EXHIBIT 99.1
JOINT FILING AGREEMENT
Each of the undersigned hereby agrees that this Amendment No. 23 to the statement on Schedule 13D is being filed with the Securities and Exchange Commission on behalf of each of the undersigned pursuant to Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.
Date: June 19, 2020
| Glencore AG | |||
| By: | /s/ Stephan Huber | ||
| Name: | Stephan Huber | ||
| Title: | Director | ||
| By: | /s/ Martin Haering | ||
| Name: | Martin Haering | ||
| Title: | Director | ||
| Glencore International AG | |||
| By: | /s/ Martin Haering | ||
| Name: | Martin Haering | ||
| Title: | Officer | ||
| By: | /s/ John Burton | ||
| Name: | John Burton | ||
| Title: | Director | ||
| Glencore plc | |||
| By: | /s/ Ivan Glasenberg | ||
| Name: | Ivan Glasenberg | ||
| Title: | CEO | ||
| By: | /s/ John Burton | ||
| Name: | John Burton | ||
| Title: | Company Secretary | ||
