WARRANT CERTIFICATE GASTAR EXPLORATION LTD. (A Corporation subsisting under the laws of the Province of Alberta)

EXHIBIT 4.12

UNLESS PERMITTED UNDER SECURITIES LEGISLATION, THE HOLDER OF THIS PURCHASE WARRANT CERTIFICATE MUST NOT TRADE THE PURCHASE WARRANTS OR THE COMMON SHARES ISSUABLE UPON EXERCISE BEFORE OCTOBER 24, 2004.

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES LAWS AND NEITHER THE SECURITIES NOR ANY INTEREST THEREIN MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN EFECTIVE REGISTRATION UNDER SUCH ACT OR AN EXEMPTION FROM REGISTRATION, WHICH, IN THE OPINION OF COUNSEL REASONABLE SATISFACTORY TO COUNSEL FOR THIS CORPORATION, IS AVAILABLE.

THE PURCHASE WARRANT REPRESENTED BY THIS CERTIFICATE WILL BE VOID AND OF NO VALUE UNLESS EXERCISED NO LATER THAN 4:30 p.m. (TORONTO TIME) ON JUNE 24, 2009.

WARRANT CERTIFICATE

GASTAR EXPLORATION LTD.

(A Corporation subsisting under the laws of the Province of Alberta)

THIS IS TO CERTIFY THAT Ingalls & Snyder Value Partners L.P. (hereinafter referred to as the “holder”) is the registered holder of that number of Purchase Warrants to acquire Common Shares (as hereinafter defined) of Gastar Exploration Ltd. (the “Corporation”) as set forth in this Purchase Warrant certificate (“Warrant Certificate”). Each Purchase Warrant represented hereby entitles the holder thereof to acquire, in the manner and subject to the restrictions and adjustments set forth herein, at any time and from time to time until 4:30 p.m. (Toronto Time) (the “Time of Expiry”) on June 24, 2009 (the “Expiry Date”), one (1) fully paid and non-assessable common share without nominal or par value, (together with any other securities which may be issued or distributed by the Corporation with respect thereto or in substitution therefore, the “Common Shares”) of the Corporation, at a price of US$3.23 per share.

The right to acquire Common Shares hereunder may only be exercised by the holder within the time set forth above by:

These Purchase Warrants may be surrendered only upon personal delivery hereof or, if sent by mail or other means of transmission, upon actual receipt thereof by the Corporation at the office referred to above.

Upon exercise of these Purchase Warrants as provided above, the person or persons in whose name or names the Common Shares issuable upon exercise of the Purchase Warrants are to be issued shall be deemed for all purposes to be the holder or holders of record of such Common Shares and the Corporation will cause a certificate or certificates representing such Common Shares to be delivered or mailed to the person or persons at the address or addresses specified in the Exercise Form within twenty (20) Business Days.

The registered holder of this Warrant Certificate may acquire any lesser number of Common Shares than the number of Common Shares which may be acquired for the Purchase Warrants represented by this Warrant Certificate. In such event, the holder shall be entitled to receive a new certificate for the balance of the Common Shares which may be acquired. To the extent that the holder is entitled to receive on the exercise or partial exercise thereof a fraction

of a Common Share, such right may only be exercised in respect of such fraction in combination with another Purchase Warrant or other Purchase Warrants, which in the aggregate entitles the holder to receive a whole number of Common Shares.

If the holder is not able to or elects not to, combine Purchase Warrants so as to be entitled to acquire a whole number of Common Shares, the Corporation shall make an appropriate cash settlement. However, in respect of any holder, the Corporation shall only be required to make such a cash adjustment once and for one Purchase Warrant and no more. The amount of the cash adjustment with respect to the Common Share shall be equal to the fraction of the Common Share to which the holder would be entitled multiplied by the current market price of the Common Shares as determined in good faith by the Corporation.

The Corporation agrees that, prior to the expiration of this Purchase Warrant, the Corporation will at all times:

a. have authorized and in reserve, and will keep available, solely for issuance or delivery upon the exercise of this Purchase Warrant, the maximum amount of shares of Common Shares and other securities and properties as from time to time shall be receivable upon the exercise of this Purchase Warrant, free and clear of all restrictions on sale or transfer, except for

b. cause the Common Shares to be listed on the Toronto Stock Exchange or other securities exchange on which the Common Shares are then listed.

The Corporation covenants that:

a. all of the Common Shares are validly authorized and, if and when this Purchase Warrant is exercised in whole or in part in accordance with the terms hereof, the Common Shares issued upon such exercise, upon receipt by the Corporation of the full per share warrant price therefor, shall be validly issued, fully paid, nonassessable, and will not be issued in violation of any preemptive rights or other rights of stockholders;

b. it will pay, when due and payable, any and all federal, provincial and state stamp, original issue or similar taxes which may be payable in respect of any Common Shares or any certificate thereof to the exercise of the Purchase Warrants; and

c. it will comply with all filings and reporting obligations required to maintain good standing with the Toronto Stock Exchange or such other stock exchange as the Common Shares may then be listed upon, and thereby maintain its Common shares so listed.

In the event of any alteration of the Common Shares, including any subdivision, consolidation or reclassification, and in the event of any form of reorganization of the Corporation including any amalgamation, merger or arrangement, or any dividend or distribution of Common Shares or other securities or property, or successive transactions thereof, the holders of Purchase Warrants shall, upon exercise of the Purchase Warrants following the occurrence of any of those events, be entitled to receive had they exercised their Purchase Warrants immediately prior to the occurrence of those events. The Corporation covenants to take such steps as may be necessary to ensure that the issuer of any shares of stock or other securities or property thereafter deliverable on the exercise of this Purchase Warrant, pursuant to any of the alterations described above, shall be responsible for all of the agreements and obligations of the Corporation hereunder, and the Corporation shall ensure that such issuer executes an agreement with the holder providing that the holder has the rights thereafter to receive upon exercise of this Purchase Warrant such shares, security or property. In case at any time the Corporation shall take any action requiring an adjustment as described above, the Corporation shall give written notice thereof, to the holder at the holder’s address as it shall appear on the books of the Corporation, at least fifteen (15) days prior to the date as of which the holders of record of the Common Shares are entitled to receive any shares, securities or property.

The holding of the Purchase Warrants evidenced by this Warrant Certificate shall not constitute the holder hereof a shareholder of the Corporation or entitle the holder to any right or interest in respect thereof except as expressly provided in this Warrant Certificate.

The Purchase Warrants evidenced by this Warrant Certificate may be transferred on the register kept at the principal offices of the Corporation at its principal offices in Mt. Pleasant, Michigan by the registered holder hereof or its legal representatives or its attorney duly appointed by an instrument in writing in form and execution satisfactory to the Corporation.

Exercise by a U.S. Person or within the United States of this Purchase Warrant will be subject to the recipient of the Common Shares to be issued upon such exercise being an “Accredited Investor” within the meaning of Rule 501 under the Securities Act of 1933, as amended, as determined in good faith by the Corporation.

This Warrant Certificate shall not be valid for any purpose whatever unless and until it has been signed by or on behalf of the Corporation.

Upon receipt of evidence satisfactory to the Corporation of the loss, theft, destruction or mutilation of this Purchase Warrant, and upon receipt of indemnity reasonably satisfactory to the Corporation, if lost, stolen or destroyed, and upon surrender and cancellation of this Purchase Warrant, if mutilated, the Corporation shall execute and deliver to the holder a new Purchase Warrant of like date, tenor and denomination.

The parties hereto irrevocably consent to the exclusive jurisdiction of the courts of the Province of Alberta in connection with any action or proceeding arising out of or relating to this Purchase Warrant, any document or instrument delivered pursuant to, in connection with or simultaneously with this Purchase Warrant, or a breach of this Purchase Warrant or any such document or instrument. In any such action or proceeding, each party hereto waives personal service of any summons, complaint or other process and agrees that service thereof may be made to the respective agents of the parties designated to receive service of process. Within thirty (30) days after such service, or such other time as may be mutually agreed upon in writing by the attorneys for the parties to such action or proceeding, the party so served shall appear or answer such summons, complaint or other process.

No course of dealing and no delay or omission on the part of the holder in exercising any right or remedy shall operate as a waiver thereof or otherwise prejudice the holder’s rights, powers or remedies. No right, power or remedy conferred by this Purchase Warrant upon the holder shall be exclusive of any other right, power or remedy referred to herein or now or hereafter available at law, in equity, by statute or otherwise, and all such remedies may be exercised singly or concurrently.

This Purchase Warrant may be amended only by a written instrument executed by the Corporation and the holder hereof. Any amendment shall be endorsed upon this Purchase Warrant, and all future holders shall be bound thereby.

Time shall be of the essence hereof. This Warrant Certificate shall be governed by and construed in accordance with the laws of the Province of Alberta and the federal law applicable therein and shall be treated in all respects as an Alberta contract.

IN WITNESS WHEREOF the Corporation has caused this Warrant Certificate to be signed by its duly authorized officers as of June 24, 2004.

TRANSFER OF PURCHASE WARRANTS

FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers to                                                      ,                          Purchase Warrants of Gastar Exploration Ltd. (the “Corporation”) registered in the name of the undersigned on the records of the Corporation represented by the Warrant Certificate attached and irrevocably appoints                          the attorney of the undersigned to transfer the said securities on the books or register with full power of substitution.

If less than all the Purchase Warrants represented by this Warrant Certificate are being transferred, the Warrant Certificate representing those Purchase Warrants not transferred will be registered in the name appearing on the face of this Warrant Certificate and such certificates (please check one):

DATED the      day of                     ,         .

Instructions:

EXERCISE FORM

(a) The undersigned hereby exercises the right to acquire                              Common Shares of Gastar Exploration Ltd..

(b) The Common Shares (or other securities or property) are to be issued as follows:

Note: If further nominees intended, please attach (and initial) schedule giving these particulars.

(c) Such securities (please check one):

OR

If the number of Purchase Warrants exercised are less than the number of Purchase Warrants represented hereby, the undersigned requests that the new Warrant Certificate representing the balance of the Purchase Warrants be registered in the name of

Such securities (please check one):

OR

In the absence of instructions to the contrary, the securities or other property will be issued in the name of or to the holder hereof and will be sent by first class mail to the last address of the holder appearing on the register maintained for the Purchase Warrants.

DATED this              day of                 ,         .

Instructions: