spokane Valley, WA | 2 |
| J.F. Shea Construction, Inc. | Walnut, CA | 2 |
| AECOM Technical Services Inc | Dallas, TX | 2 |
| Redpath USA Corporation | Sparks, NV | 2 |
| Kiewit Corporation | Omaha, NE | 2 |
| Lhoist North America of Tennessee, LLC | Brentwood, TN | 2 |
| Benthic USA LLC | Houston, TX | 2 |
| Canary Systems, Inc. | New London, NH | 2 |
| Fpa Pacific Corp. | Tinian, | 2 |
| Ciner Enterprises Inc. | Atlanta, | 2 |
| Newcrest Resources, Inc. | Denver, CO | 2 |
| ECS Southeast, LLC | Chantilly, VA | 2 |
| Dynamic Compaction Solutions Inc | Loveland, CO | 2 |
| SNF Holding Company | Riceboro, GA | 2 |
| Nyrstar Tennessee Mines - Gordonsville, LLC | Gordonsville, TN | 2 |
| Jacobs Engineering Group Inc. | Houston, TX | 2 |
| Concordia Wireless, Inc. | Carol Stream, IL | 2 |
| OYO Corporation, Pacific | Tamuning, | 2 |
| SSR Mining Inc. | Denver, CO | 2 |
| GZA GeoEnvironmental, Inc. | Norwood, MA | 1 |
| Mammoth Minerals Nevada, LLC | Reno, NV | 1 |
| DREAM Venture Labs Inc. | Cambridge, MA | 1 |
| OYO Corporation, Pacific | Tumon, | 1 |
| Golden Vertex Corp | Bullhead City, AZ | 1 |
| Navajo Transitional Energy Company, LLC | Farmington, NM | 1 |
| Point72 Asset Management, L.P. | Stamford, CT | 1 |
| AspenTech Corporation | Bedford, MA | 1 |
| Lhoist North America of Arizona, Inc. | Fort Worth, TX | 1 |
| Iron Oak Management LLC | The Woodlands, TX | 1 |
| Tierra South Florida, Inc. | West Palm Beach, FL | 1 |
| Pesado Construction Company | San Antonio, TX | 1 |
| University Of Kentucky | Lexington, KY | 1 |
| U.S. Silver - Idaho, Inc. | Wallace, ID | 1 |
| KRJA Systems Inc. | Golden, CO | 1 |
| Argos USA, LLC | Alpharetta, GA | 1 |
| Fugro USA Land, Inc. | Houston, TX | 1 |
| Braun Intertec Corporation | Minneapolis, MN | 1 |
| Milford Mining Company Utah LLC | Milford, UT | 1 |
| AB Consultants, Inc. | Lanham, MD | 1 |
| Stillwater Mining Company | Columbus, MT | 1 |
| Barnard Construction Company Inc. | Bozeman, MT | 1 |
| MineraLogic LLC | Duluth, MN | 1 |
| Anderson Professional Services, LLC. | Nicholasville, KY | 1 |
| Hatch Associates Consultants, Inc. | Pittsburgh, PA | 1 |
| Kennecott Exploration Company | Salt Lake City, UT | 1 |
| Chevron USA Inc. | Houston, TX | 1 |
| Agnico Eagle USA Limited | Reno, NV | 1 |
| ECS Midwest, LLC | Chantilly, VA | 1 |
| South Dakota State University | Brookings, SD | 1 |
| NXP USA, Inc. | Austin, TX | 1 |
| Compass Minerals Ogden Inc. | Ogden, UT | 1 |
| Columbia River Carbonates | Woodland, WA | 1 |
| Aramco Services Company | Houston, TX | 1 |
| ECS Florida, LLC | Chantilly, VA | 1 |
| South32 Hermosa Inc. | Tucson, AZ | 1 |
| Ramboll Americas Engineering Solutions, Inc. | Syracuse, NY | 1 |
| Usibelli Coal Mine, Inc. | Healy, AK | 1 |
| Albemarle Corporation | Charlotte, NC | 1 |
| Freeport-McMoRan Exploration Corporation | Phoenix, AZ | 1 |
| Nyrstar Clarksville, Inc. | Clarksville, TN | 1 |
| Bendito Resources USA Inc. | Reno, NV | 1 |
| Lisbon Valley Mining Co. LLC | Moab, UT | 1 |
| Hydrostor USA Holdings Inc. | Denver, CO | 1 |
| National Cement Company of California, Inc. | Encino, CA | 1 |
| CertainTeed Gypsum Manufacturing, Inc. | Malvern, PA | 1 |
| Southlands Engineering, LLC | Tucson, AZ | 1 |
| Wilkinson Stekloff LLP | Washington, DC | 1 |
| Millcreek Capital Management LLC | Cedar Creek, TX | 1 |
| J.R. Simplot Company | Boise, ID | 1 |
| Omya Inc. | Cincinnati, | 1 |
| Resolve Mining Consultants LLC | Sheridan, WY | 1 |
| Mako US Corp | Tuscon, AZ | 1 |
| McEwen Mining Inc. | Elko, NV | 1 |
| Austin Elements Inc | Houston, TX | 1 |
| Copper World, Inc | Tucson, AZ | 1 |
| Resource International, Inc | Columbus, OH | 1 |
| AngloGold Ashanti North America Inc. | Greenwood Village, CO | 1 |
| Mining & Environmental Services LLC | Sandy, UT | 1 |
| Rockhead LLC | Tie Siding, WY | 1 |
| Geocal | Centennial, CO | 1 |
| Kiewit-Shea Constructors, A Joint Venture | Omaha, NE | 1 |
| Tilcon New York Inc. | Parsippany, NJ | 1 |
| Jervois Mining USA, Limited | Salmon, ID | 1 |
| Omya Inc. | Mason, OH | 1 |
| Salado Isolation Mining Contractors, LLC | Carlsbad, NM | 1 |
| Mining Plus US Corporation | Las Vegas, NV | 1 |
| Cemvita Factory Inc. | Houston, TX | 1 |
| GMS Mine Repair & Maintenance Inc | Mt Lake Park, MD | 1 |
| Layne Minerals, LLC | Chandler, AZ | 1 |
| Harper Mining LLC | Peoria, IL | 1 |
| Planck Holdings LLC | Beckley, | 1 |
| Klondex Gold and Silver Mining Company | Winnemucca, | 1 |
| Snf Holding Company | Riceboro, | 1 |
| Newmont Cripple Creek Victor Mining Company | Denver, | 1 |
| Climax Molybdenum Company | Fort Madison, | 1 |
| Datamine North America, Inc. | Denver, | 1 |
| Intrepid Potash, Inc. | Denver, CO | 1 |
| Blue Copper Resources Corp. | Golden, CO | 1 |
| Ash Grove Cement Company | Overland Park, KS | 1 |
| Guideline Geo Americas, Inc | Summerville, SC | 1 |
| GS Mining Company, LLC | West Hollywood, CA | 1 |
| Broken Hill Proprietary (USA), Inc. | Tucson, AZ | 1 |
| International Directional Services, LLC | Chandler, AZ | 1 |
| Thiess Mining USA Inc. | Salt Lake City, UT | 1 |