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ESIA and supporting studies of Perama Gold project in Northern Greece

​​ESIA and supporting studies of Perama Gold project in Northern Greece


Country: Greece

Region: Perama, Thrace
Client: Thracean Gold Mining and Industrial S.A.
Start date: June 2009
Completion date: December 2011
Duration of assignment (months): 30
Name of associated Consultants: ECHMES LTD

 

Narrative description of Project:


The Perama Gold Project is aiming towards the exploitation of the Perama gold deposit for the production of gold/silver bars (DORÉ), with Au concentration ~40%. The auriferous ore deposit of Perama is located on east boundaries of the Maronia fault, hosted within a package of volcanic sandstone overlying volcanic andesitic breccias.


A closed type open pit mining method with selective ore recovery is the most appropriate method for the exploitation of Perama Hill gold deposit.


The selection of the most appropriate metallurgical treatment method was based on environmental, technical and economical criteria based on the results of a series of experimental tests, performed on representative ore samples by specialised and acknowledged firms of abroad, with industrial experience on the treatment of similar ore deposits. The selected metallurgical process aims at the maximization of the precious metal recovery and the effective protection of the environment.


The metallurgical process involves:

  • Primary crushing using a jaw crusher.
  • Secondary and tertiary crushing using short-head cone crusher
  • Grinding with a single ball mill in closed circuit with cyclones.
  • Leaching of ground ore with a sodium cyanide solution and blowing oxygen, in the presence of activated carbon, for gold recovery (Carbon In Leach, CIL).
  • Elution of gold and silver from loaded carbon using an elevated pressure and temperature leach method and electrowinning of gold and silver from pregnant solution.
  • Calcination of loaded cathodes and smelting of the calcine to produce doré bullion.
  • INCO cyanide destruction process (SO2 + oxygen) of CIL tailings
  • Liberation of water using thickener and filtration system to produce filter cake of approximately 85 wt% solids.
  • Transfer by tracks and placement into an appropriate waterproof Mine Waste Management Facility (MWMF)

Thus, the main installations of the Project involve the Open Pit Mine, the Process Plant and the Tailings Management Facility. Considering the fact that the treatment process is a closed circuit and the filter cake is dewatered, the demand for water is limited to the very low losses due to evaporation. The process water that is needed to cover the losses is anticipated to be a mixture of surface run off water in the project area and underground water pumped from borehole in the area. It is noted that in order to operate the project in a closed circuit, constant supervision of the water resources in the collector sump is required, by evaporation of water via a sprinkler system installed on the surface of the filter cake in the MWMF.

Description of actual services provided by Enveco within the assignment:


The following tasks have been covered:


Task 1: Definition and environmental assessment of alternative methods and sites
Task 2: Description of the existing characteristics of the Human and Natural environment in the wider project area, focusing in parameters that may be impacted by the construction, operation and rehabilitation of the project
Task 3: Detailed Assessment and evaluation of the main environmental impacts of the proposed project during the stages of construction, operation and rehabilitation
Task 4: Proposed mitigation measures for the abatement of the impacts
Task 5: Proposed environmental terms which should be followed during all phases of the project
Task 6 : Supporting Studies. In the framework of the contract the following tasks were elaborated:

  • Baseline Studies (- Soil Survey study, - Flora baseline survey study)
  • New studies due to new legal framework (Waste Management Plan (according to Directive 2006/21), - Update of Evaluation of Potential Risks and Anticipated Measures for their Prevention and Mitigation)
  • Specialized Assessment Studies (Revised air quality assessment, Revised evaluation of the noise propagation
  • Other studies required for the overall permitting of the project (Creek Delineation Studies, Update of industrial liquid effluents and sewage study)