Swiss multinational Glencore has sweetened its offer for Canadian miner Teck Resources, introducing a cash element to entice those investors that prefer a full exit from coal.

In a letter addressed to Teck chairperson Sheila Murray and CEO Jonathan Price, Glencore CEO Gary Nagle said the commodities giant would offer shareholders 24% of the combined metals-focused business (MetalsCo) and $8.2-billion in cash.

The initial offer, which was valued at about $22.5-billion, includes a plan to buy the Canadian miner and then spin off the coal assets, creating two standalone businesses, MetalsCo and CoalCo.

"Glencore continues to believe that CoalCo's combined thermal and coking coal assets would position it as a leading, highly cash-generative bulk commodity company which would attract strong investor demand given its yield potential. However, we acknowledge that certain of your investors may prefer a full coal exit and others may not desire thermal coal exposure," Nagle said.

Teck, for its part, is planning a restructuring in which it would spin off its steelmaking coal unit to focus on copper and other industrial metals. In an investor call on Monday, Price reinforced Teck's rejection of the unsolicited offer, telling shareholders its restructuring plan was the only viable option.

Teck stated on Tuesday that Glencore’s revised proposal appeared to be largely unchanged, with the exception of a cash consideration alternative in lieu of shares in the proposed combined coal entity.

"The revised proposal does not provide an increase in the overall value to be received by Teck shareholders or appear to address material risks previously raised by Teck," the Canadian miner said.

Teck stated that Glencore's proposal was not actionable and not in the best interests of Teck or its shareholders. The board determined that the previously rejected Glencore proposal would have exposed Teck shareholders to material risks and uncertainty and would have transferred significant value to Glencore at the expense of Teck shareholders.