# EDGAR Filing Document

**Accession Number:** 0001697500
**File Stem:** 0001140361-23-006741
**Filing Date:** 2023-2
**Character Count:** 24848
**Document Hash:** 26f31a487db74550ed0f105cb5965387
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-23-006741.hdr.sgml**: 20230214

**ACCESSION NUMBER**: 0001140361-23-006741

**CONFORMED SUBMISSION TYPE**: SC 13G/A

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20230214

**DATE AS OF CHANGE**: 20230214

**GROUP MEMBERS**: YORKTOWN X ASSOCIATES LLC

**GROUP MEMBERS**: YORKTOWN X CO LP

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Solaris Oilfield Infrastructure, Inc.
- **CENTRAL INDEX KEY:** 0001697500
- **STANDARD INDUSTRIAL CLASSIFICATION:** OIL & GAS FILED MACHINERY & EQUIPMENT [3533]
- **IRS NUMBER:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC 13G/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-89983
- **FILM NUMBER:** 23625306

**BUSINESS ADDRESS:**
- **STREET 1:** 9811 KATY FREEWAY
- **STREET 2:** SUITE 700
- **CITY:** HOUSTON
- **STATE:** TX
- **ZIP:** 77024
- **BUSINESS PHONE:** (281)501-3070

**MAIL ADDRESS:**
- **STREET 1:** 9811 KATY FREEWAY
- **STREET 2:** SUITE 700
- **CITY:** HOUSTON
- **STATE:** TX
- **ZIP:** 77024
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Yorktown Energy Partners X, L.P.
- **CENTRAL INDEX KEY:** 0001577919
- **IRS NUMBER:** 462445852
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC 13G/A

**BUSINESS ADDRESS:**
- **STREET 1:** 410 PARK AVENUE
- **STREET 2:** 20TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** 212-515-2115

**MAIL ADDRESS:**
- **STREET 1:** 410 PARK AVENUE
- **STREET 2:** 20TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022

------

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

### Schedule 13G

#### Under the Securities Exchange Act of 1934

#### (Amendment No. 2)\*

## Solaris Oilfield Infrastructure, Inc.

#### (Name of Issuer)

#### Class A common stock, par value $0.01 per share

#### (Title of Class of Securities)

#### 83418M103
(**CUSIP Number)**

#### March 10, 2021

#### (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) <br> ☐ Rule 13d-1(c) <br> ☒ Rule 13d-1(d)

\*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required on 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).

------

---

| | | |
|:---|:---|:---|
| CUSIP No. 83418M103 | CUSIP No. 83418M103 | CUSIP No. 83418M103 |
| **1** | **NAMES OF REPORTING PERSONS** | **NAMES OF REPORTING PERSONS** |
| **1** | YORKTOWN ENERGY PARTNERS X, L.P. | YORKTOWN ENERGY PARTNERS X, L.P. |
| **1** | YORKTOWN ENERGY PARTNERS X, L.P. | YORKTOWN ENERGY PARTNERS X, L.P. |
| **2** | **CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP** | **CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP** |
| **2** | (a)☐ | (a)☐ |
| **2** | (b)☐ | (b)☐ |
| **3** | **SEC USE ONLY** | **SEC USE ONLY** |
| **3** |  |  |
| **3** |  |  |
| **4** | **CITIZENSHIP OR PLACE OF ORGANIZATION** | **CITIZENSHIP OR PLACE OF ORGANIZATION** |
| **4** | Delaware | Delaware |
| **4** | Delaware | Delaware |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | **SOLE VOTING POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | 8054234 (1) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | 8054234 (1) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | **SHARED VOTING POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | **SOLE DISPOSITIVE POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | 8054234(1) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | 8054234(1) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | **SHARED DISPOSITIVE POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | 0 |
| **9** | **AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON** | **AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON** |
| **9** | 8,054,234 of Class A common stock (1) | 8,054,234 of Class A common stock (1) |
| **9** | 8,054,234 of Class A common stock (1) | 8,054,234 of Class A common stock (1) |
| **10** | **CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)** | **CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)** |
| **10** | ☐ | ☐ |
| **10** | ☐ | ☐ |
| **11** | **PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)** | **PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)** |
| **11** | 19.65% (2) | 19.65% (2) |
| **11** | 19.65% (2) | 19.65% (2) |
| **12** | **TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)** | **TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)** |
| **12** | PN | PN |
| **12** | PN | PN |

---

(1) Beneficial ownership of the Class A common stock, par value $0.01 per share ("**Class A Common Stock**"), of Solaris Oilfield Infrastructure, Inc. (the "**Issuer**") referred to herein is being reported hereunder solely because the reporting person directly owns 8,054,234 shares of Class B common stock of the Issuer ("**Class B Common Stock**") and 8,054,234 membership interests ("**Solaris LLC Units**") in Solaris Oilfield Infrastructure, LLC ("**Solaris LLC**"), which are exchangeable for shares of Class A Common Stock on a one-for-one basis, pursuant to the Second Amended and Restated Limited Liability Company Agreement of Solaris LLC (the "**Solaris LLC Agreement**"). Neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission by any reporting person that it is the beneficial owner of any of the securities referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or for any other purpose, and such beneficial ownership is expressly disclaimed.

(2) Based on 32,934,930 shares of Class A Common Stock of the Issuer issued and outstanding as of October 27, 2022 as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "**SEC**") on November 2, 2022 (the "**10-Q**") and 8,054,234 shares of Class A Common Stock issuable upon the exchange of shares of Class B Common Stock together with Solaris LLC Units as described above.

------

---

| | | |
|:---|:---|:---|
| CUSIP No. 83418M103 | CUSIP No. 83418M103 | CUSIP No. 83418M103 |
| **1** | **NAMES OF REPORTING PERSONS** | **NAMES OF REPORTING PERSONS** |
| **1** | YORKTOWN X COMPANY LP | YORKTOWN X COMPANY LP |
| **1** | YORKTOWN X COMPANY LP | YORKTOWN X COMPANY LP |
| **2** | **CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP** | **CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP** |
| **2** | (a)☐ | (a)☐ |
| **2** | (b)☐ | (b)☐ |
| **3** | **SEC USE ONLY** | **SEC USE ONLY** |
| **3** |  |  |
| **3** |  |  |
| **4** | **CITIZENSHIP OR PLACE OF ORGANIZATION** | **CITIZENSHIP OR PLACE OF ORGANIZATION** |
| **4** | Delaware | Delaware |
| **4** | Delaware | Delaware |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | **SOLE VOTING POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | **SHARED VOTING POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | **SOLE DISPOSITIVE POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | **SHARED DISPOSITIVE POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | 0 |
| **9** | **AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON** | **AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON** |
| **9** | 8,054,234 of Class A common stock (1)(2) | 8,054,234 of Class A common stock (1)(2) |
| **9** | 8,054,234 of Class A common stock (1)(2) | 8,054,234 of Class A common stock (1)(2) |
| **10** | **CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)** | **CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)** |
| **10** | ☐ | ☐ |
| **10** | ☐ | ☐ |
| **11** | **PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)** | **PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)** |
| **11** | 19.65% (3) | 19.65% (3) |
| **11** | 19.65% (3) | 19.65% (3) |
| **12** | **TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)** | **TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)** |
| **12** | PN | PN |
| **12** | PN | PN |

---

(1) Beneficial ownership of the Class A Common Stock of the Issuer referred to herein is being reported hereunder solely because the reporting person may be deemed to beneficially own 8,054,234 shares of Class B Common Stock and 8,054,234 Solaris LLC Units, which are exchangeable for shares of Class A Common Stock on a one-for-one basis, pursuant to the Solaris LLC Agreement. Neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission by any reporting person that it is the beneficial owner of any of the securities referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or for any other purpose, and such beneficial ownership is expressly disclaimed.

(2) These securities are directly held by Yorktown Energy Partners X, L.P., a Delaware limited partnership ("**Yorktown X**"). Yorktown X Company LP, a Delaware limited partnership ("**Yorktown X Company**"), is the sole general partner of Yorktown X. As a result, Yorktown X Company may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown X. Yorktown X Company disclaims beneficial ownership of the securities owned by Yorktown X in excess of its pecuniary interests therein.

(3) Based on 32,934,930 shares of Class A Common Stock of the Issuer issued and outstanding as of October 27, 2022 as reported in the 10-Q and 8,054,234 shares of Class A Common Stock issuable upon the exchange of shares of Class B Common Stock together with Solaris LLC Units as described above.

------

---

| | | |
|:---|:---|:---|
| CUSIP No. 83418M103 | CUSIP No. 83418M103 | CUSIP No. 83418M103 |
| **1** | **NAMES OF REPORTING PERSONS** | **NAMES OF REPORTING PERSONS** |
| **1** | YORKTOWN X ASSOCIATES LLC | YORKTOWN X ASSOCIATES LLC |
| **1** | YORKTOWN X ASSOCIATES LLC | YORKTOWN X ASSOCIATES LLC |
| **2** | **CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP** | **CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP** |
| **2** | (a)☐ | (a)☐ |
| **2** | (b)☐ | (b)☐ |
| **3** | **SEC USE ONLY** | **SEC USE ONLY** |
| **3** |  |  |
| **3** |  |  |
| **4** | **CITIZENSHIP OR PLACE OF ORGANIZATION** | **CITIZENSHIP OR PLACE OF ORGANIZATION** |
| **4** | Delaware | Delaware |
| **4** | Delaware | Delaware |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | **SOLE VOTING POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **5** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | **SHARED VOTING POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **6** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | **SOLE DISPOSITIVE POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **7** | 8054234(1)(2) |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | **SHARED DISPOSITIVE POWER** |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | 0 |
| **NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH** | **8** | 0 |
| **9** | **AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON** | **AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON** |
| **9** | 8,054,234 of Class A common stock (1)(2) | 8,054,234 of Class A common stock (1)(2) |
| **9** | 8,054,234 of Class A common stock (1)(2) | 8,054,234 of Class A common stock (1)(2) |
| **10** | **CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)** | **CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)** |
| **10** | ☐ | ☐ |
| **10** | ☐ | ☐ |
| **11** | **PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)** | **PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)** |
| **11** | 19.65% (3) | 19.65% (3) |
| **11** | 19.65% (3) | 19.65% (3) |
| **12** | **TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)** | **TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)** |
| **12** | OO | OO |
| **12** | OO | OO |

---

(1) Beneficial ownership of the Class A Common Stock of the Issuer referred to herein is being reported hereunder solely because the reporting person may be deemed to beneficially own 8,054,234 shares of Class B Common Stock and 8,054,234 Solaris LLC Units, which are exchangeable for shares of Class A Common Stock on a one-for-one basis, pursuant to the Solaris LLC Agreement. Neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission by any reporting person that it is the beneficial owner of any of the securities referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or for any other purpose, and such beneficial ownership is expressly disclaimed.

(2) These securities are directly held by Yorktown X. Yorktown X Company is the sole general partner of Yorktown X and Yorktown X Associates LLC, a Delaware limited liability company ("**Yorktown X Associates**"), is the sole general partner of Yorktown X Company. As a result, Yorktown X Associates may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown X. Yorktown X Company and Yorktown X Associates disclaim beneficial ownership of the securities owned by Yorktown X in excess of their respective pecuniary interests therein.

(3) Based on 32,934,930 shares of Class A Common Stock of the Issuer issued and outstanding as of October 27, 2022 as reported in the 10-Q and 8,054,234 shares of Class A Common Stock issuable upon the exchange of shares of Class B Common Stock together with Solaris LLC Units as described above.

------

**Item 1(a).** **Name of Issuer:** Solaris Oilfield Infrastructure, Inc., a Delaware corporation (the "**Issuer**").

**Item 1(b). Address of Issuer's Principal Executive Offices:** 9811 Katy Freeway, Suite 700, Houston, Texas 77024.

**Item 2(a). Name of Person Filing:** This statement is jointly filed by Yorktown Energy Partners X, L.P., a Delaware limited partnership ("**Yorktown X**"), Yorktown X Company LP, a Delaware limited partnership and the general partner of Yorktown X ("**Yorktown X Company**"), and Yorktown X Associates LLC, a Delaware limited liability company and the general partner of Yorktown X Company ("**Yorktown X Associates**", and collectively, with Yorktown X and Yorktown X Company, the "**Reporting Persons**").

**Item 2(b). Address of Principal Business Office or, if None, Residence:** The principal business office address of Yorktown X, Yorktown X Company and Yorktown X Associates is 410 Park Avenue, 20th Floor, New York, New York 10022.

**Item 2(c). Citizenship:** Each of Yorktown X, Yorktown X Company and Yorktown X Associates is organized under the laws of the state of Delaware.

**Item 2(d). Title of Class of Securities:** Class A Common Stock of the Issuer.

**Item 2(e). CUSIP Number:** 83418M103

---

| | |
|:---|:---|
| **Item 3.** | **If this statement is filed pursuant to § 240.13d-1(b), or § 240.13d-2(b) or (c), check whether the person filing is a:** |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) ☐ Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) ☐ Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) ☐ Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) ☐ Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) ☐ An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) ☐ An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) ☐ A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h) ☐ A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) ☐ A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(j) ☐ A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(k) ☐ Group, in accordance with § 240.13d-1(b)(1)(ii)(K).

If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution: <u>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</u> <br>

------

---

| | |
|:---|:---|
| **Item 4.** | **Ownership.** |

---

The information regarding ownership set forth in Items 5-9 and 11 of each cover page is hereby incorporated herein by reference.

---

| | |
|:---|:---|
| **Item 5.** | **Ownership of Five Percent or Less of a Class.** |

---

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 5 percent of the class of securities, check the following ☐.

---

| | |
|:---|:---|
| **Item 6.** | **Ownership of More Than Five Percent on Behalf of Another Person.** |

---

Not applicable

---

| | |
|:---|:---|
| **Item 7.** | **Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.** |

---

Not applicable

---

| | |
|:---|:---|
| **Item 8.** | **Identification and Classification of Members of the Group.** |

---

Not applicable

---

| | |
|:---|:---|
| **Item 9.** | **Notice of Dissolution of Group.** |

---

Not applicable

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| | |
|:---|:---|
| **Item 10.** | **Certifications.** |

---

Not applicable.

------

SIGNATURE

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.

Date: February 14, 2023

---

| | |
|:---|:---|
| Yorktown Energy Partners X, L.P. | Yorktown Energy Partners X, L.P. |
| By: Yorktown X Company LP,  | By: Yorktown X Company LP,  |
| &nbsp;&nbsp;&nbsp; Its general partner | &nbsp;&nbsp;&nbsp; Its general partner |
| By: Yorktown X Associates LLC, | By: Yorktown X Associates LLC, |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner |
| By: | /s/ Robert A. Signorino |
| Name: | Robert A. Signorino |
| Title: | Manager |

---

---

| | |
|:---|:---|
| Yorktown X Company LP | Yorktown X Company LP |
| By: Yorktown X Associates LLC, | By: Yorktown X Associates LLC, |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner |
| By: | /s/ Robert A. Signorino |
| Name: | Robert A. Signorino |
| Title: | Manager |

---

---

| | |
|:---|:---|
| Yorktown X Associates LLC | Yorktown X Associates LLC |
| By: | /s/ Robert A. Signorino |
| Name: | Robert A. Signorino |
| Title: | Manager |

---

------

#### EXHIBIT INDEX

#### <br>
<u> Exhibit No. </u> <u> Description </u> <br>[1.1](ny20007533x1_ex1-1.htm) Joint Filing Agreement dated February 14, 2023.

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## Exhibit 1.1

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#### Exhibit 1.1

#### <br>

#### JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Class A common stock, par value $0.01 per share of SOLARIS OILFIELD INFRASTRUCTURE, INC., a Delaware corporation, and further agree that this Joint Filing Agreement be included as an exhibit to such joint filings. In evidence thereof, each of the undersigned hereby executes this Joint Filing Agreement as of February 14, 2023.

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| | |
|:---|:---|
| Yorktown Energy Partners X, L.P. | Yorktown Energy Partners X, L.P. |
| By: Yorktown X Company LP, | By: Yorktown X Company LP, |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner |
| By: Yorktown X Associates LLC, | By: Yorktown X Associates LLC, |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner |
| By: | /s/ Robert A. Signorino |
| Name: | Robert A. Signorino |
| Title: | Manager |
| Yorktown X Company LP | Yorktown X Company LP |
| By: Yorktown X Associates LLC, | By: Yorktown X Associates LLC, |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Its general partner |
| By: | /s/ Robert A. Signorino |
| Name: | Robert A. Signorino |
| Title: | Manager |
| Yorktown X Associates LLC | Yorktown X Associates LLC |
| By: | /s/ Robert A. Signorino |
| Name: | Robert A. Signorino |
| Title: | Manager |

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