Engineering firm Monadelphous Group has signed new contracts with resources firms including Rio Tinto and Xstrata worth around $230 million.

Monadelphous said the contracts related to six separate projects in the mining, energy and infrastructure sectors.

Included is structural, mechanical, piping, electrical and instrumentation works for the upgrade of the coal preparation plant and stockyards at Rio Tinto’s Kestrel coal mine near Emerald in Queensland.

Under another contract, Monadelphous will carry out structural and mechanical works on the coarse ore stockpile at Rio Tinto’s Cape Lambert iron ore project in Western Australia.

Monadelphous will also construct and commission coal conveyors associated with Xstrata Coal’s Ulan West Project in the NSW central west.

The remaining contracts relate to wastewater infrastructure projects in Toowoomba in Queensland, construction of an onshore gas pipeline associated with Chevron’s Gorgon LNG project in WA, and an extension to an existing contract for maintenance and shutdown services at ConocoPhillips’ Darwin LNG facility.

All of the construction contracts for scheduled for completion in the second half of calendar 2012, Monadelphous said.