The US$740/t achieved compares to the $459-668/t recorded in the previous four quarters and represents a revenue to cost ratio of 3.3 to 1 - versus 2.5-2.9 to 1 in the previous four quarters.

And if the current quarter continues to track as it has started, another record could be in the offing, though managing director Tim Carstens offered a note of slight caution on the macro front when referring to inflation, Chinese city lockdowns for COVID, and the geopolitical situation in Europe.

Base's guidance for the full financial year remains unchanged.

Debt-free Base had cash at the end of March of $41.5 million, up from $37.1 million at the end of December and post a $26 million outlay for dividends - taking total distributions to shareholders over the past two years to $117 million (or A13.5c per share).

Meanwhile Base has initiated a study on the "rather exciting" monazite opportunity at its Toliara project in Madagascar as the long wait for agreement on fiscal terms for the world scale development continues.

Shares in Base were unchanged at 33c in Australian trade, capitalising the company at $389 million.