Gold Resource Corporation announced the results of a SK1300 compliant Technical Report Summary for an Initial Assessment (IA or the Technical Report) which comprises an updated Mineral Resource Estimate (MRE) and a financial analysis for the Company's 100% owned Back Forty Project (Back Forty or the Project), located in the Upper Peninsula of Michigan. This study is the result of veery strong technical work and represents a compete revision to the mine plan, process flow, project footprint and the elimination of any wetlands impact. The results suggest a very robust Project with a moderate capital investment and a 9-year mine life during which 504 koz of gold, 6,150 koz of silver, 61.6 Mlbs of copper and 778 Mlbs of zinc would be produced.

The Project consists in two open pit mines, an underground mine, a nominal 2,500 metric tonnes per day (?tpd?) processing plant and the supporting infrastructures. A 21-month construction period would be followed by open pit mining in the Pinwheel Pit and then in the Main Pit for the first 3 years. Development for the underground mine would start in Year 2 from inside the Main Pit to support the processing plant starting in Year 4. Study Details: The Back Forty Project is an advanced stage polymetallic exploration project fully owned by GRC located in the Upper Peninsula of Michigan.

The IA was prepared and compiled by GRC with support by independent consulting firms InnovExplo and Foth. Mineral Resources Estimates: The IA includes an updated MRE done by InnovExplo. No additional drilling has occurred on site since 2019, but the geological interpretation, interpolation parameters and NSR calculations were updated.

This represents an increase of 17% in the total value in the block model (NSR x tonnes) compared to the previous MRE. However, deductions for the gold and silver streams, along with the royalties, were included in the NSR calculations against the cut-off grade (?CoG?). These deductions were not part of the previous MRE.

When the deductions are included, the total value in the block model is 4% less than the previous MRE. The underground part of the MRE was confined using a Stope Optimizer software, which is more restrictive than the method used in the previous MRE. The CoG for open pit and underground were updated to reflect costs closer to the proposed mining methods.

In total, the Measured and Indicated resource reduced by 21% while the Inferred resource is within 1% of the previous MRE. The effective date of the MRE is September 30th, 2023. Mining: The mine plan consists of a combined open pit and underground mining operation at an average 2,600 tpd.

Open pit mining will take place from Year 1 to Year 4. Underground development will be initiated in Year 2 and underground production mining will continue to Year 10. Open pit mining will occur in two distinct areas, the Pinwheel pit and the Main pit. The Pinwheel pit will be mined first and contains material with a higher grade in gold and copper than the average resource.

This pit will be mined for 18 months. The Main pit will be started at the end of year 1 to complement the production of the Pinwheel pit. Waste material from the Main pit will be used to backfill the Pinwheel pit once its resources are exhausted.

The development of the underground mine will start at the end of Year 2 with a portal located inside the Main pit. Production from the underground mine will start replacing the open pit one in Year 4. Mining underground is accomplished mostly from long hole open stoping with stopes averaging 24,000 t. Processing: The processing facility will be used to process at a nominal rate of 2,500 tpd of mineralized material and up to 2,800 based on feed material characteristics over the LOM. The flowsheet consists of a three-stage crushing followed by ball mill to a target P80 size of 50 microns.

The facility will have two flotation circuits to recover copper and zinc. The copper and zinc circuits will see their respective concentrate filtered to reduce residual moisture content to approximately 10%. Both concentrates will be loaded for shipment to smelters. Zinc flotation tailings will be leached and dewatered using a press filter.

Solids will be washed and dewatered to 15% humidity in the press filter before being sent to dry stack. Filtrate from the press filter will be processed through reverse osmosis membrane for salt rejection and through the SART circuit. Cyanide species from the solution will be converted to NaCN.

Precious metals are recovered from solution in zinc precipitation circuit. Precious metal barren solution will be recirculated to leaching and recycled cyanide will be re-introduced. Cyanide destruction will be performed on excess dilute solution from the press filter not processed by SART and released to the collecting pond.

Paste backfill will be installed later during the life of mine when the underground mine will be in operation. The proposed process will recover zinc and copper concentrates, as well as gold and silver in the form of doré bars. SART process will also generate copper and zinc concentrate.

The copper concentrate flotation will have an estimated average of 14% copper content as well as payable gold and silver; the zinc concentrate flotation will have an estimated average of 51% zinc content.