Attendees are in a listen-only mode. If you would like to ask a question directly to the company, please use the raise hand function within Zoom. For those phoning in, dial star nine. I'll now hand over to Perseus Executive Chairman and CEO Jeff Quartermaine. Thank you, Jeff.
Thank you very much, Nathan, and welcome to this webinar today to discuss our December 2023 half-year financial results. As usual, I'm joined on the call with our CFO, Lee-Anne de Bruin, who's working with me here in Perth, and Lee-Anne's going to do most of the heavy lifting today, taking you through the results, but we'll both be available to answer questions at the conclusion.
Before I pass to Lee-Anne, let me just say that the results that we've published today are the financial continuation of some very strong performance that we reported about a month ago in our quarterly report. And what we have done through the strong operating and financial performance, I believe, is to continue to cement our position as a very profitable mid-tier gold producer that consistently delivers on its promises and exceeds targets. Without further ado, I'll pass to Lee-Anne to take you through the results. Thanks, Lee-Anne.
Thanks, Jeff. It's pleasing to be able to present another set of strong financial results for the Perseus Group. As always, this is achieved through the immense efforts of our Perseus team. I would note upfront that Perseus made a change to its presentation currency from Australian dollar to US dollar in this half-year, and going forward, we'll present all future financials in US dollars. The six months to December 2023 have delivered a market-leading performance, keeping Perseus firmly on track to fund its growth objectives and to deliver benefits to all our stakeholders. As you'll see in this slide, our gold produced for the six months was circa 262,000 ounces, sitting well in the upper half of our production guidance range for the period.
We achieved an all-in site cost of $979 per ounce, below the cost guidance ranges. Our average gold price achieved was $1,951 per ounce, against an average spot price for the period of circa 1,950 per ounce. Notional cash flows for the period were $254 million, up 7% on the previous comparative period, taking our net cash and bullion balance to $642 million, an increase in the period of $120 million. Leveraging the strong operational performance, Perseus had gone on to produce another strong performance against its key financial metrics against the comparable period. Revenue, aided by improved average gold sales, was up 10% at $489 million. Profit after tax, up 21% at $165 million, despite a $19 million or almost 100% increase in our income tax expense for the period.
Operating cash flows remained steady, increasing 2% on the previous comparable period, despite a 270% or $17 million increase in our taxes payable due to increased taxes paid at Edikan or for improved performance and withholding taxes paid on dividends declared from the Ivorian operations. Net tangible assets increased 16% to $1.3 billion, and this is largely due to the increased cash and cash equivalents of $19 million, an increase in stockpile inventories of $32 million, and the increase in our equity investments through the acquisition of the 19.9% OreCorp Limited, which owns the Nyanzaga Gold Project in Tanzania. In line with the company's dividend policy, our board have considered and declared an interim dividend of AUD 0.0125 per share for the period.
The growth in earnings has continued, which is evident in the graph in front of you, and showing Perseus' performance over the period. Basically, we've got, against the 10% increase in revenue, EBITDA has increased 18% on the previous comparable period to $281 million, with a continued focus by our teams on costs, keeping costs of sales flat against the half-year 2022. Gross profit from operations was up 26% due to increased revenue, with depreciation and amortization flat at $70 million for the six months. Earnings per share is up 19%, delivering a $0.1061 per share, whilst earnings per ounce up 26% at $656 per ounce.
The operating cash flow from operations was up at $211 million, building on our ongoing growth in cash flow and has delivered for us an operating cash flow per share of $0.154 per share and an operating cash flow per ounce of $807 per ounce. The growth in cash flow has further strengthened the balance sheet of the group, ending the six months with $642 million in cash and bullion on our balance sheet. Net tangible assets, as I said previously, are up at $1.3 billion or US dollars per share. We remain with no interest-bearing debt, however. We still have our undrawn capacity of $300 million available for future growth opportunities and obviously future shareholder returns. As you can see from the slide, the Edikan, Yaouré, and Sissingué continue to produce at attractive margins.
We maintaining the all-in-site cost and production consistency for the operations has enabled the group to leverage the high gold prices, generating steady increases in the cash margins and our cash balances. On the slide, we just make the point that in line with Perseus' dividend policy, where we aim to reward shareholders while maintaining our balanced capital structure and, of course, capital capacity to fund our corporate growth. Giving consideration to that, the board declared an interim dividend of AUD 0.0125, and this equates to a 1.33% annual yield. Thanks. I'm now going to hand over to Jeff to conclude. Over to you, Jeff.
Thanks very much, Lee-Anne, for that very comprehensive run-through, which clearly establishes that the recent past has been a very good period for us. Now, oops, sorry. I'm just moving around on this presentation here. We've kind of lost the looking to the future, our guidance that we have given to the market for the second half of this financial year has remained steady on what was already circulated. This puts us into another position where we're expecting to produce in excess of 500,000 ounces again and to maintain our all-in costs not too distant from current levels.
We've started off the period very strongly, I should say, and based on where we are, almost two months into the first quarter, we're predicting at this stage of the game to finish in the upper half of the guidance range should everything stay normal from here on in. And our costs for the first month of the period are actually well below the bottom end of that cost range that we have forecast. And the very good cost performance this period is not a function of slowing up on mining activities. In fact, actually, we've accelerated our mining, so it was just a very good performance across the board.
Now, what these excellent results have done, I think, is put us in the position, as Lee-Anne said, where not only are we able to return capital to our shareholders through our ongoing dividend policy, but it's also put us in the position to continue to upgrade the quality of our asset portfolio. This is a very key consideration in the minds of many of our investors. Now, I think people who have been following the company would have seen that we've made a number of releases to the market in the last couple of days. On Wednesday, we made an announcement about a joint venture that we have established with the mining arm of a Saudi-based conglomerate, where we have agreed to investigate, co-investing in opportunities in both the Arabian and the Nubian Shields.
These areas are prolific with mineralization and extremely underexplored in relation to the rest of Africa, largely due to geopolitical challenges. I would say that in partnering with a Saudi-based company as we are doing, it'll certainly assist us to navigate the cultural and geopolitical differences that are likely to be encountered in this part of the world, where we'll be targeting early-stage exploration in Saudi Arabia and later-stage projects elsewhere on the African continent. So that's an important initiative in our long-term growth projections. Yesterday, we put another release to the market outlining the exploration results that we have returned from our drilling programs, our organic growth programs at our Ivorian mines, Yaouré and Sissingué. Yaouré, in particular, shows enormous potential for materially adding to our mineral inventory, which in turn flows into the opportunity to extend the mine life of that mine for quite a number of years.
As it stands, we have 12 years ahead of us of open-pit and underground operations, as per the DFS that was released to the market last year. But these results that were published yesterday suggest a material extension is certainly not beyond the realms of possibility. And similarly, at Sissingué, on both the Sissingué and Fimbiasso mining leases, the drilling results there suggest the potential to extend the inventory and, more importantly, extend the life of the Sissingué operation. Now, as things stand, Sissingué has another three years of life ahead of it, but with this additional mineralization, a material extension for several more years is a possibility. We will release, of course, more information on this particular program as results come to hand, as we will, of course, with Yaouré and exploration around the Edikan mine.
Now, the other initiative that has been in the market of late, which is directly related to the upgrading of Perseus' asset portfolio, is the takeover offer that we have made for OreCorp, which, as Lee-Anne mentioned earlier, owns the Nyanzaga project in Tanzania. Now, as people would be aware, we filed our revised bidder statement with the ASX last Friday, and on Monday, our revised offer was distributed to OreCorp shareholders. The offer is now open and will remain open till March the 15th. We are somewhat intrigued by the thought processes that have been applied by the OreCorp board in failing to acknowledge the superiority of Perseus' offer compared to the competition, but that is clearly a matter for them. We do hope, though, that they will reconsider their position. But as I've said in the past, the shareholders will determine the outcome.
We have absolute faith in the fact that they will, more likely than not, take note of the independent experts' appraisal of the value of the company and compare this to where Perseus' offer sits, and then make a logical choice. Now, our application to the Tanzanian Fair Competition Commission, which seemed to be a point of distraction to the OreCorp board, has progressed very well. It's gone beyond the stage of advertising for comment, and no objections were raised relative to our potential investment into Tanzania. And we are now awaiting the formal approval of our application, which we are very confident will be received by the end of the month. Of course, at that point, any question regarding the superiority of our offer will vanish, and hopefully, nature will take its course.
I don't wish to say a whole lot more on the takeover at this point. I think the choice is obvious. For those OreCorp shareholders who wish to retain exposure to the Nyanzaga project and at the same time, of course, gain exposure to Perseus' impressive asset portfolio and operating results, as demonstrated by these excellent financial results today, we make the point that Perseus does trade very freely on the ASX and the TSX, and the stock is available for purchase with the cash that you will receive from us. I think those couple of items I've just raised go very clearly to the point that Perseus is in an excellent position right now. We're generating very, very good results.
We put ourselves into a very strong financial position, which allows us to consider carefully options to continue the growth of the company and firmly establish us as a leading mid-tier gold company. With that, we will bring the presentation to a halt and invite further questions or any questions that you may have at this particular time. Thank you very much.
Thanks, Jeff. Just a reminder, if you would like to ask a question directly to the company, please use the raise hand function within Zoom. Your first question comes from David Radclyffe at Global Mining Research. Please go ahead, David.
Hi. Good morning, Jeff and team. I appreciate you've currently got the bid out for OreCorp and you're looking for new opportunities in Saudi Arabia, which just shows that you're at that phase of looking for new growth opportunities. With that in mind, I was wondering whether you might potentially have any interest in the Akyem asset in Ghana, which Newmont has just announced that there's now a formal process for divesting that, given the fact that it's obviously not something you have to build but is an operating mine today.
Yes. We've noticed the publicity surrounding that, and I guess we have been aware that that may have been a possibility for some time now. Look, Akyem is in our backyard, so to speak. We've been operating in Ghana now for well, actually, since the beginning of this company, but certainly operating since 2012. So we certainly know our way around Ghana and have very strong relationships in country and have demonstrated our credibility as a respected partner of the communities and the government. So I think as a potential investor in that project, we're really well positioned. We're also positioned, as you heard from Lee-Anne's account earlier, that with the cash on balance sheet and the very strong cash flows, we are in a position where we could quite comfortably acquire that if the thing stacked up technically.
Now, I might say we haven't done any due diligence at all at this stage of the game, and there is a process running or going to be a process running. But we are broadly familiar with the asset, and as it turns out, a number of our employees were former employees of Newmont. So we do have a bit of an idea about the project. But we'll certainly investigate the opportunity, and if it makes sense, we'll take a very close look at the asset. And of course, it would fit very comfortably within our portfolio, I should think, if it meets our investment criteria.
Brilliant. Thanks, Jeff. I'll pass it on.
Thank you. Just a reminder, if you would like to ask a question directly to the company, please use the raise hand function within Zoom. We'll just give people a little bit of time. There are no further questions at this time, so I'll now hand back to Jeff for closing remarks. Thanks, Jeff.
Okay. Well, thanks, Nathan. I think we've pretty much said it all at this stage of the game. And certainly, there's a lot of information been published on the ASX platform today for people to really dive down into the details. Of course, going forward, if there is any clarification required on anything that we've either said in our releases or stated on this call this morning, please don't hesitate to contact us, and we'd be happy to expand where possible. But aside from that, we're looking to the future very much. There's lots of opportunities, and we have a very strong business here. So thank you for coming today, and we look forward to continuing to bring positive news.