Are you talking about mining silver and gold? If so at level 20 gold will be hard to get as the creatures in the zone will argo your level not to say it can't be done.
My favorite silver mining spot is n of bree or barrow downs. To get to the mining nodes n of bree follow the road to tressel bridge go rt up the hill before you enter the valley to get to the little town before tressel bridge.
Once on top of the hill before the town follow the left zone wall staying to the rt of the cliff. You'll see plenty of silver with a ton of barrow ore. (Yew plants also spawn in this area. Easy to make a toon to make yellow dyes to color your armor a golden yellow color. Looks pretty good too alot better than running around with a miss match of colored armor.)
To hunt gold I like to go over the last bridge into the trollshaws go rt follow mining points you'll get gold and dwarf iorn.
I always look for other miners if you need ore to craft weapons and armor you'll have silver, gold, and MM silver that is used for jewelry trade. If your a jewler you'll have ore weapon and armor makers need. I always save in stacks of 50 and trade my ore to others.
I would still be mining mm silver trying to get to grandmaster in jewlrey if I didn't do these trades. Having achieved grandmaster in jewlrey I am now trying to reach grandmaster in weapon making and am trading silver, gold, and platt for iorn. Still hanging on to mm silver drops too hard to trade away.