Hello, this is Tanaka. Let me express my sincere gratitude to our shareholders and investors for their support and advice on the business activities of Eanos Group. Let me start my presentation on the Q3 financial results and the full year outlook. Slide 3 shows our operating income excluding inventory valuation for the Q3 of fiscal year 2020. That is JPY 160,900,000,000 down JPY 111,300,000,000 year on year.
As shown here, the deterioration was mainly due to COVID-nineteen, which caused lower sales of petroleum products, lower profits of oil and natural gas E and P due to sluggish crude oil prices and lower production output at the Casarona's copper mine in Chile due to manpower restraints. Other negative factors included an impairment loss at the Casarona's copper mine due to a revised mining plan in light of the pandemic and a one time loss associated with the shutdown and the relocation of the joint venture with PetroChina International Japan from the Osaka refinery to the Chiba refinery. On the other hand, positive factors included a steady growth in domestic petroleum product margins, increased sales of electronic materials due to increased demand for telecommunications for telework and lower operating expenses. Next Slide 4 shows an overview of the full year forecast for fiscal 2020. The forecast remains unchanged from the previous announcement.
We will maintain our forecast of 190,000,000,000 yen in operating income, excluding inventory valuation and 200,000,000,000 yen including inventory valuation. The main factors are, as mentioned here, impairment loss of 70,000,000,000 yen at the Casaronas copper mine, gain on extinguishment of debt of 60,000,000,000 yen due to the additional interest acquired in Casarona's from Mitsui Mining and Smelting and Mitsui and Company and loss of about 20,000,000,000 yen due to a sharp rise in JEPX prices and 4, the favorable domestic petroleum product margins, loss from the consolidation and closure of the Negishi refinery and Chita refinery and increased sales of electronic materials due to increased telecommunications demand making the forecast unchanged from the previous announcement. There is no change in our shareholder return policy of distributing stable dividends of not less than 22 yen per share per year and maintaining a total return ratio of at least 50% of net income, excluding inventory effects over the 3 year period. Next, Slide 5 illustrates the impairment loss and the gain on extinguishment of debt of the Kessaronas copper mine. As shown on the upper part of the slide, the Kessaronas copper mine recorded an impairment loss of 69,400,000,000 yen in the 3rd quarter.
The mine was continuing to operate while implementing measures to prevent the spread of infections such as limiting the number of people entering into the mine. However, due to the significant delays in exploration, we have decided to reverse the mining plan. The revisions as shown below are mainly due to the pandemic and they include correction of the mining pit slope in consideration of safety, review of operating parameters such as crude or quality, lower processing volume due to a decreased groundwater intake caused by insufficient snowfall. On the other hand, on the Q4, we expect to record a gain on debt extinguishment of approximately 60,000,000,000 yen also related to Katsaronis copper mine, as shown in the lower part of the table. The gain of 60,000,000,000 yen on a consolidated basis is due to the acquisition of loans at a price lower than the book value as we acquired the entire interest in the Casarones from Mitsui Mining and Smelting and Mitsui and the company.
This will be recognized as other income in Q4. Next Slide 6 shows the trends of JEPX or domestic electricity spot prices. Until December, due to the low wholesale prices and low refinery utilization amid the COVID-nineteen pandemic, we reduced power generation at our own refineries and procured power from the market. Under such circumstances, the price of JEPX surged due to the cold winter season, which started in mid December. In order to reduce the purchase of electricity from the wholesale market, we took measures to increase the amount of electricity generated at our own refineries, but it took time to secure raw materials and restart the power generation facilities.
And as a result, we expect to incur a loss of approximately JPY 20,000,000,000 in January. At present, the trend of JEPX has calmed down, but in preparation for another price hike, we are formulating countermeasures such as direct contracts with sellers and ways to flexibly secure raw materials for power generation. Next, I will explain the progress of refinery and plant restructuring. With regard to the reduction of refining capacity, since the previous announcement, we have newly decided to shut down part of the crude oil processing facilities at the Negishi refinery in January 2022. This will reduce our crude processing capacity by approximately 10% or 180,000 barrels per day compared to April 2017 when JX and Tonen General marched.
We will continue to implement our supply chain transformation. Next Slide 8 summarizes the current business environment. Crude oil prices remained at a low level compared to the same period last year due to COVID-nineteen other factors. However, the prices turned firm recently due to expected price recovery following a resumption of economic activities and coordinated production cuts by oil producing countries. Copper prices also weakened from the previous fiscal year to the beginning of the current fiscal year due to COVID-nineteen, but have risen significantly since May due to the recovery in China and the concern over supply shortage in Chile and other major producing countries where the number of COVID-nineteen cases is rising.
As shown in the left graph on Page 9, Petroleum product margins have been higher than in the previous year, partly due to the positive time lag caused by the recovery phase of crude oil prices. As for the right graph, Park Slane margins have been recovering slightly due to expectations for the start of new PTA equipment, but they have remained sluggish due to concerns about increased supply in China and easing of demand supply as well as the impact of COVID-nineteen. Next, I will explain the year on year comparison of the 3rd quarter results on Page 11 onward. Operating income for Q3 FY 2020 was 133,800,000,000 yen. Inventory impact was 27,100,000,000 yen excluding which operating income was 160,900,000,000 yen down 111,300,000,000 yen from the same period last year.
Net income attributable to owners of the parent decreased 57,600,000,000 yen to 67,000,000,000 yen from the same period last year. I will discuss the breakdown of operating income by segment using waterfall charts on next several slides. Slide 13 is for the Energy segment. Operating income excluding inventory valuation was down 34,000,000,000 yen to 116,400,000,000 yen. From the left, Pretorian Products is up 23,800,000,000 yen which is broken down to sales volume of minus 51,500,000,000 yen due to the lower domestic and overseas demand amid the pandemic and the margins of positive 75,300,000,000 yen due to time lag, cost reduction and other factors.
This includes a one time loss of 27,900,000,000 yen associated with the restructuring of the Osaka and Ochiba refineries. Petrochem Coals was down 21,300,000,000 yen due to reduced sales volumes and the paraxylene and margin deterioration. Materials is down 36,800,000,000 yen mainly due to a decrease in needle coke volume. Slide 14 shows Oil and Natural Gas E and P operating income, which is down 33,500,000,000 yen year on year to 6,600,000,000 yen mainly due to the lower oil prices. Despite the full contribution of the UK North Sea, Marina Oilfield and the Killeen Gas Field, which came online last year and an increased sales volume due to the newly started production of the Rayyan oil and gas field in Malaysia.
The deterioration in expansion of other was due to the operating expenses for new oil fields. Slide 15, Metal segment. From the left, Functional Materials, Thin Film Materials and others is up 9,800,000,000 yen due to an increase in sales volumes, driven by growing data communication demand. In mineral resources, as mentioned earlier, an impairment loss of 69,400,000,000 yen was recorded at the Katsuranes copper mine. On the other hand, although there was an improvement of 23,400,000,000 yen due to the rising copper price from 2.18 at the beginning of the year to 3.51 yen at the end of the year, The increase was limited to 7,800,000,000 yen due to production cutbacks at Casaaronas to mitigate the impact of COVID-nineteen as well as a higher Chilean peso.
Mineral Resources as a whole declined 61,600,000,000 yen including impairment losses. Smelting and Recycling is down 1,100,000,000 yen due to lower sulfuric acid prices despite higher precious metal prices. Non allocated corporate expenses and others is down 2,900,000,000 yen due to the elimination of consolidated internal transactions and other factors. Next, please refer to Page 16 for the balance sheet and cash flow statement. Consolidated cash flow is shown to the right.
I will discuss the figures after the repayment of lease liabilities. Operating cash flow for Q3 was JPY484,900,000,000, including operating income of JPY 160,900,000,000, excluding inventory valuation, JPY 185,500,000,000 in depreciation and amortization and JPY 138,500,000,000 in other changes. Cash flow from investing activities was a net outflow of 226,100,000,000 yen resulting in a net inflow of 258,800,000,000 yen in free cash flow. The balance sheet is shown to the left. Net interest bearing debt, excluding cash on hand, was 1,681,000,000,000 yen at the end of December.
The equity ratio attributable to owners of the parent was 28.4 percent. And the net DE ratio was 0.63 times. I will skip the reference materials on Page 17 onwards. Thank you very much for your kind attention.