Tuesday, March 31, 2020

Phoenix Gold Mine Operations

The Phoenix Mine is located in the Cave Creek Mining District in Arizona about 35 miles north of Phoenix. It was one of the largest stamp mills in Arizona at 100 stamps and powered by a 200 Hp Corliss Steam Engine. Today there is nothing left of the original millsite. The area is known as Spur Cross and where the mill was originally it is now a paved parking lot. There is a shaft in the area, but I heard it has been closed off. It is worth while to show you the pictures of the mill taken in 1893. The pictures below are property of Cave Creek Museum, Cave Creek, AZ

I have put together a report on the cost of operations of the mill in 1914 taken from “Arizona Geological Survey Mining Data” for the Phoenix Mine. Before I give the report I would like to extend some information on the value of gold and currency between 1914 and 2020 below:

Gold was $20.67 an ounce, 2020 it is around $1600, depending on the economic state.
Money $100 back in 1914 would be worth $2,586.78 in 2020.

Formerly Cave Creek Gold Mine and Bully Cave Gold Mine
March 1914
NOTE: This document was taken from “Arizona Geological Survey Mining Data” for the Phoenix Mine.

History The Cave Creek Mine had produced more than $300,000 worth of gold during its 30 years existence since the property was discovered. The first production was from rich gold quartz outcrops on the south end of the Phoenix Claim. Subsequently a small mill was operated, and later a large stock company undertook the exploration of the property. An extensive mine development plan was partially carried out and the erection of a 100-stamp mill begun. The company found itself in financial difficulties before regular operations had been inaugurated. Later attempts to operate with insufficient equipment and limited capital or by leasing led to its loss and failure. The result was the financial involvement of the company and the passing of the control of the property finally to the present owners.
Properties The Cave Creek Property includes two full patented claims, the Phoenix and the West side, four claims held by location, and two patented mill site claims together with water-right locations. It is located 35 miles north of Phoenix, Maricopa County, Arizona in the Cave Creek Mining District.
Production costs The cost per ton as shown below is calculating a freight rate from Phoenix to the Cave Creek Mine of $7.00 per ton and labor working eight hour shifts.
                                                                                                                                                                                                                                                            $ Per Ton
Course Crushing By gyratory or Jaw Crushing before ore reaches stamps    $0.020
Stamp Crushing
Power: $8.00 per H.P. per month. 30 H.P. for each (10) stamps
100 stamps for crushing 500 tons daily                                                                0.160 
Pumping solutions, slime filters, 50 H.P. engine                                                   0.026
Agitation of slime, treat or similar system                                                             0.015
Supplies: Estimating a set of shoes and dies for 100 stamps to last 105 days
 at the cost of $125,000 per set.                                                                           0.020
Stems, liners, bossheads, screens, tappets, wedges, etc.                                   0.015
Sand Treatment
Filling and discharging and turning sand tanks for aeration                                 0.100
Repairing false bottoms, cocoa matting, etc.                                                       0.010
Slime Treatment
Filtering slimes on a basis of 50% slime to 50% sand                                         0.040
Discharging slime tails from filters                                                                       0.010
Cyanide at .8 ib. per ton of dry ore                                                                      0.220
Lime for settlement, etc.                                                                                      0.040
Zinc room attendance, cut zinc, fluxes, melting                                                  0.030
Labor  A table was constructed to break down the wages by hour, monthly and annual to clarify the pay scales for each worker. The original table listed a dollar value per shift for each of the workers that does not correlate to the number I calculated. The dollar number was about $2 a shaft more than I calculated. I cannot explain this difference. The numbers provided on the original document are under the hourly wages in parenthesis for your information.
Mill  Supt.

$.75   ($,50)
Millmen Helper
$.54   ($,38)
Filter Men
$.75    ($,50)
Solution Men
$.75   ($,50)
Slime Treatment Men
$.75    ($,50)
Engine Men
$.75   ($,50)
$.47   ($,31)
                                   Roll up                                                      $3,064           0.022

General Expenses per month
General Manager                                                                                    $150 
Assayer                                                                                                   $125
Supplies for assay office                                                                           $50
Bookkeeper                                                                                             $125
Master Mechanic                                                                                     $200
Mechanics (2)                                                                                          $300
Lubricants                                                                                                $150
Belting                                                                                                      $150
Other Supplies                                                                                         $200                         
                                                Roll up                                                 $1,450    0.096         

Marketing Bullion Insurance on same, figured at 2% of gross product              0.055
Metallurgical loss of 10% on ore with $2.75 per ton                                            0.275

Total Cost per Ton for milling and cyanide                                                           1.332 
Estimated cost per ton for milling                                                                         0.400

Total Cost per Ton for Mining & Milling                                                          $1.732