Good morning, welcome to the Perseus Mining investor webinar and conference call. All 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. Alternatively, you can ask a question in the Q&A panel within Zoom. I'll now hand over to Perseus CEO and Managing Director, Jeff Quartermaine. Thank you, Jeff.
Thank you, Nathan. Welcome to Perseus Mining's webinar to discuss our interim financial report for the six months ending 31st of December 2022. I'm joined on this call today by my colleague, Lee-Anne de Bruin, our Chief Financial Officer, who will take you through the details of the financial report that was released to the market yesterday. A little ahead of schedule, I must admit. Circumstances were such that we had little choice in that matter. Lee-Anne will also be available later in the call, as will I, to answer any detailed questions that you have about our financial results, or indeed our comprehensive financial report, or any aspects of our business, come to that. Before passing to Lee-Anne, let me just say that calendar 2022 has been an excellent year for Perseus.
In January, we reported our operational results in our December quarter activities report. In this report, we advised that for the December half-year, our gold production had exceeded market guidance and our All-in site costs had come in lower than the market guidance. The financial report that was released yesterday translates that excellent operating performance into equally excellent financial results. Without further ado, I'll pass to Lee-Anne de Bruin to give you an overview of the results that have been achieved before handing back to me for some closing remarks and then a Q&A opportunity. Lee-Anne, please take it away.
Thanks, Jeff. It does give me great pleasure to present our financial results for December 2022 half year. Obviously we've got the normal cautionaries, and then we'll move on to the first slide. Gold production of 268,000 ounces this six months, was in line with our target production rate of 500,000 oz per annum. The 268,000 oz exceeded the production guidance for the six months of 240,000-265,000 oz. The All-in site costs of $930 per oz was below the cost guidance ranges for the six months to December of $1,000-$1,100 per oz.
Our focus on achieving high gold price resulted in a gold sold at $1,724 per oz on average, which is largely in line with the average spot price for the six-month period. This continued good performance of the operations is obviously positioning the group well for future growth. Moving on to the fact that this all translated into strong performance across all financial metrics. Revenue was up to AUD 665 million, 22% on the previous comparative period. This was attributable to sustained strong performance from our Yaouré and Sissingué operations, and a really strong improvement performance from Edikan. It was also slightly helped by the 4% increase in overall price achieved of the $1,724 per oz.
Profit after tax of AUD 203 million was up 60% on the comparative period. Was due to the increased revenues as well as our continued focus on maintaining costs in this inflationary environment. Operating cash flow of AUD 300 million, up 22% on December 2021, boosted by the strong operational performance at all three of our sites. Net tangible assets increased to AUD 1.4 billion, up 38%, boosted by the increased cash and cash equivalents, which went from AUD 426 million- AUD 529 million. In addition, which we'll talk a little bit later, the Perseus board approved an interim sustainable dividend. This then solid increase in all our earning metrics translated into growth earnings. Next slide, please.
We delivered the revenue increase of 22%, delivered a 40% increase in the EBITDA of AUD 355 million. Gross profit from operations increasing 62% to AUD 249 million, which included a 7% increase in depreciation and amortization on the comparative period. Profit before tax increase of 80% to AUD 231 million. Income tax has increased during the year to AUD 28 million, and this is largely due to the improved performance of our Edikan operation, where taxes are now being paid, and dividends declared up on the Ivorian subsidiaries, which attract withholding tax. Our profit after tax is up 60% to AUD 203 million.
All of this delivering a Basic earnings per share of $0.1324 per share, up 46%. An earnings per ounce, importantly, of $775 per oz, up 45%. Moving on to where we focus, which is on continued is growth in cash flow. This year we delivered a 22% increase in the Operating cash flow of $300 million, which equates to Operating cash flow per share of $0.2195, up 9.5% on the December 2021 six-month period. An Operating cash flow per ounce of AUD 1,117 per oz, up 9.6% on the previous period. Our growth in tangible assets.
In the six months to December 2022, cash and bullion position has increased 24% from AUD 476 million to AUD 594 million, or in U.S. dollar terms from $328 million- $405 million, which included the repayment of $50 million to bring the debt position down to nil. Currently, we also have $100 million of undrawn liquidity in this corporate loan facility. The current balance sheet is strong and has total assets of AUD 2.1 billion and net tangible assets of AUD 1.4 billion, which equates to a net tangible assets of AUD 1.03 per share.
The trend of gold production remains attractive and as do our margins, and this slide sort of demonstrates the performance of Perseus and our operations over the last couple of quarters. The 2022 calendar year was a record annual gold production for Perseus at 521,220 oz, with our operational teams at all three sites delivering to plan. The All-in site costs, pleasingly, is 4% down year-on-year at $940 per ounce, with our continued focus on containing costs, despite the current inflationary environment we operate in.
As I've mentioned, the average gold price was $1,714 per oz. This in turn delivered a cash margin of $773 per oz sold, culminating in notional cash flows of $402 million for the calendar year. Moving on to production and cost market guidance for the June 2023 half year.
Giving consideration to the performance to date and for our forecast for the next six months, we've set our guidance for the next six months for the three operations, which overall is delivering production of between 498,000-528,000 oz for the financial year end, ended June 2023, and an All-in site costs of between $1,000-$1,100 per oz for the financial year end of 2023, with Edikan and Yaouré offsetting the All-in site costs for Sissingué as it transitions to its satellite pit operations, namely ramping up Fimbiasso and commencing the Sissingué Stage 4 cutback. Moving on to dividend declarations.
The Perseus Board, in line with its dividend policy, has declared a sustainable dividend of AUD 0.0106 per share, basically AUD 14.5 million, equating to a 1% annual yield based on the closing share price at the end of December 2022. In line with June 2022, at the end of June 2023 financial year, the Board will consider special dividends above the 1% annual yield whilst balancing capital structure and its capacity to fund corporate growth. That brings me to the end of the presentation, and I would like to pass on my thanks to our operational teams who have been the largest contributor to this excellent performance, and I'll hand over to Jeff, our CEO, to close off.
Well, thanks very much, Lee-Anne. That was an excellent summary, I'm sure you'll agree. Now, before opening the floor to questions, I'd just like to make a couple of quick observations. The impressive financial results that have been reported, along with the similarly high-quality operating results reported a few weeks ago, they don't occur by themselves. We do have excellent teams of people deployed at all four of our operating sites in Africa and in offices in Abidjan, Accra, Khartoum and Perth. They're all staffed by people who've worked tirelessly to deliver these results and to do so day in, day out. Now, it is hard work, and it requires a lot of tenacity, effort and sacrifice on their parts and on the parts of their families who support them, I might add, to achieve these outcomes.
I know that I speak for all of our shareholders and all members of the board when I publicly acknowledge the contribution that all employees have made, and I extend my personal sincere thanks to everybody. I know a lot of our employees do listen in to these webinars. To my way of thinking, it's fairly clear that Perseus is in excellent shape as a company. It's true that it hasn't always been this way, but we have progressively transformed this company from being a junior explorer to a mid-tier gold producer, developer, and explorer that consistently turns out high-quality results. We're building a very, very solid platform from which to face the future.
Now, in this regard, not only do we expect to continue performing operationally and financially at a high level, as indicated by the market guidance that Lee-Anne just mentioned, and certainly the results that we've delivered for the first half of this quarter support this statement. We also expect that, you know, opportunities will come our way to continue improving, continue prudently moving along the growth path. I say prudently because there is no shortage of ways to invest our hard-earned financial resources. Opportunities that create substantial value for shareholders are what we're looking for, and these are a bit harder to find. Now, we do intend to continue searching for these opportunities, though, and when the stars do align, we will execute as we've successfully done in the past.
Perseus has a very bright future ahead of it, in my opinion. Those of you who are existing shareholders, well done in backing your judgment thus far. For those who aren't yet shareholders, Perseus is a company that warrants serious consideration if you're looking for a quality investment in gold. Thank you very much for your attention today. This brings our presentation to a close, and now Lee-Anne and I are happy to take any questions that any of our listeners may have.
Thank you, Jeff. If you would like to ask a question directly to the company, please use the raise hand function within Zoom. For those phoning in, please dial star nine. Jeff, it looks like there's no further questions at this time, so I'll now hand back to you for closing remarks.
Okay. Well, look, thanks for that. Hopefully, the fact that there are no questions is an indication that our reporting is very clear and with no ambiguity. In any event, thanks very much for your attendance today. As I've said, we do look forward to continuing bringing you very solid results from this company going forward. Thank you.