FILING AGREEMENT DATED TO BE EFFECTIVE NOVEMBER 5, 2020 REGARDING JOINT FILING OF SCHEDULE 13D/A-12

EXHIBT A

FILING AGREEMENT DATED TO BE EFFECTIVE NOVEMBER 5, 2020

REGARDING JOINT FILING OF SCHEDULE 13D/A-12

The undersigned hereby agree that:

(i)Each is eligible to use the Schedule 13D/A-12 attached hereto; 

(ii)The attached Schedule 13D/A-12 is filed on behalf of each of the undersigned; and  

(iii)Each of the undersigned is responsible for the timely filing of such Schedule 13D/A-12 and any amendments thereto, and for the completeness and accuracy of the information therein concerning itself; but none of them is responsible for the completeness and accuracy if the information concerning the other persons making the filing, unless it knows or has reason to believe that such information is inaccurate.  

Sentient Global Resources Fund III, L.P.     By: Sentient GP III, L.P., General Partner            By: Sentient Executive GP III, Limited,                                     General Partner By:  /s/ Xxxxxx de Leeuw Xxxxxx de Leeuw, Director  Date: November 5, 2020	SGRF III Parallel I, L.P.     By: Sentient GP III, L.P., General Partner            By: Sentient Executive GP III, Limited,                                     General Partner By: /s/ Xxxxxx de Leeuw Xxxxxx de Leeuw, Director  Date: November 5, 2020
Sentient GP III, L.P. By:   /s/ Xxxxxx de Leeuw  Xxxxxx de Leeuw, Director  Date: November 5, 2020 Sentient Executive GP III, Limited By:  /s/ Xxxxxx de Leeuw Xxxxxx de Leeuw, Director  Date: November 5, 2020	Sentient Executive XX XX, Limited By:  /s/ Xxxxxx de Leeuw Xxxxxx de Leeuw, Director  Date: November 5, 2020 Sentient XX XX, L.P. By: /s/ Xxxxxx de Leeuw Xxxxxx de Leeuw, Director  Date: November 5, 2020
Sentient Global Resources Fund IV, L.P.    By: Sentient XX XX, L.P.,              its General Partner         By:  Sentient Executive XX XX, Limited,              its General Partner By: /s/ Xxxxxx de Leeuw Xxxxxx de Leeuw, Director  Date: November 5, 2020