(ShareCast News) - Rio Tinto has launched a $3bn bond-buyback plan as the miner looks to use its put its cash to use. Following its $4.5bn buybacks earlier in 2016, Rio Tinto has offered for redemption roughly $1.5bn of its 2017 and 2018 US dollar-denominated notes and begun cash tender offers to purchase up to approximately $1.5bn of its 2019, 2020, 2021 and 2022 notes.In April, the FTSE 100 group bought $1.5bn of its 2017 and 2018 notes and in June purchased $3bn of its 2018, 2020, 2021 and 2022 notes.