Mars peroxide

The availability of hydrogen peroxide in Martian soil won't be high 
enough to mine it. If the hypothetical production is dependent on water 
vapor, it will be extremely scarce. The amount that accumulates will 
level off at some minute contamination percent as (wind driven) motion 
of upper dust layers exposes the peroxide to solar UV and it breaks 
down. If the accumulation is large enough to produce the results seen in 
Viking experiments, we can set a lower limit to peroxide percent. 1% was 
mentioned. At that level how much soil would we have to turn over to 
accumulate a USABLE  quantity say 10 tonnes?  Too much I would guess. 
the man to ask would be Prof. John S lewis at U of A Tucson.
Regards
Bill Jaeger