The Treasure Box Mining Company was one of the largest mining operations in City Creek Canyon, it's large dump giving evidence to its reported 10,000 feet of underground workings. Still, relatively few people know it even exists.

Located in the early days of Utah prospecting, it was worked slowly and sporadically on two levels.  Initial work was conducted on the upper level some 250 feet above the lower portal. (Shown above)  Assay reports and tonage are not known for this earlier period, but most likely silver and lead were the primary metals being sought. Some data for the later period is known.

World War I brought an increased demand for zinc. With that demand, work on the property resumed with vigor. By early 1918 more than 9000 tons of high grade ore was exposed in the upper level, and a contract was let to extend the lower tunnel some 300 feet in hopes of striking that same rich vein at depth. Assays of this ore showed 29 to 49% zinc, and 6 to 19 oz. of silver to the ton. In addition, selected ore samples showed more than 80% pure lead. There is no report of the company ever striking that same rich vein, but it is likely that some ore was encountered.

Whatever the reports, the high grade ore was gone by January of 1919, and the first in a long line of stock assessments was levied, 5 mils per share, due and payable by March. For the next decade, with only one exception, every mention of the Treasure Box property in the Salt Lake papers was another notice of assessment.  That exception, in 1921, detailed the election of company officers.  Last mention of the property in The Mining Review, happened November 15th, 1928, with notice of a 5 cent assessment due and payable by December 3rd.