textos de practica para minas

7/31/2019 Textos de Practica Para Minas

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TEXTOS DE PRCTICA PARA MINAS

Mine closure planning involves planning effectively for the after-mining landscape all activities requiredbefore, during, and after the operating life of a mine that are needed to produce an acceptable landscape

economically. Closure performance refers to the activities near and after mine closure and how well activities

listed in the closure plan are carried out.The case can be made that a mine begins to close the day it opens. Decisions made during the mine planning

and development phase and even earlier, during the exploration phase have profound effects on the

ultimate closure plan, its cost, and the resulting landscape performance. These decisions need to be made

within a framework of closure planning to realize successful reclamation.

Activities related to closure planning often include: preparation of detailed drawings of disturbed landscape,

compilation of baseline information, discussions with regulators and stakeholders on end land use

considerations, crafting of supporting research programs, and preparation of budgets and schedules. For a

mine nearing closure, the closure plan takes the form of a decommissioning plan, and includes details and

selection of mitigative technologies (especially for acid rock drainage) and other specific reclamation and

closure activities.

A critical element of successful reclamation and of good closure planning is stakeholder involvement.

Generally, mines do a poor job of ongoing, meaningful stakeholder consultation, and many would benefitfrom professional assistance. A particularly useful consultation process involves forming a local committee to

provide guidance to one or more mines in the region in their reclamation and closure activities with a focus on

providing ongoing dialog with stakeholders and identifying the goals important to stakeholders.

The most important benefit of closure planning is identification of critical activities to achieve successful

reclamation. Closure planning usually identifies areas of needed research. It also identifies planning

constraints (and sometimes opportunities) especially identifying safe methods and locations for mine waste

storage. These plans provide some assurance that the mine is not painting itself into a corner and provide a

starting basis to estimate financial assurance levels important to both mines and regulators. It also forms a

base case against which future planning changes can be compared. Much of this work falls under the concept

of design for closure introduced 30 years ago.

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Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an orebody, vein or (coal) seam. Materials recovered by mining include base metals, precious metals, iron, uranium,

coal, diamonds, limestone, oil shale, rock salt and potash. Any material that cannot be grown through

agricultural processes, or created artificially in a laboratory or factory, is usually mined. Mining in a wider

sense comprises extraction of any non-renewable resource (e.g., petroleum, natural gas, or even water).

Mining of stone and metal has been done since pre-historic times. Modern mining processes involve

prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired

materials and finally reclamation of the land to prepare it for other uses once the mine is closed. The nature of

mining processes creates a potential negative impact on the environment both during the mining operations

and for years after the mine is closed. This impact has led to most of the world's nations adopting regulations

to moderate the negative effects of mining operations. Safety has long been a concern as well, though modernpractices have improved safety in mines significantly. Mining today is able to profitably and safely recover

minerals with little negative impact to the environment.

Steps of mine developmentThe process of mining from discovery of an ore body through extraction of minerals and finally to returning

the land to its natural state consists of several distinct steps. The first is discovery of the ore body, which is

carried out through prospecting or exploration to find and then define the extent, location and value of the ore

body. This leads to a mathematical resource estimation to estimate the size and grade of the deposit. This

estimation is used to conduct a pre-feasibility study to determine the theoretical economics of the ore deposit.

This identifies, early on, whether further investment in estimation and engineering studies is warranted and

identifies key risks and areas for further work. The next step is to conduct a feasibility study to evaluate the

financial viability, technical and financial risks and robustness of the project. This is when the mining

company makes the decision to develop the mine or to walk away from the project. This includes mineplanning to evaluate the economically recoverable portion of the deposit, the metallurgy and ore

recoverability, marketability and payability of the ore concentrates, engineering concerns, milling and

infrastructure costs, finance and equity requirements and an analysis of the proposed mine from the initial


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excavation all the way through to reclamation. Once the analysis determines a given ore body is worth

recovering, development begins to create access to the ore body. The mine buildings and processing plants are

built and any necessary equipment is obtained. The operation of the mine to recover the ore begins and

continues as long as the company operating the mine finds it economical to do so. Once all the ore that the

mine can produce profitably is recovered, reclamation begins to make the land used by the mine suitable for

future use.

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The Mine Development Process

Mine development is a complex long-term process that starts well before a mine is built and continues

well beyond when the mine is closed. During the exploration stage, the first step is a public outreachor stakeholder consultation program. A mining or exploration company usually begins this stagewhen it acquires or discovers a mineral project with economic potential or plans an initial work

program to test the potential of a mineral prospect.

In British Columbia, most companies understand that they must begin their consultation programsearly so that local communities, First Nations leaders and other stakeholders be involved in the project

by understand the scope and objectives of the work programs and the safeguards that will be

incorporated into these programs to protect the environment. Early consultation helps companies

understand local values and address issues of concern that may be raised by First Nations leaders and

other stakeholders. This two-way dialogue also helps the public understand that only a few prospects

ever become operating mines, and that all mine proposals must undergo a lengthy and rigorous

environmental assessment process open to broad public scrutiny.

The consultation process usually increases as the project advances to the stage where a preliminary

economic assessment (or scoping study) is completed. This study is the first time that current

economics are tied to the project. Following the preliminary findings of a scoping study, a company

will move to the pre-feasibility and feasibility stages, and may at the same time, enter the

environmental assessment and permitting process. This stage provides more specific findings about the

project's design and economics than the scoping study. Government agencies, environmental groups

and non-governmental organizations will also carefully scrutinize any mine project that advances to

this advanced stage of environmental assessment and permitting. Mining companies must consult and

engage with a broad range of stakeholders in order to develop public understanding and support for

their projects over time, and thereby gain a "social license" to operate.

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MDT deploys first underground WIRELESS monitoring system!The first system was successfully deployed this week with real-time data streaming to surface.

Newtrax Technologies (www.newtrax.com) customized their standard wireless node to read MDT's

SMART instruments (up to 3 instruments per node!). The underground network (MineTrax) runs at

900MHz, forms a self-identifying, self-healing mesh and runs for years on batteries! MineTrax can

also be used for men and vehicle tracking, and ventilation on demand. Email [email protected] for more

information on our wireless instruments, and check out the Newtrax website for details:

www.newtrax.com

Nickel Rim Mine: Brad Simser, Xstrata Nickel
http://www.newtrax.com/mailto:[email protected]:[email protected]://www.newtrax.com/http://www.newtrax.com/mailto:[email protected]://www.newtrax.com/


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Xstrata Nickel recently used MDT's instruments at their Nickel Rim Mine to monitor ground

displacements around a large garage excavated 1480m below surface.

The final opening is 16 metres wide by 11 metres high and 75 metres long. It was excavated in three

passes: 10m wide x 6.5m high; slashed to 16m x 6.5m high; and finally breasted to 11m high by 16m

wide. In the first pass, they employed MDT's 10 metre MPBX instruments to monitor movement

caused by the second and third pass mining. "We needed the instruments to make sure that groundsupport systems were holding as we expected" said Brad Simser, Ground Control Engineer atXstrata Nickel. "MDTs instruments did the job perfectly."

Xstrata also used three short and three long MPBXs for long term monitoring in the final back of the

excavation. With MDTs instruments in place, Xstrata can monitor any minor movements in the back

and decide if they are small issues or more deep seeded concerns. "MDT made it easy to addresssmall problems before they became major issues and we should be able to avoid the extremelydifficult task of fixing an 11m high back."

Eventually the instruments will be hooked up to MDT's wireless monitoring system by Newtrax andget the readings in real time on surface.

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