It reported a loss of US$4.4 million, compared to a $10.1 million profit a year ago.
Net loss per share was 16.8c basic and 15.7c diluted, which were down from a profit of 0.6c/share for both categories a year ago.
Before factoring in exploration and finance costs, gross profit for the six-month period almost doubled year-on-year to $12.4 million, up from $5.8 million at the end of June 2017 on the back of production and improved selling prices.
Revenue for the half-year was $28.3 million, more than double the corresponding period's $12.8 million, with sales of 21,493 ounces of gold equivalent at a price of US$1,322 per ounce.
Total production from Patagonia's flagship Cap-Oeste mine in Argentina more than doubled to 23,069 ounces AuEq from 10,452oz a year ago. The company attributed its higher recoveries to the successful operation of the newly-installed crushing and agglomeration circuit and higher grades.
It maintained its full-year guidance of 45,000oz AuEq.
Patagonia had cash and cash equivalents of $564,000 at the end of June, down from $1.3 million at the end of December and $809,000 a year ago.
CEO Christopher van Tienhoven said the successful new circuit installation had improved production levels at Cap Oeste.
"Despite the current difficult economic situation in Argentina and the impact that the reintroduction of the export tax will have on our bottom line, from a technical point of view we have a lot to look forward to: progressing Calcatreu, evaluating and proceeding with the high-grade deposit underground at Cap-Oeste and potential positive results from our other exploration activities," he said.
Patagonia's shares were down 1.22% on the news Tuesday to 64.7p (US85c).