Coates, a centre-back, signed for the club back in November from Premier Division side Ashton United. Since then, he has made 20 appearances for the club. He was sent off during their 2-0 defeat at Dunston. In total, he received 10 yellow cards.
Meanwhile, Robson, a midfielder, signed for the club back in October from Belper Town. Since his arrival, he has made 25 appearances for the club. He was also sent off in that 2-0 defeat against Dunston.
Both will be hoping to steer the Ramicorns to another season at step four.
The club have also announced the signing of Corey Gregory, who rejoins the club from Brighouse Town.
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