You are hereSampling Ratios
Sampling Ratios
For instance, if a placer sample weighing fifty pounds was concentrated and sent to the assayer and the weight of the gold silver bead was 25 milligrams and the weight of the gold bead after being divided was 22.5 milligrams ,then the material in the taster would assay at 0.03 ounces of gold per ton (22.5 milligrams 50 ib times 40 –900 milligrams 2000ib—0.900 grams ton .0.900 grams ton divided by 31.1 grams ounce—0.03 ounces ton) separation shows, that 10 percent of the placer gold in the sample is poised of silver , consequently the distinction of this placer is 900. If the assay was shape from the weight of the gold silver bead the results would be 10 percent higher. Following the sample, results are studied a placer deposit will fall into one of the next category’s: certainly not profitable, certainly profitable or a medium case. The previous case is familiar and the information obtains during sampling and testing can help to decide whether the medium deposit can or cannot be mined for a profit.
A primary step is to resample certain areas to validate the test results. Constantly resample extremely hot or high grade areas, for these may be holding your sample normal too high. If the consequences from different areas are quite regular, few larger samples may be required to give a more precise respond. When samples results vary really from one area to another a larger amount of samples may be required to give a more exact average for the whole deposit. The results of the concentrating test should also be calculated.
Was all of the gold in the samples found in the concentrate or was some of it found in the mids or tails? This lighter gold if it is near may be complicated to save in an actual placer process. Laboratory gear is calculated and can be controlled to make a very high recovery. Assembly equipment will not essentially make such a high recovery and gold which was complicated to save in the lab very well may be lost in the field.
The finest way to get the last answer is to move provisional equipment onto the site and run some hundred tons of material .This is expensive but it should give a exact answer .The equipment that would be required contain a screening machine, a sluice box and a front end loader or suction tool to pickup the material .If large rocks are present a grizzle will be required ahead of the screen. The material is screened and then put across the sluice box and the concentrate saved. This kind of sampling not only provides you large samples but also gives you a chance to try improving your recovery. Examination can be done by changing the pitch of the sluice, shifting the screen size demanding diverse riffling in the sluice and rerunning the rails under special conditions to see if any gold in them can be saved .These variations and others should give a better suggestion of what you may suppose to recover if the deposit is worked.
