DEPARTMENT OF MINES AND ENERGY Image positional only placement optional Washout feature in PPP 70/30 Daly River Management Advisory Committee - Katherine - 19 th September 2012 Mount Todd Department of Mines & Energy Management Activities

DEPARTMENT OF MINES AND ENERGY NT Government Commitment Continuous engagement and involvement of stakeholders through the Mount Todd Mine Site Rehabilitation Reference Group. Maintenance of the environmental operations of the site between 2000 and 2005, including substantial expenditure on site works and installation of critical infrastructure to manage the inventory of poor quality water on site. Brokering of the Agreement with the current operator, Vista Gold, to ensure an on- site presence for environmental management. Negotiation of the extension/ renewal of the existing Agreement with Vista Gold to support the work undertaken by the operator to further define the resource. Provision of significant funding for investigations to determine management and remediation options and to undertake works on site.

DEPARTMENT OF MINES AND ENERGY Brief Site History The site’s history can be broken into 3 distinct phases: Exploration & Mining (1986 to 2000); Northern Territory Government management (2000 to current); and Northern Territory Government Agreement with Vista Gold period (2006 to current).

DEPARTMENT OF MINES AND ENERGY Exploration & Mining (1986 to 2000) Exploration activities from 1988 to 1992 Phase 1 Heap Leach commissioned in late 1993 Phase 2 upgrade to milling and CIP circuit completed in late 1996 Pegasus placed the operation in Care & Maintenance 11/97 General Gold Operations (Multiplex) recommenced mining July th July 2000 General Gold appoints an administrator

DEPARTMENT OF MINES AND ENERGY NTG Management 2001 to 2006 Aerial view

DEPARTMENT OF MINES AND ENERGY NTG Management 2001 to 2006 Installed and operated pipelines and pumping equipment Maintained staff on site to manage water issues and carry out repairs and maintenance Weeds & fire management Approximately $5 million in direct costs In excess of $2.0 million in indirect costs (wages, vehicles, consumables, consultants studies etc) April 2005 set up the Mt Todd Mine Site Rehabilitation Reference Group

DEPARTMENT OF MINES AND ENERGY NTG / Vista Gold Agreement 5 years + 5 years + 2 years Agreement renewed for the second 5 year period in early 2011 after Vista presented its Preliminary Feasibility Study The agreement indemnifies Vista Gold against liability for pre-existing environmental conditions until they have an approved mining operation. NTG retails liability until then. Vista Gold became the authorised operator of the site under the Mining Management Act and has all of the responsibilities for the day to day operation of the site including managing environmental impacts. There has been a good level of co-operation between the NTG and Vista in managing the site to minimise off site impacts.

DEPARTMENT OF MINES AND ENERGY NTG Management 2006 to present

DEPARTMENT OF MINES AND ENERGY NTG Management 2006 to present 2006 to 2010 : Installed and operated gauging stations with telemetry Installed siphons at RP1 to manage releases Co-funded water treatment facility with Vista Gold Commissioned a range of consultancies to produce information to feed into a remediation plan Ongoing monitoring of water quality by DME’s Environmental Monitoring Unit Estimated to be approximately $1 million in direct costs and a further $1 million in indirect costs.

DEPARTMENT OF MINES AND ENERGY NTG Management 2006 to present Constructed diversion drains for the tailings dam and RP1 Reshaped the Waste Rock Dump to reduce infiltration Ongoing small scale water treatment (NTG/Vista partnership) Raising of the RP1 embankment and spillway Construction of a water balance model Design of an embankment raise for Batman Pit as a contingency Estimated to be approximately $2 million in direct costs and a further $0.5 million in indirect costs to present:

DEPARTMENT OF MINES AND ENERGY Diversion Drains Diverts 56 ha which is approximately 20% of the Tailings Dam’s catchment

DEPARTMENT OF MINES AND ENERGY Diversion Drains

DEPARTMENT OF MINES AND ENERGY Waste Rock Dump Reshaping

DEPARTMENT OF MINES AND ENERGY RP1 Embankment Raise Main embankment raised by 1.5 metres Spillway raised a corresponding amount Additional small embankment constructed on western side Purpose to allow more time for pumping to get on top of large events and prevent uncontrolled discharges, not as long-term water storage

DEPARTMENT OF MINES AND ENERGY Water Balance Model Allows DME to independently review information and run various scenarios

DEPARTMENT OF MINES AND ENERGY Batman Pit Embankment Raise Design

DEPARTMENT OF MINES AND ENERGY Boxing Day 2011 Event

DEPARTMENT OF MINES AND ENERGY Boxing Day 2011 Event 27 th Dec th Dec 2011