220 FANNING AND EDDINGFIELD. 
which had been concentrated by hand-panning. The sample 
assayed 16.40 pesos per ton, and gives not only an indication 
of the value of the black sands distributed generally through the 
ground, but also an idea of the loss of gold by the dredge. 
The lot assayed 16 pesos per ton, and checks were readily 
obtained. This was due to its low value and to the small amount 
of free gold present. 
Influence of free gold upon the sampling.—Free gold was 
repeatedly picked out of the coarse meshes of the screen tests 
on lot 1, and the amalgamation tests showed a considerable 
percentage of free gold. The amount of free gold in the various 
splits is variable, and causes variations in the assays of those 
splits. The variations of visible gold in 3 splits of lot 1 are 
shown in the following table: 
TABLE III.—Visible gold in splits. Lot No. 1. 
Weight of 
Split gold in 100 
No. 
Screen. raise 
sample. 
Milligrams. 
1 On 10 eo ee a eek Se Sa we ae Se ie See oes 29.6 
Piel eae oaks he ek Cee SEU as TEE eee ee 18.5 
Sie do ehis. 5A Bent ZS ee Sees eee 12.9 
1 On 20 Ns aa ee eee eee oe ee en 14.2 
a eset GO Se 2 SAS 2 A ee A ee Rn ae ee | 23.9 
It is seen that in 3 splits of the original, the gold picked from 
the 10-mesh varies from 12.9 to 29.6 milligrams, and for the 
20-mesh varies from 11.7 to 14.2 milligrams. Computing from 
these data, the variations in the visible gold cause a difference 
of 29.90 pesos per ton in the value of the sample. 
In bucking down the samples for assay, pellets frequently were 
obtained on the screen (150-mesh), and the varying amounts 
indicated irregular distribution of free gold in the various splits. 
To illustrate, after pulverizing a sample so that it would pass 
60-mesh, rolling thoroughly, and then cutting twice for assay 
samples, it was found that one of the splits retained screen 
pellets equivalent to 1 peso per ton and the other retained pellets 
equivalent to 13.22 pesos per ton of the original material. The 
complete assay was 299.48 pesos per ton for the former and 
816.74 pesos for the latter, a difference due to irregular distribu- 
tion of the free gold as indicated by the pellets on the screen. 
