At depth at Gossan Hill, significant investment has been made since the IPO of 29Metals in 2021 to enable mining of Golden Grove's highest-grade ore reserve, Xantho Extended. After the recent interruptions, we expect to recommence sustainable production from Xantho Extended during the December quarter. From the end of 2026, we will also have Oizon coming online, another high-grade copper ore source at Gossan Hill. As we bring together the recovery of Xantho Extended, the development of Gossan Valley, and the integration of new ore sources like Oizon, along with the rest of Gossan Hill, you can see how the full potential of Golden Grove really comes together for 2027 and beyond. Since the IPO, Golden Grove has undergone significant investment to optimize the asset for the long term.
Investment in Xantho Extended, the investment in progress at Gossan Valley will bring those two highest-grade ore sources into the mine plan. We have had substantial investment in surface infrastructure. You can see here the PACE plant, triple sequential flotation, most recently the long-term tailings storage facility that will lower the life of mine tailings costs for the life of the mine, and then Gossan Valley. We are nearing the end of this significant investment phase, bringing high-grade ore sources through. From the end of 2026, we will see a reduction in capital expenditures, ramp up of mining from these high-grade ore sources, Xantho Extended, Oizon, and Gossan Valley. You can see on this slide the positive contribution these ore sources are expected to have on mill throughput and grades.
When we bring on Xantho Extended and Oizon, high-grade ore sources from Gossan Hill, we ramp those up. We bring on Gossan Valley, the new mine, high-grade production flexibility coming in. You can see an optimized and more flexible mine plan for Golden Grove, which is going to deliver more tons, higher grade to the mill, supporting metal production growth and free cash flow generation. You can see ore and grade 25% up as we bring that online. We are already on a journey of improved operational and financial outcomes at Golden Grove. You can see from 2023 to 2025, a 345% increase in EBITDA and 11% reduction in unit costs. The asset does have an impressive decades-long history of mine life extensions, and ongoing resource extension drilling continues to provide confidence that Golden Grove will deliver for decades to come.
Every intercept on this page has been released in the last 12 months, all of them resource extension intercepts. Lots of high-grade copper and zinc extending our existing ore bodies and adding mine life and lots of high-grade gold and silver intercepts as pretty handy byproducts in this day and age. Too many phenomenal intercepts to go through them all, but a couple to call out, particularly up the top at Tryall, up to 20 m at 2.8% copper at an ore source that is very shallow in the mine, short trucking distances, existing development, which is going to allow incorporation into our near-term mine plans. Drilling continues at Hougoumont Extended and Oizon with intercepts like 30 m at 17% zinc, 15 m at 2.6% copper.
Additionally, resource extensions have shown that Hougoumont Extended and Oizon are converging at depth as one large mineralized system, which will enable future mining cost efficiencies with the shared infrastructure already in that area. Across the board, lots of high-grade resource extension results coming from the exploration program, which gives us confidence on ongoing mine life extension for many years to come. 30 years and counting. You can see on this the 30+ year history of growth. Gossan Hill and Scuddles on the right-hand side. On the left, for the first time in 30 years, opening the new mining front at Gossan Valley, which still remains open at depth. Who knows what that could turn out to be? The same as 30 years ago at Gossan Hill and Scuddles.
Once underground, we're going to get into that resource extension drilling and just aim to build on Golden Grove's long history of exploration success. We see a really bright future at Golden Grove. We are nearing the end of this significant investment phase to enable the higher-grade ore sources. From the end of 2026, we expect a reduction in capital expenditures and a progressive ramp-up of mining from Xantho Extended, Oizon, and Gossan Valley. There's still a lot of exploration potential that we're looking to unlock. Now to Capricorn Copper, where the size of the prize is significant. 64 million tonnes in mineral resources, 1.2 million tonnes of contained copper, established surface infrastructure, established development right to the ore body of Touched It, all within the Mount Isa Inlier Province. We've got a low capital intensity brownfields restart project.
Capricorn is expected to double our group's copper metal production and contribute significant EBITDA. In 2021 and 2022, the last two full years of operation at Capricorn Copper, the asset delivered AUD 110 million and AUD 66 million of EBITDA respectively, and this is at $4 per pound copper prices. It's expected to produce a very strong all-in sustaining cost margins with current prices, as we've heard, beyond $6 per pound. The team are making excellent progress on the restart of production of the asset. Since I joined in 2024, the focus has been on reduction of site water levels and an approval for a long-term tailings storage facility. They have been and are the imperatives for a restart of production. It felt like all I got to talk about for the first couple of years was water.
During the 2025, 2026 wet season, the team were able to again dramatically reduce the site water levels, meaning site water levels are no longer an impediment to a restart of production. I'm looking forward to stopping talking about water. An approval for a long-term tailings storage facility, that's a critical path imperative for a restart of production. Working towards and with the government, a response to the regulator's request for information. We'll have that in the September quarter. Again, we're planning for success. A definitive feasibility study, progressing that so that we can accelerate a restart of production upon the approval of that tailings storage facility. Then funding, then FID. We see a really bright future at Capricorn Copper.
Tier 1 location, large copper metal endowment, a low capital intensity brownfields expansion instating up to 30,000 tons per annum of copper production, and lots of geological upside to enable future potential expansion of mineral resources and production. Why invest in 29Metals? Well, globally, copper supply is challenged. New mines are becoming harder to find, lower grade, and harder to mine. On the demand side as well, electrifiers we're going to need a lot more copper. This favorable copper market supply dynamic is shown in prices and the behaviors of all the players in the market across the sector. You can see those that don't have copper want it, and those that already have copper, well, they want even more. 29Metals, we remain really well-positioned to capitalize on this favorable copper market backdrop.
Quite simply, we have a lot of copper, over two million tons of contained copper and mineral resources across two Australian-based assets, both with long life potential and significant geological upside. The team remain focused on leveraging this position by delivering safe, reliable production and delivering on our growth plans. We say 29Metals is worth a look and if you've already had a look, well, it's worth another look because things are potentially very different going forward than looking back. Thank you.