STATISTICS
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STATISTICS
The average yield of the gold mines in Piedmont, in the North of Italy, since 1863, is as follows:--
Ozs. Dwts.
Val Toppa Gold Mining Company - - 1 5 per ton.
Vallanzasca Gold Mining Company - - 0 15 per ton.
Pestarena Gold Mining Company - - 2 10 per ton.
QUARTZ MINES IN CALIFORNIA IN 1861.
| COUNTY.
|
No.
of
Mills
|
Tons
Crushed
24
hours
|
Loss
of
Mercury
ton
|
Cost of
Extracting
Quartz
from Mine
|
Cost of
Treatment
ton
|
Average
Yield
ton
|
|
|
|
|
|
dols.
|
dols.
|
ozs. dwts. grs.
|
| Mariposa
|
4
|
149
|
0.014
|
5.24
|
dols.
2.57
|
0 19 15
|
| Tuolumne
|
8
|
112
|
0.026
|
5.53
|
2.12
|
1 3 22
|
| Calaveras
|
3
|
40
|
0.126
|
1.75
|
5.7
|
2 2 12
|
| Amador
|
7
|
196
|
0.071
|
2.82
|
1.95
|
0 11 14
|
| El Dorado
|
3
|
45
|
0.054
|
3.87
|
1.77
|
0 16 14
|
| Plumas
|
2
|
25
|
0.022
|
3.73
|
6.27
|
1 0 5
|
| Sierra
|
2
|
40
|
0.030
|
5.3
|
2. 12
|
0 14 21
|
| Nevada
|
9
|
157
|
0.067
|
13.00
|
2. 43
|
1 17 2
|
According to Mr. Asburner, the average cost of the treatment of ores in California in 1866, is as follows:--
|
|
Dollars.
|
| In Water Mills, water free
|
1.22
|
| " " water purchased
|
1.60
|
| In Steam Mills, burning wood
|
2.14
|
It must be remembered that in California the ton is taken to weigh only 2,000 lb.
The principal mine in Brazil, the Morro Velho, averages 10 dwts. to the ton. This Company has
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191 stamp-heads at work, and employs 2,400 hands. During the year ending 23rd March, 1867, the net profits were £109,407 15s. 8d. The average cost, including all expenses, is 25s. a ton, and the usual loss of gold is 5dwts. to the ton in the tailings.
QUARTZ MINES IN NOVA SCOTIA.
QUARTZ MINES IN VICTORIA IN 1866.
In Victoria, in 1867, there were 66,243 gold miners, of which 34,107 Europeans, and 18,067 Chinese, were employed on alluvial diggings, and 14,044 Europeans, and 25 Chinese, in quartz mining. On the alluvial mines there were 471 engines, of 9,330 horse power. The approximate value of the mining plant was £2,047,570. The number of square miles mined upon was 818, and the number of quartz reefs reported to be auriferous, 2,421.
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The gold yield of California reached its highest point in 1853, when it amounted to £13,000,000; since then it has gradually fallen, year by year, until, in 1867, it was only £5,000,000. About one third of the gold now obtained from there is the produce of quartz-mining.
The aggregate horse power of the machines was 9,231, and the number of stamp-heads 5,437.
The prices paid for treating the quartz ranged from 4s. to 30s. per ton.
RETURN OF GOLD OBTAINED IN VICTORIA FROM QUARTZ VEINS.
ozs. dwts.
1863.....................493,499 O
1864.....................603,618 5
1865.....................450,000 0
The following table of the average value of gold from different places in New Zealand has been kindly furnished by the Bank of New Zealand:--
| Locality.
|
Assay--Carats.
|
Value per oz.
|
| OTAGO
|
|
£ s. d.
|
| Dunedin
|
22.4
|
3 19 3
|
| Queenstown
|
22.22
|
3 18 7
|
| Arrow
|
22.33
|
3 19 1
|
| Dunstan
|
22.4
|
3 19 3
|
| Manuherikia
|
22.6
|
3 19 11
|
| Lawrence
|
23.05
|
4 1 7
|
| Waitahuna
|
23.1
|
4 1 8
|
| Mount Ida
|
23.2
|
4 2 0
|
| Dunstan Creek
|
23.l
|
4 1 8
|
| Waikouaiti
|
22. 1
|
3 18 2
|
| Tokomariro
|
22.6
|
3 19 11
|
| Macrae's Flat
|
23.04
|
4 1 7
|
| WESTLAND
|
|
|
| Hokitika
|
23.088
|
4 1 8
|
| Greymouth
|
23.0
|
4 1 4
|
| MARLBOROUGH
|
|
|
| Picton
|
22.776
|
4 0 7
|
| NELSON
|
22.344
|
3 19 0
|
| INVERCARGILL
|
23.184
|
4 2 0
|
| AUCKLAND
|
18.648
|
3 6 0
|
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The average of Auckland is taken from eight assays, the highest giving .951, and the lowest .593.
The following are other assays from localities at the Thames:--
| Locality.
|
Assay--Carats.
|
Value per oz.
|
|
|
|
£ s. d.
|
| Kennedy's Bay
|
21.8
|
3 16 0
|
| Tookey's Claim
|
15.225
|
2 15 0
|
| Barry's
|
14.113
|
2 10 0
|
| Hunt's
|
14.000
|
2 9 8 1/4
|
| Golden Crown
|
15.79
|
2 15 10
|
AVERAGE VALUE OF GOLD FROM VARIOUS PARTS OF THE WORLD.
QUANTITY OF GOLD EXPORTED FROM AUCKLAND FROM 1st AUGUST, 1867, TO 1st AUGUST, 1868.
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APPROXIMATE STATEMENT OF THE REVENUE AND EXPENDITURE OF THE THAMES GOLD FIELDS, FROM AUGUST, 1867, TO 13th JUNE, 1868.
GENERAL RECEIPTS, 1 GENERAL EXPENDITURE
It will be noticed that while the receipts are only up to May 31st, the expenditure is estimated up to June 13th, so that the balance deficiency on May 31st was only £776 10s.; and as up to that time the gold duties had amounted to £2,114 19s. 10d., it is evident that on the 31st of May the receipts exceeded the expenditure by 1,339 9s. 10d.
QUANTITY OF GOLD IN QUARTZ.
It is sometimes useful to be able to ascertain roughly the amount of gold in a piece of quartz without destroying the specimen. This can be done in the following manner for Thames gold, the specific gravity of which is about 15.8:--
Weigh the specimen in air and multiply its weight by 1.9, next weigh it in water and multiply this weight by 3.12, subtract one from the other, and
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the result will be the weight of gold contained in the specimen. The specimen must, of course, be weighed in troy weight.
If A is the weight of the specimen in air, and W its weight in water then
The weight of gold = 3.12W - 1.9A
TABLE SHEWING THE RELATION BETWEEN THE QUANTITY OF GOLD PER POUND AND PER TON OF ORE.
To use this table, first find the quantity of gold contained in a pound of stone, by dividing the quantity of gold obtained by the number of pounds crushed. Then write beneath each other the number of ozs. dwts, and grs. corresponding to the different number of grains, or parts of a grain, of gold contained in a pound of stone, and add them up for the yield of a ton of ore. Thus: suppose that 501bs. of stone was crushed and yielded 583 grains of gold
