By any company in the last 12 months. This is a team that you can see from those company logos below that has the experience of success, of course, the challenges that this industry goes through at other companies that comes together to build Minerals 260. For anyone new to the story, Bullabulling sits 65 kilometers from Kalgoorlie on a sealed highway in a jurisdiction that produces 70% of Australia's gold. You would not want to build a mine anywhere else in Australia, in my view. Existing infrastructure, the workforce, supply chains are already in place. It is one of our biggest advantages to our project beca use we're not opening up a new mining district, we're just plugging into an existing world-class one. Two weeks ago, we released our second upgrade in the last 12 months to the resource.
In December last year, we grew the resource from 2.3 to 4.5, and we were thrilled with that. Again, two weeks ago, Bullabulling grew another 1.7 million ounces to 6.2. 70% of it sits in the indicated category, and more importantly, we've maintained the head grade. This has really become one of my favorite slides. This is our journey over the last 12 months. That resource in April 2025, it's the same image I presented here 12 months ago, December, and now obviously two weeks ago with new resource. Those figures below is really what's driven our success. An incredible dedication to drilling, which is a key feature of Tim Goyder's companies, and that's why he's been so successful across multiple companies.
The acquisition of over 1,000 square kilometers, mostly contiguous to our project, has also unlocked this resource, which I'll show you in a moment. From a value add perspective, one of the reasons why we've been able to compound our value 400% above the gold price over the last 12 months is that discovery cost. We acquired this asset for AUD 72 an ounce. We grew it for AUD 14 an ounce in December, and we grew it for AUD 12 an ounce just a couple of weeks ago. Our current trading multiple is something like AUD 200 an ounce. This is where it sits compared to every other undeveloped gold project in Australia. Last year, we were middle of the pack. This year, we're leaping forward.
We are now genuinely a Tier 1 asset in Australia. Importantly, we don't stop. This resource remains open. North of Dixon, south of Kraken, west of Gibraltar. The strike length of this resource today is just under nine kilometers. The potential strike length of this is 20. This is because 12 months ago when I stood here, the tenement boundaries to the north and south constrained that resource potential. No longer, we acquired those tenements several months ago. Mineralization and geology doesn't stop at a tenement boundary. What have we done with that resource? How are we converting that resource into what we believe is going to be a fantastic operation? In December, we published that resource.
T hat was used for the PFS, which then was the basis for that two and a half million ounce reserve, where 85% of that indicated material converted to a reserve. The DFS, which is already underway, will be supported by the new 6.2 million ounce resource, which includes 4.4 million ounces of indicated. We're very confident that the reserve continues to grow when we release the new reserve with the DFS early 2027. Our development strategy is to stage our growth into production. If you balance risk, value, capability, capital, this is what many companies do. We did it at Carrapateena with OZ Minerals, and it's a very common approach with large scale and also growing assets.
More importantly, our growth is not a discrete separate event or discrete investments, but we've embedded growth into our designs, which ensures ramping up to our aspiration of 200,000 ounces a year is efficient, capital light, and lower risk. The PFS numbers for the base case, which will generate 150,000 ounces a year, speak for themselves. A post-tax NPV of AUD 2.3 billion, an IRR of 43%, a two-year payback with an AISC of AUD 2,500. Comfortably in the lower half of the Australian cost curve. AUD 560 million of construction capital delivers 19 years of production and AUD 330 million average of free cash flow. That's not an EBITDA, but that's free cash flow. This will be the foundations of the growth for the business going forward. Long life, high margin, large scale, compelling value.
This is the best way to describe Bullabulling. First production targeted for the end of 2028 and growth already designed into stage 1 means we're serious about achieving that 200,000 ounces. A key feature becoming increasingly important for Australian projects is approvals, ours are our strength. Sitting in the location that we are, a well-established mining jurisdiction, we have a land use agreement already with our traditional owners, more importantly, an excellent and genuine relationship with them to work together. Our Western Australia only pathway to mining and development approvals ensures this doesn't get stuck, unfortunately, in a federal system, which is becoming incredibly challenging for this industry. This time last year, we didn't have a reserve. Now we have 2.5 million ounces in reserve, and it's the largest undeveloped gold reserve in Australia not owned by a producer.
This reserve was based off that four and a half million ounce resource that I mentioned that we released in December, where 85% of that indicated material converted. It's the same story with the reserve as it is with the resource. On reserves, Bullabulling now ranks amongst the largest undeveloped gold project in Australia. We've been very deliberate about thinking about growth from the very beginning. Stage 1 will be a five million ton plant, we're building the crushing, thickening, and materials handling infrastructure, and space to support seven and a half million tons a year, which will deliver that 200,000 ounces via a capital light increase in the early years of production. We release an expansion study alongside the DFS early next year. Our approvals are tracking to plan.
We received our mine development and closure proposals, approvals, sorry, for our village and water infrastructure earlier this year. The approvals, which we'll piggyback off the back of those, will be submitted later this month. Our resource sits on a granted mining lease that was, has been established for many years, we've got a streamlined route through that full approval under the WA state pathway. None of that happens with a genuine social license to operate. We have a native title land use agreement, like I said. We are surrounded by a long-standing supportive mining community, which we will continue to invest in. This, again, is one of our competitive advantages. This is unique. Nobody has ever started construction of their project before finishing a PFS.
This is what the ground looks like today. In April, we signed a contract with ATCO to commence construction of a 400-person village, and construction started in May. Earthworks, room manufacturing has commenced, and the first rooms will arrive next month. Water bores are being drilled and tested right now. 400 rooms are targeted to be operational to coincide with the completion of the DFS and commencement of full construction. This camp will support both construction and then our full, our operations. Grade control started last month. The first 30,000 meters has been completed, which is a significant step to de-risking our operations going forward. None of this happens without funding. Unique to us, we secured one of the largest, or the largest investment by Franco-Nevada ever in Australia.
AUD 220 million split between a AUD 170 million royalty and a AUD 50 million equity placement taken at premium to the market at the time. Franco-Nevada is the largest royalty and the best royalty company in the world, they don't write a check without significant and exhaustive technical due diligence. We couldn't be more pleased with this deal, and the team at Franco-Nevada are now considered genuine partners in this project. Yes, like all other development projects, we do need further funding. Beyond Franco-Nevada, we are running a highly competitive debt process with 10 domestic and international banks, targeting finalization of those terms to coincide with FID, then backed by that strong shareholder base that can really support us if we do need equity in the future.
This is our development plan. It is the exact same plan that we had last year. The big difference now are these green ticks. We have delivered on everything that we said we would do in the last 12 months, either on schedule or ahead of it. What is left is the DFS final approvals and FID in the first quarter of next year. First prod uction of fourth quarter 2028 is the same target that we are holding to from 12 months ago. We said we would deliver this timetable last year, and we are still on track to achieve it. 12 months ago, 2.3 million ounces. Today, 6.2. We had not completed a study, now we have. We are fast-forwarding to production.
It is the same company, the same project, and the same project, significantly different 12 months later through that execution and delivery of our plan. Thank you, and I look forward to updating you again next.