UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

U.S. Silica Holdings, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

90346E103

(CUSIP Number)

December 31, 2018

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed.

☐ Rule 13d-1(b)

☒ Rule 13d-1(c)

☐ Rule 13d-1(d)

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

U.S. Silica Holdings, Inc.

24275 Katy Freeway

Suite 100

Katy, TX 77494

United States

This statement is filed by: (i) Caselton Investments LLC (“Caselton”) with respect to its beneficially owned shares of common stock (“Shares”) of the Issuer; (ii) Ricardo J. Cisneros, who, through his indirect ownership of 100% of the issued and outstanding equity interests in Caselton, may be deemed a beneficial owner with respect to Shares of the Issuer beneficially owned by Caselton; and (iii) Eduardo Cisneros with respect to Shares of the Issuer beneficially owned as an individual and with respect to Shares of the Issuer beneficially owned by Caselton for which Eduardo Cisneros, in his capacity as President of Caselton, may be deemed a beneficial owner.

The mailing address of Caselton Investments LLC, Ricardo J. Cisneros and Eduardo Cisneros is 2020 Ponce de Leon Blvd., PH-2, Coral Gables, Florida 33134.

Caselton is a Delaware limited liability company.

Ricardo J. Cisneros is a citizen of Spain.

Eduardo Cisneros is a citizen of Colombia.

Common Stock

90346El03

Not applicable

The percentages used herein are calculated based upon the 77,511,268 shares of common stock outstanding as September 30, 2018, as reported on the Issuer’s quarterly report on Form 10-Q filed with the Securities and Exchange Commission by the Issuer for the quarterly period ended September 30, 2018.

As of the close of business on December 31, 2018:

1. Caselton Investments LLC

(a) Amount beneficially owned: 3,227,754

(b) Percent of class: 4.16%

(c)(i) Sole power to vote or direct the vote: -0-

(ii) Shared power to vote or direct the vote: 3,227,754

(iii) Sole power to dispose or direct the disposition: -0-

(iv) Shared power to dispose or direct the disposition: 3,227,754

2. Ricardo J. Cisneros

(a) Amount beneficially owned: 3,227,754

(b) Percent of class: 4.16%

(c)(i) Sole power to vote or direct the vote: -0-

(ii) Shared power to vote or direct the vote: 3,227,754

(iii) Sole power to dispose or direct the disposition: -0-

(iv) Shared power to dispose or direct the disposition: 3,227,754

3. Eduardo Cisneros

(a) Amount beneficially owned: 3,313,754

(b) Percent of class: 4.28%

(c)(i) Sole power to vote or direct the vote: 86,000

(ii) Shared power to vote or direct the vote: 3,227,754

(iii) Sole power to dispose or direct the disposition: 86,000

(iv) Shared power to dispose or direct the disposition: 3,227,754

If this Statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.  ☒

Not applicable.

Not applicable.

Caselton Investments LLC.

Ricardo J. Cisneros.

Eduardo Cisneros.

Not applicable

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

JOINT FILING AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of shares of common stock of U.S. Silica Holdings, Inc.