the initial industrial shutdowns , particularly in the automotive and oil and gas sectors , that drove significant reductions in steel demand and the idling of multiple blast furnaces globally , began to reverse in the third quarter of 2020 , leading to increasing steel demand and the restarting of many idled blast furnaces . in particular , domestic auto production returned to pre-shutdown levels in july , but has declined slightly since . the return of industrial production to pre-pandemic levels has been , and will continue to be uneven ; for example , oil and gas drilling activity , although increasing slowly , remains significantly depressed as compared to pre-pandemic levels . the return of overall industrial production to pre-covid-19 levels is also likely to be lengthy and , as we have seen in the fourth quarter of 2020 , is subject to setbacks should covid-19 become resurgent . during 2020 , demand destruction elicited a supply side response , as significant high cost coking coal mine idlings and slowdowns were announced in north america and globally . the overall production volume removed from the markets this year is significant . while some of the curtailed production has returned or can return to the market with the right price signal , we believe that the cash cost of a 60 significant portion of the currently curtailed coking coal production exceeds current prompt pricing . to date , due to our low cost structure , we have avoided idling any of our coking coal operations . longer term , we believe continued limited global capital investment in new coking coal production capacity , economic pressure on higher cost production sources , and production responses to the covid-19 pandemic will provide support to coking coal markets as demand continues to return to the steel production supply chain . during the fourth quarter of 2020 , a major trade dispute escalated between china , a major importer of coking coal , and australia , the world 's largest exporter of coking coal . specifically , china has effectively banned the import of coking coal from australia . this disrupted historical trade patterns , and led to pricing anomalies in the international coking coal markets . through most of the fourth quarter of the year ended december 31 , 2020 , the prompt index price for united states east coast high-vol a ( hva ) , our main product , low-vol ( lv ) , and even high-vol b ( hvb ) coking coal exceeded the prompt index price for australian east coast premium low volatile ( plv ) coking coal . recently the plv index has rapidly risen significantly , returning to a more historically normal price relationship between products . uncertainty and volatility in pricing and pricing relationships are likely until the larger trade dispute between china and australia is settled . while most of our committed but unpriced coking coal volume is linked to the united states east coast hva , lv , or hvb indexes , we do have approximately 1.1 million tons of committed but unpriced coking coal linked to the plv or other asia/pacific indexes for 2021. demand for domestic thermal coal remained significantly below the prior year due to historically low natural gas prices , covid-19 related commercial and industrial demand declines and the continued increase in subsidized renewable generation sources , particularly wind . natural gas pricing recovered in the second half of 2020 from historically low levels seen in the first half of 2020 , and as a result coal fired generation , particularly powder river basin fired generation , was competitive in many regions of the country during the second half of the year . production levels of natural gas were below the prior year 's levels , but storage levels remained significantly above last year 's levels . additionally , generator coal stockpiles declined during the second half of 2020 , but remain above historical averages based on days of burn . international thermal coal market pricing that had remained at levels that were uneconomic for all of our thermal operations for most of the year , increased significantly late in the year . by late december prompt international thermal coal pricing reached levels that can support economic exports from our west elk operation . similar to metallurgical markets discussed above , actions taken to combat the spread of covid-19 across many regions of the national and global economy continue to negatively impact thermal coal demand and supply . as a result , we expect domestic and global thermal markets to remain challenged . on september 29 , 2020 , the u.s. district court ruled against our proposed joint venture with peabody energy corporation that would have combined our powder river basin and colorado mining operations with peabody 's . following the ruling , we announced the termination of our joint venture efforts due to the significant investment of time and resources that would be required to conduct an appeal . in light of the unfavorable ruling and decision to terminate efforts on the joint venture , we continue to pursue other strategic alternatives for our thermal assets . these alternatives include , among other things , potential divestiture . we also continue to evaluate opportunities to shrink our operational footprint at those mines , reduce their asset retirement obligations , and establish self-funding mechanisms to address those long-term liabilities . in alignment with our desire to shrink our operational footprint and associated liabilities , we have committed to closing our coal creek operation in the powder river basin once all currently committed sales have been shipped by the end of 2022 or sooner . story_separator_special_tag longwall operations accounted for approximately 60 % of our shipment volume in the year ended december 31 , 2020 and 71 % of our shipment volume in the prior year . other thermal — adjusted ebitda for the year ended december 31 , 2020 declined from the year ended december 31 , 2019 due to reduced sales volume , lower pricing , and increased cash cost per ton sold . all of these metrics are impacted by the inclusion in the year ended december 31 , 2019 of our former coal-mac operation , which was sold in december 2019. coal-mac provided approximately 2.1 million tons sold in the year ended december 31 , 2019. tons sold from ongoing operations declined approximately 2.2 million tons in the year ended december 31 , 2020 , as low natural gas pricing , increased renewable generation , and uneconomic international pricing impacted volume . in addition , in late march of 2020 we temporarily idled our viper mine due to nonperformance of the mine 's primary customer . the customer restarted deliveries in early may , and we reopened the mine at approximately the same time . in late december of 2020 , prompt international thermal coal pricing increased to levels that can support economic exports from our west elk operation but the international thermal coal pricing is volatile . on december 31 , 2020 , we sold our other thermal operation , viper , to knight hawk holdings , llc . for further information on the sale of viper , please see note 4 , “ divestitures ” to the consolidated financial statements . in december of the year ended december 31 , 2019 , we sold our other thermal operation , coal-mac llc , to condor holdings llc . for further information on the sale of coal-mac llc , please see note 4 , “ divestitures ” to the consolidated financial statements . ​ 67 ​ reconciliation of non-gaap measures non-gaap segment coal sales per ton sold non-gaap segment coal sales per ton sold is calculated as segment coal sales revenues divided by segment tons sold . segment coal sales revenues are adjusted for transportation costs , and may be adjusted for other items that , due to generally accepted accounting principles , are classified in “ other income ” on the consolidated income statements , but relate to price protection on the sale of coal . segment coal sales per ton sold is not a measure of financial performance in accordance with generally accepted accounting principles . we believe segment coal sales per ton sold provides useful information to investors as it better reflects our revenue for the quality of coal sold and our operating results by including all income from coal sales . the adjustments made to arrive at these measures are significant in understanding and assessing our financial condition . therefore , segment coal sales revenues should not be considered in isolation , nor as an alternative to coal sales revenues under generally accepted accounting principles . ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ powder river ​ ​ other idle and ​ ​ year ended december 31 , 2020 ​ basin ​ metallurgical ​ thermal ​ other ​ consolidated ( in thousands ) ​ ​ ​ ​ ​ gaap revenues in the condensed consolidated statements of operations ​ $ 662,135 ​ $ 641,536 ​ $ 139,497 ​ $ 24,424 ​ $ 1,467,592 less : adjustments to reconcile to non-gaap segment coal sales revenue ​ ​ ​ ​ ​ coal risk management derivative settlements classified in `` other income `` ​ — ​ ( 577 ) ​ ( 8,632 ) ​ — ​ ( 9,209 ) coal sales revenues from idled or otherwise disposed operations not included in segments ​ — ​ — ​ — ​ 24,322 ​ 24,322 transportation costs ​ 13,625 ​ 124,494 ​ 41,852 ​ 102 ​ 180,073 non-gaap segment coal sales revenues ​ $ 648,510 ​ $ 517,619 ​ $ 106,277 ​ $ — ​ $ 1,272,406 tons sold ​ 52,366 ​ 6,979 ​ 3,356 ​ ​ coal sales per ton sold ​ $ 12.38 ​ $ 74.17 ​ $ 31.67 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ powder river ​ ​ other idle and ​ ​ year ended december 31 , 2019 ​ basin ​ metallurgical ​ thermal ​ other ​ consolidated ( in thousands ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gaap revenues in the condensed consolidated statements of operations ​ $ 915,750 ​ $ 990,550 ​ $ 377,202 ​ $ 10,850 ​ $ 2,294,352 less : adjustments to reconcile to non-gaap segment coal sales revenue ​ ​ ​ ​ ​ coal risk management derivative settlements classified in `` other income `` ​ — ​ ( 1,122 ) ​ ( 6,782 ) ​ — ​ ( 7,904 ) coal sales revenues from idled or otherwise disposed operations not included in segments ​ — ​ — ​ — ​ 10,820 ​ 10,820 transportation costs ​ 15,079 ​ 173,352 ​ 90,151 ​ 30 ​ 278,612 non-gaap segment coal sales revenues ​ $ 900,671 ​ $ 818,320 ​ $ 293,833 ​ — ​ $ 2,012,824 tons sold ​ 74,531 ​ 7,769 ​ 7,717 ​ ​ coal sales per ton sold ​ $ 12.08 ​ $ 105.33 ​ $ 38.07 ​ ​ ​ ​ ​ 68 non-gaap segment cash cost per ton sold non-gaap segment cash cost per ton sold is calculated as segment cash cost of coal sales divided by segment tons sold . segment cash cost of coal sales is adjusted for transportation costs , and may be adjusted for other items that , due to generally accepted accounting principles , are classified in “ other income ” on the consolidated income statements , but relate directly to the costs incurred to

cash cost per ton sold ​ $ 10.63 ​ $ 66.07 ​ $ 32.85 ​ ​ ​ ​ ​ 69 reconciliation of segment adjusted ebitda to net income ( loss ) the discussion in “ results of operations ” above includes references to our adjusted ebitda for each of our reportable segments . adjusted ebitda is defined as net income ( loss ) attributable to the company before the effect of net interest expense , income taxes , depreciation , depletion and amortization , the amortization of sales contracts , and the accretion on asset retirement obligations . adjusted ebitda may also be adjusted for items that may not reflect the trend of future results by excluding transactions that are not indicative of our core operating performance . we use adjusted ebitda to measure the operating performance of our segments and allocate resources to our segments . adjusted ebitda is not a measure of financial performance in accordance with generally accepted accounting principles , and items excluded from adjusted ebitda are significant in understanding and assessing our financial condition . therefore , adjusted ebitda should not be considered in isolation , nor as an alternative to net income ( loss ) , income ( loss ) from operations , cash flows from operations or as a measure of our profitability , liquidity or performance under generally accepted accounting principles . investors should be aware that our presentation of adjusted ebitda may not be comparable to similarly titled measures used by other companies . the table below shows how we calculate adjusted ebitda . replace_table_token_11_th ​ o ther includes primarily income from our equity investments , certain changes in the fair value of coal derivatives and coal trading activities , certain changes in fair value of heating oil derivatives we use to manage our exposure to diesel fuel pricing , net ebitda provided by our land company , and certain miscellaneous revenue . for the year ended december 31 , 2020 , amounts included in other decreased ebitda by approximately $ 3.4 million versus increasing ebitda approximately $ 14.5 million in the year ended december 31 , 2019. the decrease in ebitda was primarily related to unfavorable change in value of coal derivatives of approximately $ 16.4


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```cash cost per ton sold ​ $ 10.63 ​ $ 66.07 ​ $ 32.85 ​ ​ ​ ​ ​ 69 reconciliation of segment adjusted ebitda to net income ( loss ) the discussion in “ results of operations ” above includes references to our adjusted ebitda for each of our reportable segments . adjusted ebitda is defined as net income ( loss ) attributable to the company before the effect of net interest expense , income taxes , depreciation , depletion and amortization , the amortization of sales contracts , and the accretion on asset retirement obligations . adjusted ebitda may also be adjusted for items that may not reflect the trend of future results by excluding transactions that are not indicative of our core operating performance . we use adjusted ebitda to measure the operating performance of our segments and allocate resources to our segments . adjusted ebitda is not a measure of financial performance in accordance with generally accepted accounting principles , and items excluded from adjusted ebitda are significant in understanding and assessing our financial condition . therefore , adjusted ebitda should not be considered in isolation , nor as an alternative to net income ( loss ) , income ( loss ) from operations , cash flows from operations or as a measure of our profitability , liquidity or performance under generally accepted accounting principles . investors should be aware that our presentation of adjusted ebitda may not be comparable to similarly titled measures used by other companies . the table below shows how we calculate adjusted ebitda . replace_table_token_11_th ​ o ther includes primarily income from our equity investments , certain changes in the fair value of coal derivatives and coal trading activities , certain changes in fair value of heating oil derivatives we use to manage our exposure to diesel fuel pricing , net ebitda provided by our land company , and certain miscellaneous revenue . for the year ended december 31 , 2020 , amounts included in other decreased ebitda by approximately $ 3.4 million versus increasing ebitda approximately $ 14.5 million in the year ended december 31 , 2019. the decrease in ebitda was primarily related to unfavorable change in value of coal derivatives of approximately $ 16.4
```    
 Suspicious Activity Report : the initial industrial shutdowns , particularly in the automotive and oil and gas sectors , that drove significant reductions in steel demand and the idling of multiple blast furnaces globally , began to reverse in the third quarter of 2020 , leading to increasing steel demand and the restarting of many idled blast furnaces . in particular , domestic auto production returned to pre-shutdown levels in july , but has declined slightly since . the return of industrial production to pre-pandemic levels has been , and will continue to be uneven ; for example , oil and gas drilling activity , although increasing slowly , remains significantly depressed as compared to pre-pandemic levels . the return of overall industrial production to pre-covid-19 levels is also likely to be lengthy and , as we have seen in the fourth quarter of 2020 , is subject to setbacks should covid-19 become resurgent . during 2020 , demand destruction elicited a supply side response , as significant high cost coking coal mine idlings and slowdowns were announced in north america and globally . the overall production volume removed from the markets this year is significant . while some of the curtailed production has returned or can return to the market with the right price signal , we believe that the cash cost of a 60 significant portion of the currently curtailed coking coal production exceeds current prompt pricing . to date , due to our low cost structure , we have avoided idling any of our coking coal operations . longer term , we believe continued limited global capital investment in new coking coal production capacity , economic pressure on higher cost production sources , and production responses to the covid-19 pandemic will provide support to coking coal markets as demand continues to return to the steel production supply chain . during the fourth quarter of 2020 , a major trade dispute escalated between china , a major importer of coking coal , and australia , the world 's largest exporter of coking coal . specifically , china has effectively banned the import of coking coal from australia . this disrupted historical trade patterns , and led to pricing anomalies in the international coking coal markets . through most of the fourth quarter of the year ended december 31 , 2020 , the prompt index price for united states east coast high-vol a ( hva ) , our main product , low-vol ( lv ) , and even high-vol b ( hvb ) coking coal exceeded the prompt index price for australian east coast premium low volatile ( plv ) coking coal . recently the plv index has rapidly risen significantly , returning to a more historically normal price relationship between products . uncertainty and volatility in pricing and pricing relationships are likely until the larger trade dispute between china and australia is settled . while most of our committed but unpriced coking coal volume is linked to the united states east coast hva , lv , or hvb indexes , we do have approximately 1.1 million tons of committed but unpriced coking coal linked to the plv or other asia/pacific indexes for 2021. demand for domestic thermal coal remained significantly below the prior year due to historically low natural gas prices , covid-19 related commercial and industrial demand declines and the continued increase in subsidized renewable generation sources , particularly wind . natural gas pricing recovered in the second half of 2020 from historically low levels seen in the first half of 2020 , and as a result coal fired generation , particularly powder river basin fired generation , was competitive in many regions of the country during the second half of the year . production levels of natural gas were below the prior year 's levels , but storage levels remained significantly above last year 's levels . additionally , generator coal stockpiles declined during the second half of 2020 , but remain above historical averages based on days of burn . international thermal coal market pricing that had remained at levels that were uneconomic for all of our thermal operations for most of the year , increased significantly late in the year . by late december prompt international thermal coal pricing reached levels that can support economic exports from our west elk operation . similar to metallurgical markets discussed above , actions taken to combat the spread of covid-19 across many regions of the national and global economy continue to negatively impact thermal coal demand and supply . as a result , we expect domestic and global thermal markets to remain challenged . on september 29 , 2020 , the u.s. district court ruled against our proposed joint venture with peabody energy corporation that would have combined our powder river basin and colorado mining operations with peabody 's . following the ruling , we announced the termination of our joint venture efforts due to the significant investment of time and resources that would be required to conduct an appeal . in light of the unfavorable ruling and decision to terminate efforts on the joint venture , we continue to pursue other strategic alternatives for our thermal assets . these alternatives include , among other things , potential divestiture . we also continue to evaluate opportunities to shrink our operational footprint at those mines , reduce their asset retirement obligations , and establish self-funding mechanisms to address those long-term liabilities . in alignment with our desire to shrink our operational footprint and associated liabilities , we have committed to closing our coal creek operation in the powder river basin once all currently committed sales have been shipped by the end of 2022 or sooner . story_separator_special_tag longwall operations accounted for approximately 60 % of our shipment volume in the year ended december 31 , 2020 and 71 % of our shipment volume in the prior year . other thermal — adjusted ebitda for the year ended december 31 , 2020 declined from the year ended december 31 , 2019 due to reduced sales volume , lower pricing , and increased cash cost per ton sold . all of these metrics are impacted by the inclusion in the year ended december 31 , 2019 of our former coal-mac operation , which was sold in december 2019. coal-mac provided approximately 2.1 million tons sold in the year ended december 31 , 2019. tons sold from ongoing operations declined approximately 2.2 million tons in the year ended december 31 , 2020 , as low natural gas pricing , increased renewable generation , and uneconomic international pricing impacted volume . in addition , in late march of 2020 we temporarily idled our viper mine due to nonperformance of the mine 's primary customer . the customer restarted deliveries in early may , and we reopened the mine at approximately the same time . in late december of 2020 , prompt international thermal coal pricing increased to levels that can support economic exports from our west elk operation but the international thermal coal pricing is volatile . on december 31 , 2020 , we sold our other thermal operation , viper , to knight hawk holdings , llc . for further information on the sale of viper , please see note 4 , “ divestitures ” to the consolidated financial statements . in december of the year ended december 31 , 2019 , we sold our other thermal operation , coal-mac llc , to condor holdings llc . for further information on the sale of coal-mac llc , please see note 4 , “ divestitures ” to the consolidated financial statements . ​ 67 ​ reconciliation of non-gaap measures non-gaap segment coal sales per ton sold non-gaap segment coal sales per ton sold is calculated as segment coal sales revenues divided by segment tons sold . segment coal sales revenues are adjusted for transportation costs , and may be adjusted for other items that , due to generally accepted accounting principles , are classified in “ other income ” on the consolidated income statements , but relate to price protection on the sale of coal . segment coal sales per ton sold is not a measure of financial performance in accordance with generally accepted accounting principles . we believe segment coal sales per ton sold provides useful information to investors as it better reflects our revenue for the quality of coal sold and our operating results by including all income from coal sales . the adjustments made to arrive at these measures are significant in understanding and assessing our financial condition . therefore , segment coal sales revenues should not be considered in isolation , nor as an alternative to coal sales revenues under generally accepted accounting principles . ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ powder river ​ ​ other idle and ​ ​ year ended december 31 , 2020 ​ basin ​ metallurgical ​ thermal ​ other ​ consolidated ( in thousands ) ​ ​ ​ ​ ​ gaap revenues in the condensed consolidated statements of operations ​ $ 662,135 ​ $ 641,536 ​ $ 139,497 ​ $ 24,424 ​ $ 1,467,592 less : adjustments to reconcile to non-gaap segment coal sales revenue ​ ​ ​ ​ ​ coal risk management derivative settlements classified in `` other income `` ​ — ​ ( 577 ) ​ ( 8,632 ) ​ — ​ ( 9,209 ) coal sales revenues from idled or otherwise disposed operations not included in segments ​ — ​ — ​ — ​ 24,322 ​ 24,322 transportation costs ​ 13,625 ​ 124,494 ​ 41,852 ​ 102 ​ 180,073 non-gaap segment coal sales revenues ​ $ 648,510 ​ $ 517,619 ​ $ 106,277 ​ $ — ​ $ 1,272,406 tons sold ​ 52,366 ​ 6,979 ​ 3,356 ​ ​ coal sales per ton sold ​ $ 12.38 ​ $ 74.17 ​ $ 31.67 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ powder river ​ ​ other idle and ​ ​ year ended december 31 , 2019 ​ basin ​ metallurgical ​ thermal ​ other ​ consolidated ( in thousands ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gaap revenues in the condensed consolidated statements of operations ​ $ 915,750 ​ $ 990,550 ​ $ 377,202 ​ $ 10,850 ​ $ 2,294,352 less : adjustments to reconcile to non-gaap segment coal sales revenue ​ ​ ​ ​ ​ coal risk management derivative settlements classified in `` other income `` ​ — ​ ( 1,122 ) ​ ( 6,782 ) ​ — ​ ( 7,904 ) coal sales revenues from idled or otherwise disposed operations not included in segments ​ — ​ — ​ — ​ 10,820 ​ 10,820 transportation costs ​ 15,079 ​ 173,352 ​ 90,151 ​ 30 ​ 278,612 non-gaap segment coal sales revenues ​ $ 900,671 ​ $ 818,320 ​ $ 293,833 ​ — ​ $ 2,012,824 tons sold ​ 74,531 ​ 7,769 ​ 7,717 ​ ​ coal sales per ton sold ​ $ 12.08 ​ $ 105.33 ​ $ 38.07 ​ ​ ​ ​ ​ 68 non-gaap segment cash cost per ton sold non-gaap segment cash cost per ton sold is calculated as segment cash cost of coal sales divided by segment tons sold . segment cash cost of coal sales is adjusted for transportation costs , and may be adjusted for other items that , due to generally accepted accounting principles , are classified in “ other income ” on the consolidated income statements , but relate directly to the costs incurred to

