With Rio Tinto Limited (ASX: RIO) aggressively expanding its mining operations in order to maximise output and reduce costs, some investors may be wondering if Rio’s ore resources can continue to support such a rapid expansion.

The answer is yes, they can, with 2014 delivering massive increases in ore reserves across the board compared to 2013, and discovery shows no signs of slowing down.

Updates on diamond, iron ore, and coal reserves (but not copper) were provided to the market late on Friday, and investors can rest easy that Rio’s mining can continue unhindered.

Here’s what you need to know:

• Canadian Diavik diamond project reserves (proved and probable) increased to 18.1 million tonnes (Mt), at an average of 2.9 carats per tonne (c/t)

• Hail Creek coal mine in Queensland reserves increased by 25Mt to a total of 85Mt

• And the main show, Hamersley Iron Brockman in the Pilbara in WA, saw its iron ore reserves increase by 681Mt to 2,998Mt

• Brockman process iron ore increased by 324Mt to 1,137Mt

• Two additional reserves, Yandicoogina Braid (included in Brockman process figures) and Robe Joint-Venture Channel Iron Deposit (677Mt) were also added to Rio’s total reserves

As readers can see, Rio has zero risk of running out of iron ore any time soon.

At current targeted production rates (once the expansion is completed) of 320Mt per annum, Rio has a comfortable 10 years of production remaining and plenty of room to expand both its production and its reserves through further exploration.

The Hail Creek and Diavik projects also have plenty of life left in them, although unfortunately the outlook for coal is just as bad as iron ore, with many Aussie producers losing money on their product.

Despite its expanded reserves, it’s still uncertain if Rio has what it takes to beat BHP Billiton Limited (ASX: BHP) in the growing shareholder earnings field over the coming years.

It’s even more uncertain whether smaller iron ore miners can continue to compete in a market so firmly under the thumb of global players, who seem determined to drive prices into the ground.

The resources sector might be too risky for a lot of investors, but if you had to own one company I would make it either Rio Tinto, or BHP.