EX-10.21



 Exhibit 10.21 

JOINDER AGREEMENT 

THIS JOINDER AGREEMENT (this “Agreement”), dated as of March 31, 2015 (the “Joinder Date”), by and
among (i) PNC BANK, NATIONAL ASSOCIATION (“PNC”), in its capacity as agent for the Lenders under the Credit Agreement (as hereinafter defined) (PNC, together with its successors and assigns in such capacity, the
“Agent”), (ii) MAMMOTH ENERGY PARTNERS LP, a limited partnership under the laws of the State of Delaware (“Mammoth”), REDBACK ENERGY SERVICES LLC, a limited liability company under the laws of the State of
Delaware (“Redback Energy”), REDBACK COIL TUBING LLC, a limited liability company under the laws of the State of Delaware (“Redback Coil”), MUSKIE PROPPANT LLC, a limited liability company under the laws of the
State of Delaware (“Muskie”), PANTHER DRILLING SYSTEMS LLC, a limited liability company under the laws of the State of Delaware (“Panther”), BISON DRILLING AND FIELD SERVICES LLC, a limited liability company under
the laws of the State of Delaware (“Bison Drilling”), BISON TRUCKING LLC, a limited liability company under the laws of the State of Delaware (“Bison Trucking”), WHITE WING TUBULAR SERVICES LLC, a limited liability
company under the laws of the State of Delaware (“White Wing”), GREAT WHITE SAND TIGER LODGING LTD., a Canadian limited company (“Sand Tiger”), STINGRAY PRESSURE PUMPING LLC, a limited liability company under the
laws of the State of Delaware (“Stingray Pressure”), STINGRAY LOGISTICS LLC, a limited liability company under the laws of the State of Delaware (“Stingray Logistics”; and together with Mammoth, Redback Energy,
Redback Coil, Muskie, Panther, Bison Drilling, Bison Trucking, White Wing, Sand Tiger, Stingray Pressure, individually, each an “Existing Borrowers” and together, collectively, the “Existing Borrowers”) and
(iii) MAMMOTH ENERGY INC., a corporation organized under the laws of the State of Delaware, and BARRACUDA LOGISTICS LLC, a limited liability company organized under the laws of the State of Delaware (individually, each an
“Applicant” and together, collectively, the “Applicants”). 
 WHEREAS, Existing Borrowers, Agent
and each of the financial institutions from time to time party thereto (collectively, the “Lenders”) are parties to that certain Revolving Credit and Security Agreement, dated as of November 25, 2014 (as heretofore and may
hereafter be amended, amended and restated, joined, extended, supplemented and/or otherwise modified from time to time, the “Credit Agreement”). Capitalized terms used herein but not defined herein shall have the meanings
ascribed to them in the Credit Agreement. 
 WHEREAS, each Applicant desires to become a “Borrower” pursuant to the terms
of the Credit Agreement. 
 NOW THEREFORE, the Applicants, together with the Existing Borrowers hereby agree, jointly and severally
with the Agent and Lenders as follows: 
 A.    Each Applicant hereby acknowledges, agrees and confirms that, as of the
date hereof and as if it had executed the Credit Agreement and the Other Documents, it shall be and shall have all of the obligations of a Borrower (as defined in the Credit Agreement) set forth in the Credit Agreement and shall be a party of
identical capacity and obligations as a Borrower to the Credit Agreement and each of the Other Documents. As of the date hereof, each Applicant hereby ratifies and agrees to be bound by all of the terms, provisions and conditions contained in








 
the Credit Agreement and the Other Documents that are binding upon Borrowers, including, without limitation (a) all of the representations and warranties of Borrowers set forth in
Article V of the Credit Agreement, as supplemented from time to time in accordance with the terms thereof, and (b) all of the covenants set forth in Articles VI and VII of the Credit Agreement (and as to
these clauses (a) and (b) giving due account to the date of such Applicant’s formation). 
 B.    Without
limiting the generality of the foregoing provisions, each Applicant hereby grants to Agent, for the benefit of the Lenders, as of the date hereof and as security for the Obligations, a continuing first priority security interest in and Lien upon,
and pledges to Agent, all of its right, title and interest in, to and upon all of the Applicant’s assets, now owned or hereafter acquired, including the Collateral of such Applicant, pursuant to the terms a provisions as set forth in
Article IV of the Credit Agreement and in each Other Document. 
 C.    Each Applicant
acknowledges and confirms that it has received a copy of the Credit Agreement and the exhibits, schedules and other attachments thereto and the Other Documents. The Schedules to the Credit Agreement are amended to include the information
relating to Applicant set forth on the attached Exhibit A. 
 D.    Existing Borrowers confirm
that all of their obligations under the Credit Agreement and the Other Documents are, and upon each Applicant becoming a “Borrower” thereunder or otherwise party thereto pursuant to the terms hereof, shall continue to be, in full force and
effect. 
 E.    Existing Borrowers further confirm that, as of the date hereof, the term “Obligations”, as
used in the Credit Agreement, shall include all Obligations of the Applicants under the Credit Agreement and each Other Document. This Agreement shall be an Other Document for all purposes. 

F.    Existing Borrowers and the Applicants agree that at any time and from time to time, upon the written request of
Agent, they will execute and deliver such further documents and do such further acts and things as the Agent or the Lenders may reasonably request in order to effect the purposes of this Agreement. 

G.    This Agreement may be executed in one or more counterparts (which taken together, as applicable, shall constitute
one and the same instrument) and by facsimile transmission, which facsimile signatures shall be considered original executed counterparts. Each party to this Agreement agrees that it will be bound by its own facsimile signature and that it accepts
the facsimile signature of each other party. 
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 IN WITNESS WHEREOF, the Applicants, Existing Borrowers, Agent and the Lenders have caused this
Agreement to be duly executed and delivered by its authorized officer as of the day and year first above written. 
  

 

			
	APPLICANTS:
	
	MAMMOTH ENERGY INC.
		
	By:	 	 /s/Marc McCarthy

	Name:	 	Marc McCarthy
	Title:	 	Chairman
	
	BARRACUDA LOGISTICS LLC
		
	By:	 	 /s/ Arthur Amron

	Name:	 	Arthur Amron
	Title:	 	Vice President and Assistant Secretary


 [Signature Page to Joinder Agreement] 







 
			
	EXISTING BORROWERS:
	
	MAMMOTH ENERGY PARTNERS LP
		
	By:	 	 /s/ Arthur Amron

	Name:	 	Arthur Amron
	Title:	 	Vice President and Assistant Secretary
	
	 BISON DRILLING AND FIELD SERVICES LLC

	BISON TRUCKING LLC
	GREAT WHITE SAND TIGER LODGING LTD.
	MUSKIE PROPPANT LLC
	PANTHER DRILLING SYSTEMS LLC
	REDBACK COIL TUBING LLC
	REDBACK ENERGY SERVICES LLC
	STINGRAY LOGISTICS LLC
	STINGRAY PRESSURE PUMPING LLC
	WHITE WING TUBULAR SERVICES LLC
		
	By.	 	 /s/ Arthur Amron

	Name:	 	Arthur Amron
	Title:	 	Vice President and Assistant Secretary


 [Signature Page to Joinder Agreement] 







 
			
	AGENT:
	
	PNC BANK, NATIONAL ASSOCIATION
		
	By:	 	 /s/ Ronald Eckhoff

	Name:	 	Ronald Eckhoff
	Title:	 	Vice President


 [Signature Page to Joinder Agreement] 







 EXHIBIT A 

(See attached) 







 Schedule 5.2(b) 

Subsidiaries 
  

					
	 Subsidiary
	 	 Equity Interests
	 	 Beneficial Owners of Capital Stock

	Mammoth Energy Partners LP	 	Limited Partnership Interests	 	 •    Mammoth Energy Holdings LLC

•    Gulfport Energy Corporation

•    Rhino Exploration LLC

•    Mammoth Energy Partners GP LLC (Non-economic, GP interests)

			
	Redback Energy Services LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Redback Coil Tubing LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Muskie Proppant LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Panther Drilling Systems LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Bison Drilling and Field Services LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Bison Trucking LLC	 	Membership Interests	 	 •    Bison Drilling and Field Services LLC

			
	White Wing Tubular Services LLC	 	Membership Interests	 	 •    Bison Drilling and Field Services LLC

			
	Stingray Pressure Pumping LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Stingray Logistics LLC	 	Membership Interests	 	 •    Mammoth Energy Partners LP

			
	Sand Tiger Holdings Inc.	 	Common Stock	 	 •    Mammoth Energy Partners LP

			
	Great White Sand Tiger Lodging Ltd.	 	Shares	 	 •    Sand Tiger Holdings Inc.

			
	Mammoth Energy Inc.	 	Common Stock	 	 •    Mammoth Energy Partners LP

			
	Barracuda Logistics LLC	 	Membership Interests	 	 •    Stingray Pressure Pumping LLC