Hemlo

Overview

The Hemlo gold mines property consists of David Bell, an underground mine, and Williams, an underground and open pit mine, located approximately 350 kilometres east of Thunder Bay, Ontario, Canada.

Gold was discovered in the Hemlo area in 1869 but it wasn't until the 1940s that trappers, prospectors, geologists and investors staked claims covering some newly discovered occurences that later on turned to be the claims from where gold would be extracted in modern times by the Hemlo mines.

The Williams and David Bell mines share milling, processing and tailings facilities where ores from the two mines are co-mingled and fed to a standard grind, leach and carbon-in-pulp extraction mill.

Barrick Gold Corporation is the 100% owner of the Hemlo mines. Franco Nevada has both a 3% NSR royalty and a 50% NPI royalty on a portion of the western down-dip underground extension of the Hemlo ore-body. 

In 2011, Hemlo mining operations produced 227,000 ounces of gold. As of December 31, 2011 Hemlo’s proven and probable mineral reserves contained 1.4 million ounces of gold.

A feasibility study is expected to be completed in the second part of 2012 on a newly identified 1 million ounces gold resource that would add to the mine life another 7 years.

Location

The Hemlo property consists of David Bell, an underground mine, and Williams, an underground and open pit mine, located approximately 350 kilometres east of Thunder Bay in the Canadian Province of Ontario.

Ontario is the most populous of the Canadian provinces. It is located in the eastern part of the country. The city of Marathon lies 40 km west of the Hemlo area and it was founded as a railroad town. Nowadays it boasts a population of over 3,300 permanent residents and an economy based on forestry and gold mining.

First gold occurences were discovered in the Hemlo area in 1869. In the 1940s prospectors and trappers staked more gold occurences and then sold some of them to Dr. Jack K. Williams of Maryland (his name would be later on attributed to a Hemlo gold mine). In 1979 more claims were staked by local prospectors and an interested party optioned them; drilling and geological research were conducted by a geologist named David Bell who would also borrow his name to another Hemlo gold mine. Drilling soon discovered the main Hemlo deposit and a gold rush involving over 180 companies ensued.

Geology & Mineralization

The Hemlo operations are located in a small east-west trending Archean greenstone belt in central Ontario known as the Hemlo zone. The Williams mine is located at the western end of the Hemlo zone, the David Bell mine is located at the eastern end of the Hemlo zone. 

The Hemlo gold camp has been producing gold for over 25 years and is located just off the Trans-Canada highway near Marathon, Ontario.

The Williams and David Bell ore bodies lie at the contact between overlying metasedimentary rocks and underlying felsic metavolcanic rocks.

 The Williams ore zone dips north at 60-70 degrees and the David Bell ore zone dips north at 50-60 degrees. The ore zones continue to approximately 1,200 metres below the surface and vary in width from 45 metres to 1 metre at Williams and from 15 metres to 1 metre at David Bell. The ore at both mines is hosted by three principal rock types, feldspathised porphyry, muscovite schist and biotite fragmental, and is characterized by gold, pyrite, molybdenite, and barite and various arsenic, mercury, and antimony mineral species. Both main ore bodies are composed of fine grained quartz-feldspar rock with gold occurring as finely disseminated particles within the groundmass as well as with pyrite grains. 

As of May 2012, Barrick announced that exploration efforts managed to indentify a 1 million ounces gold reserves that would extend open pit mine life by up to 7 years.

Mining & Operation

The Williams and David Bell mines share milling, processing and tailings facilities. Ores from the two mines are co-mingled and fed to a standard grind, leach and carbon-in-pulp extraction mill.

Present day mine life is 2018 but 1 million ounces gold would be added to the reserves in 2012, and a feasibility study is expected to be completed in the second part of the year. The new reserves could extend the mine life of the open pit mining operation to 2025.

Processing

Milling, processing and tailings facilities. Ores from the two mines are co-mingled and fed to a standard grind, leach and carbon-in-pulp extraction mill.

Environment & Community

Hemlo mining operations are providing opportunities for resdients of two nearby First Nations by creating a framework to train them for present and future mining employment. The mine also supports their businesses and trains them in how to do business.

In 2010, Hemlo mines contributed $800,000 in a variety of donations to local communities.