Central to that effort, we intend to pay down debt and-or build cash in order to return to a minimal net debt position. With Leer South longwall now commissioned and in ramp up mode we intend as previously stated to prioritize the restoration of our balance sheet to its pre 2020 level. Turning to our rapidly evolving capital allocation plans.
#The money team snapback free
In doing so we set the stage for upward momentum in sales volumes, operating margins and free cash flow yield this coming quarter and in 2022. In short, we continue to execute on our clear and actionable strategy for long-term growth and value creation throughout the quarter. Flexed up production to capitalize on strong pricing in both domestic and international markets and leverage those near term volumes into a greatly expanded book of higher priced business that only in 2021, but also in the outer years. We further reduced our Powder River Basin and with additional final reclamation work at Coal Creek. We generated approximately $58 million and gross margin or a 43% improvement from the prior quarter. In our legacy thermal segment where we are focused on simultaneously harvesting cash and pairing down our long-term closure obligations. We achieved another strong shipping quarter and maintained our highly competitive cost structure despite the planned pre-start-up outage at Leer South and an increase in sale sensitive costs related to higher sales prices. Capitalized on strong market dynamics, generating $118 million in gross margin, which was nearly 100% increase for the segment from the prior period. In our core metallurgical segment, we commenced longwall production at the Leer South mine after a well-executed 2.5-year build out. I'm pleased to report that the Arch team continue to deliver across a wide range of strategic and operating objectives during the last quarter. We're glad you could join us on the call today. Lang - Chief Executive Officer and President With that, I'll now turn the call over to Paul. After our formal remarks we'll be happy to take questions.
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Also participating on this morning's call will be Paul Lang, our CEO, John Drexler, our COO and Matt Giljum our CFO. I'd also like to remind you that you can find a reconciliation of the non-GAAP financial measures that we plan to discuss this morning at the end of our press release, a copy of which we have posted in the Investors section of our website at.
#The money team snapback update
We do not undertake to update our forward-looking statements whether as a result of new information, future events or otherwise, except as may be required by law. These uncertainties which are described in more detail in the annual and quarterly reports that we filed with the SEC, may cause our actual future results to be materially different than those expressed in our forward-looking statements. Forward-looking statements by their nature address matters that are to different degrees uncertain. According to the Private Securities Litigation Reform Act. Before we begin, let me remind you that certain statements made during this call, including statements relating to our expected future business and financial performance, may be considered forward-looking statements. I want to assure you that the team is widely spaced and following CDC guidelines closely.
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While we are conducting this morning's call from Arch's boardroom.