Newmont submitted what the gold mining giant has labelled as its best and final offer to Newcrest on April 10, sweetening the deal to US$19.5 billion.

If Newcrest accepts the boosted bid, the deal would be the largest gold mining takeover in history and Newcrest’s portfolio would combine its gold and copper exposure to add nearly 50 billion pounds of copper reserves and resources to Newmont’s asset base. Newmont would also acquire Newcrest’s Red Chris and Brucejack gold mines, both of which are located north of Vancouver, as reported by the Financial Post.

In February, Newcrest rejected Newmont’s earlier takeover bid of US$17 billion, saying that it did not offer sufficient value to its shareholders.

Related: Glencore has made a revised offer for the acquisition of Teck Resources, after its initial merger proposal was rejected last week

Newcrest has granted Newmont access to its books for confirmatory due diligence, which is expected to take about four weeks.

The revised proposal offers Newcrest shareholders 0.4 shares in Newmont for each Newcrest share held, an increase on the 0.38 shares it offered in its February proposal, and Newcrest shareholders would own about 31 per cent of the combined company. Newcrest would also be able to fund and pay its shareholders a special dividend of up to US$1.10 per Newcrest share.

“We are entering a new era in which mining companies must hold themselves to a higher standard of sustainability and long-term value creation,” said Tom Palmer, president and CEO of Newmont, in a news release on April 11. “This transaction would strengthen our position as the world’s leading gold company by joining two of the sector’s top senior gold producers and setting the new standard in safe, profitable and responsible mining. Together as the clear gold-mining leader, we would be well-positioned to generate strong, stable and lasting returns with best-in-class sustainability performance for decades to come.”

According to Newmont, the proposed combination with Newcrest would create “the industry’s best portfolio of world-class assets with the highest concentration of top-tier operations, primarily in favourable, low-risk mining jurisdictions.”