Tombstone Exploration Corporation announced in combination with Goldrock Resources Inc. and the Bonanza Mining Company that the construction phase is moving smoothly and on track for the complete build out of the heap leach pad and pond at the Bonanza Harquahala Gold Mine in La Paz County, Arizona. R.C. Moores, II, the Bonanza Mining Company President states, “5D Mining & Construction Inc. mobilized on site June 8 to prepare and construct Phase 1 production facilities. To date, the principal production area has been cleared, grubbed and rough graded to plan. Focus has been on digging out the pregnant solution pond, constructing pond berms and compacting to engineering specifications in preparation for installation of the leach pad liner and processing facility installation. Heap leaching is an industrial mining process used to extract precious metals and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials. Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the ore, whereas in situ mining lacks these liners and pulls pregnant solution up to obtain the minerals. Heap leaching is widely used in modern large-scale mining operations as it produces the desired concentrates at a lower cost compared to conventional processing methods such as flotation, agitation, and vat leaching.