JOINT FILING AGREEMENT
EXHIBIT 99.1
Each of the undersigned hereby agrees that this Amendment No. 17 to the statement on Schedule 13D is being filed with the United States Securities and Exchange Commission on behalf of each of the undersigned pursuant to Rule 13d-1(k) under the United States Securities Exchange Act of 1934, as amended.
Dated: December 18, 2015
| Glencore AG |
| By: | /s/ Xxxxxx Xxxxx | |
| Name: | Xxxxxx Xxxxx | |
| Title: | Officer | |
| By: | /s/ Xxxxxxx Xxxxx | |
| Name: | Xxxxxxx Xxxxx | |
| Title: | Officer |
| Glencore International AG |
| By: | /s/ Aristotelis Mistakidis | |
| Name: | Aristotelis Mistakidis | |
| Title: | Officer | |
| By: | /s/ Xxxxxx Xxxxxxx | |
| Name: | Xxxxxx Xxxxxxx | |
| Title: | Officer |
| Glencore plc |
| By: | /s/ Xxxx Xxxxxx | |
| Name: | Xxxx Xxxxxx | |
| Title: | Company Secretary |
