Anglo American has reported a 45 per cent increase in annual earnings, halved its net debt and claimed to be 'fundamentally different' from during the commodity downturn in its latest results.The mining company's underlying earnings before tax hit £6.3 billion in 2017 its preliminary results revealed on Thursday, a 45 per cent increase year-on-year.It also delivered free cash flow of £3.5 billion, a 93 per cent increase, which helped to cut debt by almost half last year.It has also restored dividends that were scrapped during the 2015/16 downturn with shareholders due to receive a slice of £2.3 billion worth of profits.At the height of the commodity crash just over two years ago, Anglo American said it would greatly reduce its activities to focus on diamonds, platinum group metals and copper.As the market improved, it said it was no longer a forced seller, but it has reduced its assets by 47 percent since 2012, while greatly increasing productivity.'Very simply put, we have done what we said we would do,' boss Mark Cutifani told reporters on a conference call.He said that most important of all was the improvement in productivity, which rose 28 percent per person last year alone.'Anglo American is a fundamentally different business. We are more resilient. We are more competitive. We are delivering solid returns,' he said. 'Our intention is to keep improving the business from the base we have established today.'Anglo shares, which had risen more than 15 per cent this year and outperformed rivals, fell nearly 4 percent on Thursday morning as analysts said Thursday's results were vastly improved but missed some forecasts.It recovered some ground as the day wore on but remained 2.8 per cent lower at 11am GMT.All the major miners have recovered from the crash of 2015-16. Over the past two weeks, they have announced increased returns for shareholders and lower debt, while promising to avoid the spending sprees that contributed to the end of the previous boom.Anglo American and Glencore -- which on Wednesday announced results it said were the strongest yet -- fell the furthest and have also rallied the most as commodity markets have recovered.South African-focused Anglo has this year received a further spur from expectations that new President Cyril Ramaphosa will support the industry.Edward Sterck, analyst at BMO Capital Markets, which rates Anglo outperform, said the full-year profit was slightly light.'Overall, the results are a little disappointing, but the company has demonstrated a significant year-on-year improvement and is clearly still walking down the path to redemption,' he wrote.One headwind for Anglo American is a strengthened South African rand, which has reached three-year highs, as a result of the replacement of Jacob Zuma by Ramaphosa.A stronger rand versus the dollar increases costs for South African-based operations, although it is offset by higher commodity prices.