Our earnings of $5.04 per share surpassed our previous earnings per share record set last quarter, our first half earnings of $8.13 per share exceeds our full year earnings per share record of $7.42 set in 2018.
Our new greenhouse gas reduction commitment will take our carbon intensity down to 77% below today's world average.
Our commitment is to reduce our Scope 1 and 2 greenhouse gas emissions intensity by a combined 35%.
Our performance today is what many of our competitors around the globe are aspiring to achieve by 2030, '40, '50 and beyond.
Federal infrastructure spending plans currently under consideration are expected to increase U.S. steel demand by as much as 5 million tons per year for every $100 billion of new investment.
Second quarter earnings of $5.04 per diluted share exceeded our guidance range.
In the second quarter, the Hickman specialty cold mill ran at 118% of rated capacity, more than double its originally projected production ramp timeline.
Since beginning operations in mid-2019, this project's life-to-date profitability also substantially exceeds its initial forecast, and the Hickman team is looking ahead to further expanding long-term earnings power as it begins the work of commissioning its third-generation flexible galvanizing line equipment.
At the close of the second quarter, our cash, short-term investments, and restricted cash holdings totaled $3.2 billion.
Compared with the end of the first quarter position, our second quarter cash position increased by about $226 million.
That increase is after funding share repurchases of $614 million, cash dividends of $123 million, capital expenditures of $389 million and a working capital expansion on the inventory receivables and payables line items totaling about $945 million.
Nucor's liquidity also includes our undrawn $1.5 billion unsecured revolving credit facility, which does not mature until April of 2023.
Total long-term debt including the current portion was approximately $5.3 billion at quarter-end.
Gross debt as a percent of total capital was approximately 30%, while net debt was 12% of total capital and remains well below our targeted range of 18% to 23%.
We expect that these businesses, along with the numerous internal growth projects we have been executing on, will materially add to Nucor's earnings and cash flow generation in the years ahead.
Cash provided by operating activities for the first half of 2021 was $1.9 billion.
Nucor's free cash flow or cash provided by operations minus capital spending was $1.2 billion.
We now estimate total year capital spending of approximately $1.8 billion.
Each of our three most significant capital projects, the expansion and modernization of the Gallatin, Kentucky sheet mill, the Generation 3 flexible galvanizing line at the Hickman, Arkansas sheet mill, and the greenfield Brandenburg, Kentucky plate mill remain on schedule.
During the second quarter, we continue to see attractive value in our shares repurchasing 6.765 million shares at an average cost of approximately $91 per share.
Over the first half of this year, Nucor share repurchases totaled more than 12 million shares at an average cost of about $75 per share.
Shares outstanding have been reduced by approximately 3% from the year-end 2020 level.
For the first half of 2021, total cash returned to shareholders through dividends, and share repurchases totaled just under $1.2 billion representing approximately 47% of net earnings for the period.
As we have said previously, we intend to return a minimum of 40% of our net income to Nucor shareholders.
We expect earnings in the third quarter of 2021 to again set a new record.
Compared to the second quarter, we expect earnings growth at all three of our segments, most notably our Steel mills segment.
Nucor's record results highlight the success of our 27,000 team members building a stronger and more profitable Nucor.

Summary:
Our earnings of $5.04 per share surpassed our previous earnings per share record set last quarter, our first half earnings of $8.13 per share exceeds our full year earnings per share record of $7.42 set in 2018.
Second quarter earnings of $5.04 per diluted share exceeded our guidance range.
Since beginning operations in mid-2019, this project's life-to-date profitability also substantially exceeds its initial forecast, and the Hickman team is looking ahead to further expanding long-term earnings power as it begins the work of commissioning its third-generation flexible galvanizing line equipment.
We expect that these businesses, along with the numerous internal growth projects we have been executing on, will materially add to Nucor's earnings and cash flow generation in the years ahead.
We expect earnings in the third quarter of 2021 to again set a new record.
Compared to the second quarter, we expect earnings growth at all three of our segments, most notably our Steel mills segment.