Up 61% in a year, why is this ASX 300 gold stock getting hammered on Thursday?

S&P/ASX 300 Index (ASX: XKO) gold stock St Barbara Ltd (ASX: SBM) is sliding today.

St Barabara shares closed yesterday trading for 47 cents. In morning trade on Thursday, shares are changing hands for 45 cents apiece, down 3.8%.

For some context, the ASX 300 is down 0.7% at this same time.

This follows the release of St Barbara's June quarter update (Q4 FY 2026).

Here's what's happening.

ASX 300 gold stock restarting mothballed operations

It was an eventful quarter for St Barbara, with the miner approving the Final Investment Decision to proceed with the restart of its Touquoy gold mine, located in Canada. With recruitment now underway, the ASX 300 gold stock is aiming for the official reopening in November.

Earlier this week, St Barbara also reported on a 500,000 ounce (0.5 Moz) increase in the Mineral Resources Estimate (MRE) for its 15-Mile Processing Hub Project, also in Canada. The updated MRE for the project now stands at of 62.4 Mt @ 1.2 g/t Au containing 2.5 million ounces of gold. St Barbara is targeting a Final Investment Decision for the project in mid-2027.

Over the three months to 30 June, St Barbara's attributable gold production came out to 7,329 ounces, beating the miner's updated guidance.

The quarter saw the ASX 300 gold stock sell 6,700 ounces from its JV New Simberi project, located in Papua New Guinea. St Barbara received an average price of $6,314 an ounce. The company reported a Q4 all-in sustaining cost (AISC) for New Simberi of $4,514 an ounce.

St Barbara also sold 187 ounces sold from Touquoy for an average price of $6,572 an ounce.

Turning to the balance sheet, as at 30 June the company reported a cash balance of $475 million along with $21 million in attributable New Simberi cash and bullion.

What did St Barbara management say?

Commenting on the results that have yet to lift the ASX 300 gold stock today, St Barbara managing director and CEO Andrew Strelein said, "This has been a transformational quarter for St Barbara."

Drilling into New Simberi, Strelein added:

At New Simberi, construction of our US$333 million expansion with Lingbao Gold Group is progressing well, with earthworks, the ball mill delivery and the new wharf all advancing to schedule.

As for the company's financial position, Strelein said:

Importantly, we remain financially strong, with $509 million in cash, gold and investments, leaving St Barbara fully funded to deliver all three growth projects. New Simberi's operational performance continued to improve, as the operation increased production again and delivered cashflow to the business.

The post Up 61% in a year, why is this ASX 300 gold stock getting hammered on Thursday? appeared first on The Motley Fool Australia.

Motley Fool contributor Bernd Struben has no position in any of the stocks mentioned. The Motley Fool Australia's parent company Motley Fool Holdings Inc. has no position in any of the stocks mentioned. The Motley Fool Australia has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy. This article contains general investment advice only (under AFSL 400691). Authorised by Scott Phillips.

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