While it possible could add some oxygen, I don't think it would work to well, as it is commonly used for cyanide destruction.  see: https://www.911metallurgist.com/blog/cyanide-destruction-methods

It would be much better to use a "lance" to feed additional air or oxygen, however you will need to ensure that you do so without upsetting the agitator.  Several forms of air-distributor are available.

Peroxide (or oxygen) will work, you want to add a small, diluted, amount periodically in order to maintain an elevated DO level. (Use a DO probe and add peroxide when the DO levels drop below 8 ppm). 

As SmartDog mentioned this can be a bit dangerous because if you add too much you drop the pH, destroy cyanide and can have HCN gassing.

Alternatively you could use a chemical oxidant like SeproLeach or LeachAid which will likely be slightly more expensive but you just need to add one batch of dry pellets at the start of the leach and then there is no need to monitor DO levels, periodically dose peroxide or construct an air/oxygen sparging system.

Calcium Peroxide would be better for oxygen addition than hydrogen peroxide, and as Smart Dog says hydrogen peroxide is used as an oxidiser to neutralise cyanide to cyanate.  Hydrogen peroxide is often added to CIL/CIP feed streams as an oxidiser.  Run some tests using calcium peroxide and see how much cyanide is neutralised to see if it will greatly impact on on cyanide in your vat leaching system.  Also run bottle roll tests to ascertain what recovery improvement benefit you may be able to get using calcium peroxide.

Hi Kahonde

All the above are right but I'm assuming that you only have hydrogen peroxide to work with. We recently did exactly the same thing (for probably the same reasons). We added hydrogen peroxide to increase the DO, the trick is to have the gold grades that will allow a doubling of your cyanide consumption and to add the peroxide in small enough doses to minimise the cyanide loss through oxidation.

We used a small dosing pump to inject the peroxide into the tails line (pipe returning barren solution to the vat), estimated dosing was about 30ppm H202. This effect lasts only a short time, 4-6hrs, so continuous peroxide addition is needed. I don't know how to measure the exact peroxide concentration so we did it by looking at the DO concentration and tried to keep that as low as possible (7-8 mg/l).

Unless you are doing an intensive (high) cyanide concentration leach you could have your DO down in the mid 5s without effecting your kinetics too much in a vat.

Other factors to be aware of...

DO levels are naturally higher in the morning than in the afternoon (due to ambient temperature)

We increased DO by using sprinklers in the vat (also increased evaporation losses but was a cheap alternative).

Attached is a of pic of our setup and a graph of DO Vs CN (active)

Have from your experience how long does it take to recover or dissolve all gold in the VAT/Heap leach? Let's say the dissolve oxygen is sufficient and the concentration of cyanide solution is about 0.2 - 0.3% or 2g/L?