Thank you, Tito. Good morning, and good afternoon, everyone. Please, let's move to Slide 7. Beginning with the chart on your upper left, consolidated net revenue in third quarter 2021 was $655 million, up 22% compared to the same period a year ago, mainly driven by higher metal prices and by product contribution, which was partially offset by lower amount of sales volume and the silver streaming adjustment. In the third quarter, Nexa recognized a reduction of $19 million as a remeasurement adjustment in its silver streaming revenues, given forecasted higher long-term prices and the updated mining plan for Cerro Lindo.
Also for the quarter, Nexa recognized a recovery energy cost of $10 million related to undue costs paid by our energy power plants in the past. These non-recurring items had a negative net impact of $9 million in our adjusted EBITDA of $155 million. Compared to third quarter 2020, adjusted EBITDA increased by 2%, mostly driven by the Mining segment performance. In the next slide, we will discuss in further details our segment's performance.
On Slide 8 and 9, I will comment on our Mining segment results. Zinc equivalent production reached 136,000 tons, down 1% year-over-year, while remaining flat compared to the previous quarter. Zinc production in the quarter decreased by 2% compared to both third quarter 2020 and second quarter 2021, mainly driven by lower zinc head grade and planned and unplanned maintenance shutdowns in Peru during the period. As Tito mentioned earlier, we are already operating at normal levels. In terms of net revenue, we reached $276 million in third quarter 2021, up 34% year-over-year, explained by higher average LME prices and lower benchmark treatment charges, which offset the negative impact of the silver streaming adjustment of $19 million in the quarter. Adjusted EBITDA for the Mining segment was $92 million compared to $67 million a year ago.
As you can see on Slide 9, this performance was mainly explained by the positive net price effect of $46 million due to higher zinc prices, lower treatment charges with a positive variation of $25 million and higher byproduct contribution, which were partially offset by the increase in operating costs, driven by increased maintenance and mine development costs in the period, higher workers' participation provisions due to better results, higher exploration and project evaluation expenses and the negative effect of $17 million with respect of silver streaming and energy cost adjustments. In the first 9 months of the year, adjusted EBITDA amounted to $331 million, strongly recovering from a year ago.
Consolidated mining cash cost was $0.23 per pound in third quarter 2021, down 32% compared to last year. This decrease was primarily driven by higher by-product credits and lower treatment charges, which were partially offset by lower zinc volumes and higher operating costs. Note that the operating costs in third quarter 2020 were temporarily reducing as operations in Peru were still ramping up after the maintenance shutdown due to COVID-19. Compared to second quarter 2021, cash costs increased by $0.09 per pound due to lower volumes and increased operating costs. We have revised our full year cash cost guidance for the Mining segment.
Although we are starting to see additional inflationary pressure in our mining operations, cash costs at Cerro Lindo and Atacocha mines have been better than expected due to continued higher by-product metal prices. Consequently, cash cost guidance for these 2 operations has been reduced. Consolidated cash cost guidance is now $0.23 per pound compared to our previous guidance of $0.33 per pound.
Now, let's turn to the Smelting segment results. On Slide 10 and 11, we will discuss our Smelting segment operational results. In third quarter 2021, metal sales amounted to 156,000 tons, down 2% year-over-year and 1% from second quarter 2021. The decrease in production was partially offset by the increase in resale of metal from third-parties. Net revenue in the quarter was $523 million, totaling $1.5 billion in the first 9 months of 2021, positively impacted by higher LME prices and sales volumes. Adjusted EBITDA for the Smelting segment in third quarter 2021 stood at $65 million compared with $86 million a year ago, driven by lower treatment charges and higher operating costs.
As you can see on Slide 11, this performance was mainly explained by lower treatment charges with a negative impact of $21 million and higher operating costs, driven by higher consumption of imported material, inflation, maintenance and energy costs, which were partially offset by the positive net price effect of $15 million related to higher LME prices and changes in market prices, resulting in quotation period adjustments and the energy cost adjustment of $80 million.
And before proceeding, I'd like to further discuss the treatment charge impact. As you know, for the majority of our third-party contracts, which are renewed during different periods throughout the year, we used the 3-year benchmark TC as a reference. So for this year, the reference price considers the treatment charge of 2021, 2020 and 2019. At the beginning of the year, we tend to receive raw material reference at all the TCs. And as demands evolve, our reference is closer to the treatment charge of the current year. Consequently, we are seeing a higher negative treatment charge impact in the third quarter compared to the previous quarter.
Going back to our results, in the first 9 months of the year, adjusted EBITDA increased by 29% to $241 million. In terms of cash costs, as you can see on the bottom right, consolidated mounting cash costs of $1.16 per pound in third quarter 2021, increased by 47% year-over-year, mainly driven by market-related factors such as higher zinc prices and lower treatment charges. We also updated our full year smelting cash cost guidance to $1.14 per pound compared to our previous guidance of $0.95 per pound, primarily driven by higher zinc prices. Operating costs have also been affected by higher energy prices due to the current Brazilian scenario as well as an increase in maintenance costs, which has also been affected by inflation.
I will now turn over the call to Rodrigo Menck, our CFO, who will provide more detailed information about our balance sheet. Menck, please.