* Investors cautious ahead of key UK, U.S. data

* Weak miners weigh

* Banks rally after recent sell-offs

By Jon Hopkins

LONDON, 9 Jan (Reuters) - Britain's top share index .FTSE was 0.3 percent lower in early trade on Friday with weak miners weighing and investors cautious ahead of some key economic data due later, notably the U.S. December jobs report.

By 0858 GMT, the FTSE 100 index was 13.70 points firmer at 4,491.67 after shedding 2.14 points in the previous session in the wake of a 50 basis point cut in UK interest rates.

Weakness in heavyweight mining issues dented blue chip sentiment once again although metal prices showed some recovery on Friday, reflecting uncertainties over the global economic picture.

Xstrata (XTA.L: Quote, Profile, Research), Vedanta Resources (VED.L: Quote, Profile, Research), Anglo American (AAL.L: Quote, Profile, Research), Kazakhmys (KAZ.L: Quote, Profile, Research) and Eurasian Natural Resources (ENRC.L: Quote, Profile, Research) lost between 0.8 and 5.3 percent.