Boss Energy's (ASX:BOE) joint venture partner, enCore Energy, ramped up the annualized production rate at the Alta Mesa central processing plant in Texas to 1.5 million pounds of uranium, according to a Tuesday Australian bourse filing.

The ramp-up follows the extraction and processing of 130,015 pounds of triuranium octoxide for the March quarter at an average cost of $36.11 per pound, the filing said.

The project also delivered 290,000 pounds of triuranium octoxide into sales contracts at an average realized price of $62.89 per pound, the filing added.

Of that, 29,126 pounds were transferred to Boss Energy, which owns a 30% stake in the project.

Shares of the company rose almost 4% in recent Tuesday trade.