On July 15, 1903, the four compartment Junction Shaft was started by the Junction Development Company. The shaft was sunk rapidly making about 85ft. of depth per month.  Diamond drill holes were used to guide the development of the shaft. One drill hole was even drilled from the bottom of the shaft in an effort to locate the limestones. At a depth of 850ft. enough water was entering the shaft that it was uneconomical to continue sinking. On July 31, 1904, 45 sinking buckets filled with water were being raise during day out of the shaft. Pumps were installed to handle the water, but being steam operated the temperatures underground were unbearable at the pump stations, exceeding 120° F. A fifth compartment was raised to handle the steam pipes for the pumps and reduce the temperature. A drift was also being driven on the 910 level to the Briggs Mine for ventilations. The inflow of water directed exploration for a time. The company wanted to ideally keep the water inflow at under 1,500 gallons per minute and no more than 2,000 gallons a minute. Thus sinking was stopped at the 1,006 ft. level and development work consisted of drifting on the 850, 910, 975 and 1006 ft. levels. During 1905, the Junction Development Company became the short-lived, Junction Mining Company. This new company became part of the Superior and Pittsburg Copper Company in 1906. A steel headframe and double drum hoist were installed. The 1000 level became the main pumping station. In July 1907, massive pumps were installed with fly wheels weighing 12 tons  on 1000 level. A total of nine rail cars were needed to hold pumps and parts. The stations to be cut underground were expected to be huge.  To hold one pump, an area big enough for “A six-horse team could turn on a trot without any trouble whatever.” was needed. This brought the 1000 level pump station to 5000 gpm capacity. Fortunately, as the ground was drained, the levels dried up and by 1909 only the bottom or 1500 level was producing a significant water. It became necessary in early 1908 to install three deck cages to handle the ore being mined. Both oxide and sulphide ores were being produced. A timbered shaft is a fire hazard and in 1912. It became apparent if a fire even shut down the pumping of water at the Junction for a single hour all the operating levels in the Junction, Hoatson and Briggs Mines would be lost. The Junction Shaft needed to be concrete lined for fire safety. Ore hoisted was diverted to the Hoatson and the tedious work concreting the shaft began. During the concreting project the shaft was flooded from the 1800 level to the 1500. When the upper portions of the shaft were finished the shaft was pumped out and the last 300 ft. was concrete lined. During the concrete work the shaft was being converted to use five-ton skips with a large pocket built on the 1400 level. The 1400 level was built has a haulage level with electric locomotives. The thought was the Junction would hoist the majority of ore produced by the Calumet & Arizona Mines. Natural ventilation no longer provided adequate air flow for the Calumet and Arizona mines. At the Junction four blowers were installed with a system of air doors, in 1915. The Campbell shaft was began in 1916 with the original intent that it would be used as a ventilating shaft for the Junction. After years of remaining 1,800 feet deep, in 1920 sinking of the Junction resumed and it was lowered to the 2200 level. The following year compartments 4 and 5 were sunk to the 2300 level. Then the remaining compartments were raised from the 2300 level up to the 1800 level. The well-known pump station on the 2200 level was built in 1924 and all the steam pumps were shut down. The following year one billion one hundred million gallons of water were pumped at Junction Shaft. A cast-steel water door in a concrete frame was built 600 ft. from the shaft on the 2200 level to protect the shaft from sudden flooding. In 1931, the Calumet & Arizona Mining Company merged with Phelps Dodge Copper Queen Branch. Almost immediately, the Copper Queen’s mines of were shut down and the Junction began to be modified to mine ore that traditionally been part of the Sacramento Mine. A shaft station was cut on the 960 level and the 1200 level was fitted to serve as a haulage level. These were to provide access to the Sacramento Mine’s block cave and Southeast Extension stopes. The 2200 level pumping capacity was double in preparation for continued sinking of the Junction Shaft in 1933. By the end of 1934, the Junction was sunk to the 2710 ft. level with stations cut on the 2566 and 2700 levels. On August 30, 1941, water was struck in 12 crosscut on the 2700 level . The massive amount of water flooded the mines to above the 2566 level of the Campbell. Deep well pumps were borrowed from the Phelps Dodge mines at Morenci, Arizona and before 1942, the 2700 level had been recovered and restored. In 1958, mining officially ended in the Junction mine, but the shaft and a limited amount of workings were maintained. During 1963, a vast amount of acidic water was released from the Czar-Holbrook mine area. The pumps on the 1800 struggled to hold it back. Miners diverted the water down  raises and sent it to the 2200 level. It was treated with lime to de-acidify the water, so it could be pumped from the 2200 level. The pumps on the 2200 level and the 2700 continued to be used until 1985. In 1982, severe flooding occurred with acidic mine waters from the abandoned workings. The water came from a storm in Mule Gulch. These waters drained into the  mine workings and overcame the pumps on the 1800 level and water poured directly down the shaft to the 2700 level. In 1985, After the cessation of the precious metal mining in the Campbell Mine and salvage work, the pumps on the 2700 level Junction and 3200 level Campbell Mine were simply turned off on. The 2200 level pump was operated on a one shift basis to provide leach water. Water rose rapidly at 4 ft. a day a massive amount considering the hundreds of miles of mine workings being flooded. Slowing down, it began to rise about 2 ft. a day when it reached the 2200 level  With water rising , on May 7th,1986 the power to the 2200 level shaft station was turned off in preparation of the flooding a few days later at 3:00 am May 11,  “Mother’s Day” water began flooding the station. During the 1990’s, the 770 adit from the Lavender Pit to the Junction shaft was completely retimbered. The 770 station was retimbered as well and the shaft to at least this level was useable. This section of the mine was used for mine safety training. The shaft was completed at a depth of 2,727ft with five compartments.