Location

Access to the Espérance mine is by river, via the Maroni River which borders the border with Suriname. An aviation runway of nearly 1000m provides easy access to the site.

The operation, which has been completed since 2010, was an open pit mine (OFM). It was carried out using Hyundai 450 mechanical excavators (4 units) and the transport of the ore by Terex TA35 articulated dumpers (4 units). The company only exploited soft saprolitic materials that do not require explosive felling.

The ore was processed in two stages: crushing and grinding in two closed-circuit ball mills. The gold recovery was then ensured by centrifugal concentrators of type Knelson KC 48.


esperance cme

History

Esperance Creek has been known since 1890 for its wealth of gold. Various works were undertaken by the former gold miners who left traces of their passage on site: tunnels, railway, steam engine, etc.

During the inventory of Guyana’s mineral resources, the BRGM will carry out significant work covering the work of the elders. The results are surprising, showing a geochemical anomaly more than 2 km long and 500 m wide. The three cored boreholes drilled in the process show a mineralization rooted in saprolite and hard rock up to at least 150 m of depth.

The deposit then emerges as a priority N°1 of the inventory.

At the end of the 1980s, Gérard Ostorero discovered this project with interest and quickly gathered the necessary resources to put it into operation. He founded Compagnie Minière Espérance in 1991, after obtaining a personal research permit.

Mining begins with the alluvial resource, which is abundant and provides funding for the development of the Espérance primary mine.

In 2013, the Espérance mine gave its name to a rock found on the planet Mars by the rover Opportunity; this rock is proof that the planet Mars was indeed rich in water and conducive to life in the past. The rock is called Espérance because of the presence within the mission of a member who has carried out research on the site of the Espérance mine, but also because this discovery gives hope of a possible life form on Mars.
New York Times Article:  here

Article complet :  here

Geological context

The Espérance deposit is located in the western part of the green rock belt (greenstone belt) in northern Guyana. It belongs to a larger group, called the Shield of Guiana, formerly connected to the West African Shield.

In Espérance, mineralization took place in tectonic contact between the Maroni sedimentary basin and a set of granite massifs. The basin is formed by detritic series, resting in discordance on a volcano-sedimentary base (series called «Paramaca»). The affected area is strongly deformed by the shear movements that developed in contact with the granites.

The gold is carried by a quartz filonian network presenting a stockwerk geometry and encased in the detritic series. The latter consist mainly of rolled sandstone and conglomerate sandstone. Gold is present either in association with pyrite, or free or included in quartz. Mineralization is very poor in other elements usually accompanying gold: silver, arsenic, etc.

Photo historique

 

Vestige (mine d'Espérance)


esperance  coupe

The Nouvelle Espérance ERP

Since 2010, the CME has held an exclusive research permit (ERP) called «Nouvelle Espérance». It covers an area of 175 km² around the main deposit and aims to highlight the presence of satellite mineralizations in a similar geological context. In particular, it encompasses several BRGM prospects containing significant geochemical anomalies, as well as numerous creeks exploited for alluvial gold.