UPDATE 3-Brazil state says makes big iron ore find

* Mato Grosso state find seen with 11.5 bln tns iron ore

* Deposit seen with 41 pct iron content in ore

* Owner of deposit named as GME4

(Adds Vale comment on size of Carajas deposit)

CUIABA, Brazil, Sept 1 (Reuters) - Brazil's Mato Grosso state government said on Wednesday it had registered a major mineral deposit discovery with an estimated 11.5 billion tonnes of iron ore of a 41 percent Fe grade.

If confirmed it would be bigger than the country's massive Carajas iron ore mine in Para state, which the national mining department estimates at 2 billion to 3 billion tonnes of ore. Brazilian mining giant Vale, which controls Carajas, says it holds 7 billion tonnes of ore.

Although Carajas is smaller than the Mato Grosso deposit, it has relatively high ore grades of 67 percent iron content.

The Mato Grosso state government named the concession holder of the deposit as GME4 of Global Mine Exploration.

The logistics of developing the mine will be challenging. The center-west state of Mato Grosso is deep in the interior of Brazil and far from any ports. A railway or a river barge system would need to be developed to get any eventual production to the international market.

China has been the main buyer of the 23 million to 25 million tonnes of iron ore that Brazil exports monthly, with Vale accounting for the majority of those shipments. (Graphic: link.reuters.com/cef77m ) (Reporting by Jonas da Silva; writing by Reese Ewing; Editing by David Gregorio)