WE ARE PUSHING OUR MINES TO ACHIEVE EVER GREATER LEVELS OF EFFICIENCY AND PRODUCTIVITY THROUGH A CONTINUOUS CYCLE OF OPTIMIZATION, MAKING PROASIANGOLD ONE OF THE LOWEST-COST GOLD PRODUCERS IN THE INDUSTRY
The Mining Process
For many years, South Africa was the world's most important gold producer. It was the world's main source of gold mining from the 1880s through 2006. In 1970, for example, South African gold output accounted for nearly 79 % of all gold produced worldwide. However, China surpassed South Africa in 2007, making it no longer one of the top three countries. China, the United States, and Australia are the top three gold producers in the world, with South Africa and Russia rounding out the top. Today, China is the dominant gold producer.
Exploration businesses are at the start of the process. There are junior development companies, minor gold mining companies, mid-tier gold mining companies, larger multi-mine gold mining corporations, and royalty companies. In the gold mining sector, every sort of company has a function to play. Each one has its own corporate profile and investment opportunities.
Exploration
Gold exploration is a time-consuming, difficult, and scientific procedure. Exploration may be time-consuming and costly, with only one in every 3,000 finds advancing to mine development and only 10% of the world's gold resources possessing enough gold to mine. While gold can be discovered in concentrations of two to four parts per billion all over the planet, we need to find locations with concentrations of 2,000 to 3,000 parts per billion to be lucrative.
So how do our exploration teams locate future large-scale projects?
Exploration is the first step. However, because gold veins are often only a few feet wide and curve over the Earth's geography, identifying and exploring the area among thousands of square miles of land is incredibly challenging.
Obviously, starting in gold-bearing areas makes logic, but there are almost 900 such spots around the world to select from. It is ideal to start looking at less-explored areas first, but we are also seeking exploration partners and/or buying junior mining firms to speed up the process.
ProAsianGold uses several methods to reduce the size of land to explore:
Drilling is carried out once a target location has been identified and geological, geophysical, and geochemical data suggest a high chance of a deposit. Drilling helps in determining the type and grade of minerals present in the ore.
Production geologists employ data from sampling, testing, mapping, and observing to find the most efficient and effective mining procedures and to assess the ore's grade. The grade of gold and silver is measured in grams per ton. The grade of copper is expressed as a percentage. Knowing the grade is crucial for determining which rocks are delivered to the processing facility and which are sent to the waste rock storage area.
Mine engineers may select mining methods, design blast patterns, design dig patterns, and maximize the safety and efficiency of production, as well as identify how the ore should be processed by using this data and advanced computer algorithms to more correctly characterize the orebody.
Drilling and sampling data are often used by geologists to locate moist areas. In both open pit and underground mines, water can be a big issue. We can reduce safety hazards, costs, and production delays by avoiding or planning for regions with high water content in advance.
Gold demand worldwide from 2007 to 2017 (in metric tons)
World gold production by year in mines from 2005 to 2017 (in metric tons)
Designing and Constructing a Mine
There are two types of mine designs for mineral mining: surface (open pit) and underground.
Surface
Surface mines are favored when the ore body is shallow and consistent, and they are created by digging one layer at a time into the Earth's surface. The completed mine is shaped like a cone.
We start by drilling holes in the ground and then filling them with explosives. Blasting breaks up the rock, which is then loaded into massive haul trucks with big shovels and front-end loaders. Waste rock is brought to a different region for storage while rock containing gold, copper, and other important minerals is carted away for processing. Waste rock areas are later repaired.
Dewatering the mine is required as we dig deeper to guarantee that the water level remains below the pit floor. Thousands of gallons of water are pumped out of the hole every day. Excess water is treated before being released into surrounding rivers or lakes.
In and around the open pit, there is a substantial amount of monitoring to be performed:
Underground
Minerals and metals are extracted from deep within the Earth via underground mines. To get to the minerals in an underground mine, we dig a tunnel. This might be a straight vertical tunnel, known as a shaft, or a spiraling downward tunnel, known as a decline. We dig other tunnels to get to the ore from the shaft or decline. We also mine tunnels to give sufficient ventilation and escapes in the event of an emergency.
Drilling and blasting are used to mine the tunnels and mineral deposits. The ore is subsequently broken up and sent to the surface to be processed. Waste rock can either be hauled to the surface or left in the mine to fill in gaps.
Once we have removed all of the materials from inside the tunnels, we work with them to ensure that they are safe. The sort of ground support required is determined by the stability of the ground and the length of time the tunnel will be in operation. Engineers identify these factors ahead of time so that the mine can be designed for optimal safety and value.
Rock bolts or split sets, which are driven into drilled holes to exert pressure on the surrounding rock, which maintains it intact, can offer ground support. To increase the strength of rock bolts, chemicals or grouts are occasionally used. Wire mesh is also installed to prevent smaller rocks from falling.
More support is provided by high-pressure spraying of Shotcrete (a mortar/concrete mix) on the tunnels' walls and backs. We backfill each stope with a cement mixture when we finish mining it.
Underground mines are more dangerous and restrict the size of equipment that may be utilized, but they produce less environmental damage.
Operating a Mine
We utilize strict controls to prevent or mitigate any environmental problems when running a mine. All environmental aspects, including management, monitoring, maintenance, training, and action plans, are incorporated into an overarching framework as an integral component of mining operations with our environmental management systems.
ProAsianGold will follow all applicable laws, regulations, and other legal obligations at all times. We also employ an internal management system that incorporates a global set of performance standards to give a set of acceptable performance requirements within a framework of continuous improvement, in addition to this mandate.
Ore Processing
Ore is transported from open pits or underground operations to processing plants using haul trucks. Some ores may be stored in order to be processed later. Waste rock storage sites are used to store rock that is too expensive to mine. The processing procedure is determined by the grade and kind of ore. The cost and methods used to extract gold are also influenced by the ore's geochemical composition, which includes its hardness, sulfur content, carbon content, and other minerals.
Processing methods
We process ore using the following methods:
Alternative Ore Processing
In some processing plants, we apply alternate gold recovery technologies to satisfy differing ore properties or other requirements. Refractory ore, for example, is ore with a high concentration of sulfide minerals or carbon (or both). Refractory ore defies conventional processing because rich sulfide minerals confine gold particles, making it harder for cyanide to access and extract the gold.
Heating – High temperature, high pressure, and/or oxygen are required to leach gold from refractory ore. ProAsianGold uses either an autoclave or a roaster to treat refractory ore.
Before any leaching takes place, an autoclave is employed. The slurry is heated and then fed into an autoclave, where high-pressure steam, water, and oxygen are used to chemically oxidize the sulfide material. The slurry is then chilled and returned to the extraction stage.
A roaster, an extremely high-temperature oven that is often used instead of an autoclave if the ore to be processed includes a substantial quantity of organic carbon, is an alternative to an autoclave. Roasting combines heat and air to convert organic carbon to fuel and to burn sulfur from ore that has been heated to a high temperature.
Heap leaching – In heap leaching, crushed ore is dumped into heaps, to which a weak cyanide solution is applied by drip feeders. In the cyanide solution, the gold dissolves. To ensure that no solution leaks into the environment, the entire heap leach area is lined with high-duty liners. The gold-cyanide solution is then collected in ditches and ponds and sent to a recovery plant.
Flotation – a technique for separating minerals based on their capacity to cling to air bubbles.
By changing the chemicals, flotation can be utilized for a variety of materials. It is utilized for copper recovery and, in a small number of cases, gold processing at ProAsianGold.
While the slurry is in small tanks called flotation cells, air bubbles are introduced to it. To aid the process, we add various chemicals to the slurry. The targeted minerals adhere to the bubbles and rise to the surface, forming froth. The froth from the tank overflows, and it is removed and delivered to the next stage of processing.
Gravity circuit – Prior to being leached, coarse gold is recovered via a gravity circuit. Gravity circuits work on the same principles as gold panning: coarse gold is heavier than other materials and will sink to the bottom, allowing it to be extracted (gold is 19.3 times heavier than an equal volume of water).
ProAsianGold is dedicated to leaving a positive impact in the communities and environments where we do business. This commitment includes, among other things, designing an integrated closure strategy that addresses community and environmental concerns, as well as restoring affected land for useful use once our mines close.
Closure and reclamation planning begins in the early stages of project development, before operations begin at a new site, and continues throughout the mine's development. Our goal is to cause the least amount of land disturbance possible throughout our exploration activities. We restore all affected land, with the exception of roadways, which are left untouched if the local community or government requests it.
Environmental Closure
During the mine's life, disturbed land is gradually restored. Our Closure and Reclamation Technical Team creates and implements a system that ensures that the approach to site closure and reclamation, including costs, is evaluated and reported regularly throughout the mine lifecycle.
ProAsianGold aims to use a novel scientific way to treat mineral waste generated during precious metals extraction when establishing and implementing reclamation strategies. We pioneered solutions at several of our sites that have since been disseminated in the industry as scientifically proven ways to mine site closure and reclamation around the world.
Our rehabilitation and closure plans are designed to ensure:
We gradually rehabilitate portions of disturbed land in the mining region for future purposes such as ranching, recreation, or wildlife habitat protection in order to restore the landscape for future uses such as ranching, recreation, or wildlife habitat conservation, which has a variety of benefits:
Social Closure
The closure of a mine can have a substantial influence on the surrounding community. As a result, we work with our stakeholders early in the project planning process to guarantee that the value created throughout the mine operation is transferred into long-term community activities. Over the life of the mine, sites must establish a procedure for assessing and updating closure plans with external stakeholders on a regular basis.