North Star Gold Mine
General Information
Name of Mine or Prospect: North Star Mine
Primary Deposit: Gold
Secondary Deposit: Copper, Silver
State: Arizona
County: Pinal
District: North Star District
Status: Abandoned
Deposit Type: Lode vein
Ore Reserve Calculation: 1986: 453,000 tons, grading 2.82 g/t Au per ton in tailing retreated -Bronsons
First Year of Production: 1909
Last Year of Production: 1911
Re-opened: 1983
Materials: Malachite, Chalcocite, Tenorite, Chrysocolla, andesite
Gangue: Quartz/Chlorite
History of the Mine;
The North Star Gold Mine is rather situated at the foot of the precipitous southern wall of the main Kofa Mountain mass, which is located about 1 3/4 miles north of the King of Arizona Gold Mine. It's rather separated from the King of Arizona Gold Mine by a gravel floor reentrant that commonly separates it from the spur that contains the King of Arizona Lode. The North Star Mine is also situated near the base of the lava capped Mesa, and at an elevation of nearly 2,000 feet. Between the overlying hills where the King of Arizona Mine and the North Star Mine are located is a much low lying ground that's within an outwash deposit.
It was in 1906, when the North Star vein was discovered, by Felix Mayhew, and a small amount of prospecting was carried out during that year. This mainly consisted of exposing the main vein mass further by trenching which would lead to sampling of the vein. Encouraging results had came from this vein that need more follow up development exploration to be conducted on it which Felix Mayhew did not have the capital in doing this type of work. By the end of 1906, Mr. Felix Mayhew had rather came to agreements to sell the project off to syndicate who would develop this project through an adit and two shafts.
It was in 1907, when the syndicate had officially paid Felix Mayhew a sum of $350,000 for the property in obtaining 100% interest in it. The Golden Star Mining Company was incorporated at this time as it would secure the required amount of capital to develop this mining project. During 1907, some problems were encountered as the company's newly acquired property was located high up in the Kofa Mountains and wasn't near any source of water. This resulted in securing a well drilling contractor in order to fine a source of water it could use for its mining operations. This resulted in drilling nearly 9 holes before water was intersected from a desert area that was 5 miles away from the North Star Gold Mine. Contracting was officially done in constructing a well that would be capable of running the cyanide plant and was achieved by the King of Arizona Construction Company.
Development at the time was also progressing when a small adit was driven for a short distance into the Kofa Mountain Range to explore this vein system further. Upon taking samples it was feasibly considered encouraging to further evaluate the potential of this gold prospect that was only discovered a year earlier in 1906. A shallow prospect shaft was additionally completed to a depth of 90 feet where 17 1/2 tonnes of ore was taken to be sampled that ended up producing $9,772.00 in gold at the time. Development had continued at this project throughout 1907, and into 1908, when some major development work would be done. From all production sampling that year, the North Star Mine would go onto producing 232 ounces of silver, and 464 ounces of gold that came from this mine prospect.
With the mine continuing to show encouraging results it was at this time when a 50 ton cyanide plant was erected during the operating season of 1908. Progress was rather ongoing as a new production shaft was being collar down to a depth of nearly 150 feet below the surface to explore the working further. The vein which was being followed had been extensively developed by drifting and crosscutting that was done on it to explore its underground continuity further. The very first level that was engineered to explore the North Star Vein was cut and station on the mines 100-foot horizon where lateral development was undertaken. No additional production was made from this mine as the on-site cyanide plant was completed towards the end of 1907. By this time the company had erected the main mine buildings that included a power house, blacksmith shop, compressor house, and a headframe that was 20 feet tall. Machinery which was used within the shaft operation was rather equipped with a Hoist and an Ingersoll Rand Compressor that was place in order to provide the necessary power in running the hoist with a bucket attach to it.
It was rather in 1909, when work was being commenced at a much bigger scale as the No. 2 shaft was depended to greater depths of 250-feet below the surface. This resulted in cutting a station on the 200-foot horizon of the North Star Mine, which was made into a station as development progress on the 100-foot level. A better means of access was shortly after provided by continuing the main adit in order to connect with the 100-foot level of the No. 2 production Shaft operation. Ladderways at this time were additionally extended from the main shaft to a depth of nearly 200 feet below the surface at the North Star Gold Mine. The 50-ton cyanide plant had additionally treated a minor amount of ore in order to produce 9,937 ounces of silver, and 24,491 ounces of gold, which had valued at $511,305. The North Star Gold Mine was rather located 1/2 km from the settlement town-site of Kofa, that was named after the King Of Arizona Gold Mine discovery.
The North Star Gold Mine was yet again achieving silver and gold production for the second year in a row as a large tonnage of ore was being produced at this mine. It was in 1910, when the main No. 2 Production Shaft was being sunk to the 350-foot level at the North Star Gold Mine that had continued to be laterally developed by drifting and crosscutting. This resulted in cutting another level that was station on the 300-foot horizon, and development work was now progressing on the 200-foot level. Only a minor amount of development had taken place on the 100-foot level as new stopes were being prepared for mining in 1911. In total production, it was reported that the cyanide plant would go onto producing 7,492 ounces of silver, and 15,945 ounces of gold that came from the underground workings.
By 1911, the shaft was continued to a depth of 500-feet, where to new levels were establish on the 400- and 500-foot horizons of the mine. Development along with sampling was undertaken on these levels that had proven that the ore within the North Star Mine working was decreasing in grade. Much of this had resulted in mining the 200-foot horizon as a minor amount of ore was left within the stope operation on this level. One last production was reached from this when the cyanide plant would go onto producing 2,731 ounces of silver and 6,099 ounces of gold was taken from this lode deposit in 1911. The mine itself was fairly large at this time that included several buildings that had been place in order to develop and operate the North Star Mine Site. Lateral development had amounted to 3,500 feet that included drifting and crosscutting on the North Star Vein, which was completed from 1907 to 1911. Ore that came from this mine was typically crushed at this time, in which it was amalgamated and had went through cyanitization in order to extract the gold from the ore.
A tailing reclamation plan was set in place when Bronsons had constructed its very own agitation leach facility and began a minor amount of production from this mine site. This resulted in calculating ore reserves within the mine that had amounted to 453,000 tons of ore grading, 2.82 g/t of Au in 1986. No major plans were done after that as the company had decided to withdraw from the production of tailings and the ore was left on site after a feasibility was conducted.
Geology and ore deposit information:
The Ore-body at the North Star Mine rather appears in a lode and a vein of solidified andesite breccia, and quartz, that strike east and dip 060 degrees north. This type of lode is also considered to be up to 10 feet in average width at the North Star Gold Mine project in the Kofa Mountains of Arizona, United States. It typically crops out for several feet on the country rock, and can be seen extending for quite a distance to the east and west from the main mine area at the North Star Gold Mine. The main lode at this mine is reported to contain low grade ore material, and is commonly considered to extended for several miles along the hills of the Kofa Mountain Range. At the mine, the hanging wall is rather a pink-flow banded biotite andesite, and at the foot wall a dark calcareous slate of probable Precambrian Age. This typical slate contains finely disseminated pyrite, and the main lode is known to occur along a fault. Some extremely high-grade bodies of gold ore were commonly known to also be within chimneys or shoots that pinch easterly. They also occur in variable width and the gold content demonstrates rapidly with increasing depth, which it's at the fifth level that the average tenor of the ore was below that required for its profitable treatment at $14 in gold per ton. Assays that were taken from drifts beyond the enrich parts of the lode had show gold and silver in variable amounts, with a probable average value of $2 per ton. Some of the surface ore at the mine was considered to have been extremely high-grade, in which one streak from the footwall had average between $6 to $20 in gold a pound, and the ore that had valued thousands of dollars was additionally stolen from the property. Some of the stope out parts were considered to have also average 10 feet. The No. 2 Shaft was also sunk in the approximate center of a shoot that contained rather high-grade ore over 500 feet long, while the tender of which exceeded $50 a ton. It's also on the second level where the high-grade ore had occurred in much smaller shoots that's separated by ledge matter of relatively low grade ore. On the third, fourth and fifth level, it was determined that the shoots had appear to have joined in order to form a shoot which is comparable in length of that on the first level, but show rapidly decreasing metal content by a possible fault.
It's on the surface that the vein angular fragments of the pink-andesite, which is altered in places to green and grey tints, which are cemented to an extremely hard rock by banded chalcedony quartz. These band are fairly well shown as they are deposition of minute crystals of sulphides, in which contain mostly pyrite. Pyrite is also typically considered to occur through the altered andesite at this gold mine project, in which some vugs of this material are lined with sparkling quartz crystals. The andesite also has a green type of micaceous mineral that occurs in altered andesite, as well as a little chloride and episode. Ore that occurs at the North Star Mine is mainly valued chiefly for its gold content as its primarily high-grade, but little silver also occurs in about the ratio of it's own occurrence. In total production, it was reported that this mine had amounted to a value of $1,100,000, in which a portion of it was considered to have been stolen. From the time of the mines closure, various mining operations were conducted for mainly place gold deposits in and around the North Star Gold Mine Site, which were relatively small scale. The North Star Mine also rather contains a large tonnage of material and much lower grade material is reported to occur with depths of this deposit. It was reported that these mines had also contained a large amount of material that was classified as non-economical to develop during 1911, and can be reasonably developed and mined at a profit now. Gold which occurs at this mine is commonly known to occur freely and is very finely divided, that's associated in fine sulphides that occur in chalcedony quartz. Copper is also commonly present at grades which are sufficient to have a strong effect on the economics of an excavation project. Silver can also be economically recovered from this site but would have little effect on viability of the mining project.
Name of Mine or Prospect: North Star Mine
Primary Deposit: Gold
Secondary Deposit: Copper, Silver
State: Arizona
County: Pinal
District: North Star District
Status: Abandoned
Deposit Type: Lode vein
Ore Reserve Calculation: 1986: 453,000 tons, grading 2.82 g/t Au per ton in tailing retreated -Bronsons
First Year of Production: 1909
Last Year of Production: 1911
Re-opened: 1983
Materials: Malachite, Chalcocite, Tenorite, Chrysocolla, andesite
Gangue: Quartz/Chlorite
History of the Mine;
The North Star Gold Mine is rather situated at the foot of the precipitous southern wall of the main Kofa Mountain mass, which is located about 1 3/4 miles north of the King of Arizona Gold Mine. It's rather separated from the King of Arizona Gold Mine by a gravel floor reentrant that commonly separates it from the spur that contains the King of Arizona Lode. The North Star Mine is also situated near the base of the lava capped Mesa, and at an elevation of nearly 2,000 feet. Between the overlying hills where the King of Arizona Mine and the North Star Mine are located is a much low lying ground that's within an outwash deposit.
It was in 1906, when the North Star vein was discovered, by Felix Mayhew, and a small amount of prospecting was carried out during that year. This mainly consisted of exposing the main vein mass further by trenching which would lead to sampling of the vein. Encouraging results had came from this vein that need more follow up development exploration to be conducted on it which Felix Mayhew did not have the capital in doing this type of work. By the end of 1906, Mr. Felix Mayhew had rather came to agreements to sell the project off to syndicate who would develop this project through an adit and two shafts.
It was in 1907, when the syndicate had officially paid Felix Mayhew a sum of $350,000 for the property in obtaining 100% interest in it. The Golden Star Mining Company was incorporated at this time as it would secure the required amount of capital to develop this mining project. During 1907, some problems were encountered as the company's newly acquired property was located high up in the Kofa Mountains and wasn't near any source of water. This resulted in securing a well drilling contractor in order to fine a source of water it could use for its mining operations. This resulted in drilling nearly 9 holes before water was intersected from a desert area that was 5 miles away from the North Star Gold Mine. Contracting was officially done in constructing a well that would be capable of running the cyanide plant and was achieved by the King of Arizona Construction Company.
Development at the time was also progressing when a small adit was driven for a short distance into the Kofa Mountain Range to explore this vein system further. Upon taking samples it was feasibly considered encouraging to further evaluate the potential of this gold prospect that was only discovered a year earlier in 1906. A shallow prospect shaft was additionally completed to a depth of 90 feet where 17 1/2 tonnes of ore was taken to be sampled that ended up producing $9,772.00 in gold at the time. Development had continued at this project throughout 1907, and into 1908, when some major development work would be done. From all production sampling that year, the North Star Mine would go onto producing 232 ounces of silver, and 464 ounces of gold that came from this mine prospect.
With the mine continuing to show encouraging results it was at this time when a 50 ton cyanide plant was erected during the operating season of 1908. Progress was rather ongoing as a new production shaft was being collar down to a depth of nearly 150 feet below the surface to explore the working further. The vein which was being followed had been extensively developed by drifting and crosscutting that was done on it to explore its underground continuity further. The very first level that was engineered to explore the North Star Vein was cut and station on the mines 100-foot horizon where lateral development was undertaken. No additional production was made from this mine as the on-site cyanide plant was completed towards the end of 1907. By this time the company had erected the main mine buildings that included a power house, blacksmith shop, compressor house, and a headframe that was 20 feet tall. Machinery which was used within the shaft operation was rather equipped with a Hoist and an Ingersoll Rand Compressor that was place in order to provide the necessary power in running the hoist with a bucket attach to it.
It was rather in 1909, when work was being commenced at a much bigger scale as the No. 2 shaft was depended to greater depths of 250-feet below the surface. This resulted in cutting a station on the 200-foot horizon of the North Star Mine, which was made into a station as development progress on the 100-foot level. A better means of access was shortly after provided by continuing the main adit in order to connect with the 100-foot level of the No. 2 production Shaft operation. Ladderways at this time were additionally extended from the main shaft to a depth of nearly 200 feet below the surface at the North Star Gold Mine. The 50-ton cyanide plant had additionally treated a minor amount of ore in order to produce 9,937 ounces of silver, and 24,491 ounces of gold, which had valued at $511,305. The North Star Gold Mine was rather located 1/2 km from the settlement town-site of Kofa, that was named after the King Of Arizona Gold Mine discovery.
The North Star Gold Mine was yet again achieving silver and gold production for the second year in a row as a large tonnage of ore was being produced at this mine. It was in 1910, when the main No. 2 Production Shaft was being sunk to the 350-foot level at the North Star Gold Mine that had continued to be laterally developed by drifting and crosscutting. This resulted in cutting another level that was station on the 300-foot horizon, and development work was now progressing on the 200-foot level. Only a minor amount of development had taken place on the 100-foot level as new stopes were being prepared for mining in 1911. In total production, it was reported that the cyanide plant would go onto producing 7,492 ounces of silver, and 15,945 ounces of gold that came from the underground workings.
By 1911, the shaft was continued to a depth of 500-feet, where to new levels were establish on the 400- and 500-foot horizons of the mine. Development along with sampling was undertaken on these levels that had proven that the ore within the North Star Mine working was decreasing in grade. Much of this had resulted in mining the 200-foot horizon as a minor amount of ore was left within the stope operation on this level. One last production was reached from this when the cyanide plant would go onto producing 2,731 ounces of silver and 6,099 ounces of gold was taken from this lode deposit in 1911. The mine itself was fairly large at this time that included several buildings that had been place in order to develop and operate the North Star Mine Site. Lateral development had amounted to 3,500 feet that included drifting and crosscutting on the North Star Vein, which was completed from 1907 to 1911. Ore that came from this mine was typically crushed at this time, in which it was amalgamated and had went through cyanitization in order to extract the gold from the ore.
A tailing reclamation plan was set in place when Bronsons had constructed its very own agitation leach facility and began a minor amount of production from this mine site. This resulted in calculating ore reserves within the mine that had amounted to 453,000 tons of ore grading, 2.82 g/t of Au in 1986. No major plans were done after that as the company had decided to withdraw from the production of tailings and the ore was left on site after a feasibility was conducted.
Geology and ore deposit information:
The Ore-body at the North Star Mine rather appears in a lode and a vein of solidified andesite breccia, and quartz, that strike east and dip 060 degrees north. This type of lode is also considered to be up to 10 feet in average width at the North Star Gold Mine project in the Kofa Mountains of Arizona, United States. It typically crops out for several feet on the country rock, and can be seen extending for quite a distance to the east and west from the main mine area at the North Star Gold Mine. The main lode at this mine is reported to contain low grade ore material, and is commonly considered to extended for several miles along the hills of the Kofa Mountain Range. At the mine, the hanging wall is rather a pink-flow banded biotite andesite, and at the foot wall a dark calcareous slate of probable Precambrian Age. This typical slate contains finely disseminated pyrite, and the main lode is known to occur along a fault. Some extremely high-grade bodies of gold ore were commonly known to also be within chimneys or shoots that pinch easterly. They also occur in variable width and the gold content demonstrates rapidly with increasing depth, which it's at the fifth level that the average tenor of the ore was below that required for its profitable treatment at $14 in gold per ton. Assays that were taken from drifts beyond the enrich parts of the lode had show gold and silver in variable amounts, with a probable average value of $2 per ton. Some of the surface ore at the mine was considered to have been extremely high-grade, in which one streak from the footwall had average between $6 to $20 in gold a pound, and the ore that had valued thousands of dollars was additionally stolen from the property. Some of the stope out parts were considered to have also average 10 feet. The No. 2 Shaft was also sunk in the approximate center of a shoot that contained rather high-grade ore over 500 feet long, while the tender of which exceeded $50 a ton. It's also on the second level where the high-grade ore had occurred in much smaller shoots that's separated by ledge matter of relatively low grade ore. On the third, fourth and fifth level, it was determined that the shoots had appear to have joined in order to form a shoot which is comparable in length of that on the first level, but show rapidly decreasing metal content by a possible fault.
It's on the surface that the vein angular fragments of the pink-andesite, which is altered in places to green and grey tints, which are cemented to an extremely hard rock by banded chalcedony quartz. These band are fairly well shown as they are deposition of minute crystals of sulphides, in which contain mostly pyrite. Pyrite is also typically considered to occur through the altered andesite at this gold mine project, in which some vugs of this material are lined with sparkling quartz crystals. The andesite also has a green type of micaceous mineral that occurs in altered andesite, as well as a little chloride and episode. Ore that occurs at the North Star Mine is mainly valued chiefly for its gold content as its primarily high-grade, but little silver also occurs in about the ratio of it's own occurrence. In total production, it was reported that this mine had amounted to a value of $1,100,000, in which a portion of it was considered to have been stolen. From the time of the mines closure, various mining operations were conducted for mainly place gold deposits in and around the North Star Gold Mine Site, which were relatively small scale. The North Star Mine also rather contains a large tonnage of material and much lower grade material is reported to occur with depths of this deposit. It was reported that these mines had also contained a large amount of material that was classified as non-economical to develop during 1911, and can be reasonably developed and mined at a profit now. Gold which occurs at this mine is commonly known to occur freely and is very finely divided, that's associated in fine sulphides that occur in chalcedony quartz. Copper is also commonly present at grades which are sufficient to have a strong effect on the economics of an excavation project. Silver can also be economically recovered from this site but would have little effect on viability of the mining project.