GLOSSARY OF MINING TERMS

 

Access arrangement
An access arrangement is required between a landowner and a miner to determine the conditions under which minerals exploration or mining can occur on a defined area of land. On private land, this arrangement will be determined by negotiation between the landowner and the miner.

On publicly owned land this arrangement will be determined on terms laid down by the relevant minister, or his or her departmental staff, subject to criteria set down in the Crown Minerals Act. For example, on public conservation land, the arrangement will be determined by the minister of conservation, or his or her departmental staff, and by the energy and resources minister, as will a decision over whether or not to grant access.


Alluvial gold mining
Alluvial gold mining is the practice of recovering gold from alluvial deposits. These deposits occur as layered accumulations of gravel and sand as a result of the erosion of mountains through weather and time. The deposits accumulate in terraces, valley floors, riverbeds, and beach sands.


Alluvium
Alluvium refers to material (gravels, sands, silts) laid down by freshwater systems, and accumulating as outwash at the feet of glaciers, mountains, and on flood plains.  


Aggregate
Crushed rock, gravel, or sand used for road making, construction, and other infrastructure, and other industrial applications, eg the making of concrete.


Amalgamation (of metals)
Amalgamation refers to the process of extracting metals (as native gold and silver) from their ores by the addition of small quantities of mercury to the stamping or grinding unit, or to an ore concentrate, so that the resulting amalgam is caught on mercury-coated copper plates from which it is then scraped, the precious metals in it being recovered by distilling off the mercury under controlled conditions.

This process can be used to refine impure gold to a pure state.


Anthracite
A hard, greyish or blackish metallic-looking substance, anthracite is the highest rank of coal, containing the highest levels of fixed carbon, and lowest levels of moisture, volatile matter, and impurities.


Assessment of environmental effects
This term applies to the information required to be given to the Department of Conservation under the Crown Minerals Act for miners accessing public conservation land via an access arrangement, and also to the information that must be given to a district or regional or unitary council under the Resource Management Act, to inform decision makers and regulators of the environmental effects of a mining operation prior to land access or resource consents being granted.

The AEE forms the basis for determining methods for managing environmental effects, to flow into conditions of access arrangements, and/or resource consents.

Bench(ing)
When opencast mining, as with other forms of earthmoving, a bench refers to a wide ledge, often several metres in width. The establishment of a bench (or series of benches) is used to stabilise the sides of a pit and prevent or reduce the severity of any collapsing of exposed and excavated walls in the pit of a mining operation. Once established, a bench will catch any debris that falls down on to it from the face above. 


Bituminous coal
Referring to coal of a high rank (having high levels of fixed carbon, and lower levels of volatile matter, moisture and impurities) to qualify as bituminous. This term is not to be confused with “bitumen”, which is a heavy and thick type of petroleum. The main uses of bituminous coal today are for the production of coke (a feedstock for manufacturing iron and steel) in coke ovens, and intrinsic to the production of iron and steel from iron ore, as a metallurgical or mineral chemical input. For this reason, bituminous coal is often referred to as “coking coal”.


Blacksand
Blacksand, on the West Coast, refers to black sands found on beaches and likely to bear very fine gold that can be recovered from beach sands via “black sanding”, or “black sand mining”.


Bulldozer
A large tractor with self-laying caterpillar tracks, and a broad, curved upright blade at the front for clearing ground and moving earth. Also known as a dozer.


Buller District
The northernmost of the three districts of the West Coast region, stretching from Kahurangi Point in the north, to the Punakaiki River in the south.

 

Carbon dioxide
Carbon dioxide (CO2) refers to molecules that are one part carbon, two parts oxygen. It is the world’s largest source of man-made greenhouse gas, and the largest contributor to climate change/global warming. 


Carbon dioxide equivalent
Carbon dioxide is the largest source of greenhouse gas, but not the only source. It sits alongside methane, nitrous oxide, and others. To standardise these gases (and give a common unit of account), the term “carbon dioxide equivalent” (or CO2e) is used.


Coal
The term used to refer to all blackish/brownish sedimentary rock formed of plant matter and other organic materials that under the pressure of burial below overlying rock, and over millions of years, becomes a combustible fuel source of predominantly carbon. The rank of coal ranges from lignite, through to sub-bituminous, bituminous, and anthracite.


Coke
A material, or solid fuel, made by heating coals in the absence of air to drive off moisture and volatile components. This produces a fuel that performs well in a blast furnace used in making iron from iron ore, the first step to steelmaking.


Coking coal
Coking coal refers to coals, mainly of bituminous rank, that lend themselves to the production of coke.

 
Conservation Act

The Conservation Act 1987 is the one of the Acts of Parliament in New Zealand governing public conservation land, which makes up about one-third of the land area of New Zealand.

Mining activities (prospecting, exploration, and mining) on public conservation land must be carried out in a way that is consistent with the Conservation Act (and also comply with land access provisions under the Crown Minerals Act).


Crown Minerals Act
The Crown Minerals Act 1991 refers to the legislation that governs mineral resources in New Zealand, which are owned by the Crown.

Its purpose is to promote the prospecting for, exploration for, and mining of Crown owned minerals, for the benefit of New Zealand. 

 

Department of Conservation
The agency of the New Zealand government tasked with administering public conservation land on behalf of all New Zealanders, and enforcing and giving effect to the Conservation Act, and other conservation legislation.


Digger
This refers to earthmoving machinery, also known as an excavator, consisting of a boom, dipper, bucket and cab on a rotating platform known as the “house”. The house sits atop an undercarriage with tracks or wheels.
Dredge
A dredge is used in goldmining for the recovery of alluvial/placer gold from alluvial gold deposits, particularly those that are found underwater (i.e. in rivers) or artificial and temporary ponds. A dredge will consist of a series of steel buckets on a bucketline at the front of the dredge. Running in a circular and continuous motion this will produce a constant flow of material, which is then further refined using a combination of water and gravity, before the final stages of producing pure gold.


Electricity and energy
In the context of New Zealand’s electricity and energy mix, as well as the proportion of which comes from renewable sources, the terms “electricity” and “energy” are sometimes used interchangeably.

Electricity refers to all forms of electrical energy, which in New Zealand is produced overwhelmingly from renewable sources such as hydro, geothermal, wind, and to a lesser extent solar and biofuels. Non-renewable sources of electricity generation are predominantly gas and coal.

Electricity is only part of the wider energy sector, which includes transport (largely powered by oil derivatives such as petrol and diesel), manufacturing (powered largely by gas and coal, but also by electricity and wood fuels), industrial processes and product use, among others.

Whereas 80-90% of New Zealand’s electricity comes from renewable sources – the fourth highest percentage in the OECD – only 30-40% of primary energy (total energy) in New Zealand comes from renewable sources.


Exploration
Exploration, as defined by the Crown Minerals Act, refers to any activity undertaken for the purpose of identifying mineral deposits or occurrences and evaluating the feasibility of mining them. It includes any drilling (of rock core), dredging, rock sampling, or excavations (whether surface or subsurface) that are reasonably necessary to determine the nature and size of a mineral deposit or occurrence. To explore has the corresponding meaning, and an explorer is a person who carries out the activity.


Exploration permit
A minerals exploration permit (MEP) under the Crown Minerals Act permits the holder to undertake exploration activities, subject to conditions.

It does not confer land access, which must be obtained separately by agreement with the landowner, nor does it confer a resource consent. 


Garnet
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Most commonly red, they can be of a wide range of colours, and are found in heavy mineral sand and alluvial deposits in areas of the West Coast.


Gold

Found on the West Coast in either alluvial or hard rock deposits, gold is a precious metal with very high exchange value (valued in recent years at about NZ$3,000 per ounce).

It is used in technology, jewellery, and by central banks and investors as a store of value, or as a hedge in financial markets

Gold screen
A gold screen is a mechanical plant used to refine gold concentrate from alluvial deposits, with components that in different ways use the force of gravity, in combination with water, to separate nuggets and flakes of gold from lighter gravels and sands. 

This can involve a rotating mesh trommel or drum, jigs which operate in a pulsating motion, and riffles which lead to an accumulation of gold concentrated in heavy mineral sand on tables.

This gold is then further refined until it can be melted down as pure gold.


Greenhouse gas emissions
The term greenhouse gas emissions refers to the release of any manmade gas into the atmosphere, which has a climate warming or “greenhouse effect”. This includes, but is not limited to, carbon dioxide, methane, nitrous oxide, and other gases.


Greenstone

The New Zealand English word for pounamu, a stone found in similar deposits to alluvial gold, in the river systems of the West Coast region.

Specifically, it encompasses the mineralogy terms, nephrite and bowenite, and is sometimes misleadingly referred to as jade, which is a different mineral.  


Grey District


Grey District is one of three districts in the West Coast region and comprises the area of the West Coast between the Punakaiki River in the north and the Taramakau River in the south.


Hard rock mining
The recovery of gold trapped in veins of quartz (known as reefs) is known as hard-rock mining. It involves the recovery of ore, in the form of gold-bearing quartz, by either opencast or underground mining methods, and then the milling or other processing of quartz to extract gold from the host rock, and separate and refine that gold into a pure gold.


Health and Safety at Work Act
The Health and Safety at Work Act 2015 is the legislation in New Zealand that governs workplace health and safety, including in the mining industry. This legislation was passed following the explosion of the Pike River Mine in 2010, which resulted in the deaths of 29 men working at this West Coast underground coal mine at the time of the incident.


Ilmenite
A form of iron oxide, also containing titanium, ilmenite is found on the West Coast in heavy mineral sands. It is a weakly magnetic black or steel-grey solid and is globally a major source on processing of titanium dioxide, which is used as a pigment in paints, printing inks, fabrics, plastics, paper, sunscreen, food and cosmetics.


Kilotonne
A unit of measurement referring to one thousand tonnes or metric tons (a kilotonne). This is often the unit used when measuring greenhouse gas emissions as carbon dioxide equivalents. For example, New Zealand’s gross greenhouse gas emissions are about 80,000 kilotonnes of CO2e, more commonly expressed in this case as 80 million tonnes.


Lignite
The lowest rank of coal, lignite is soft and brown, with the lowest rank (percentage of fixed carbon), high in moisture, as much as 50% by weight, and in some instances visible plant structures can be observed.

Used as a source of energy, and found mainly in Southland and Otago, it is only economic to transport lignite short distances from mines to customers.

The precursor to lignite is usually peat, a soil material rich enough in organic matter, that on drying can be used as a fuel.


Limestone
Sometimes colloquially referred to as “lime” (which is calcium oxide, strictly speaking), limestone is a sedimentary rock consisting mainly of the bones and shells of tiny marine fossils made of calcium carbonate. Rocks containing more than 50% calcium carbonate are considered to be limestone.

Limestone is used mainly in a finely crushed form as an agricultural fertiliser, and for roading aggregate. It is also vital for the manufacture of cement.


Makaawhio
One of two Ngāi Tahu tribes on the West Coast (the other being Te Rūnanga o Ngāti Waewae), Te Rūnanga o Makaawhio has rohe extending from Piopiotahi (Milford Sound) north to the Poerua River (near Hari Hari), and a shared rohe with Te Runanga o Ngāti Waewae from the Poerua River to the south bank of the Hokitika River.

The marae of Te Rūnanga o Makaawhio, is at Mahitahi (near Bruce Bay) in South Westland.


Metallic mineral(s)
This includes compounds of aluminium, chromium, copper, gold, iron, lead, manganese, mercury, molybdenum, nickel, platinum, silver, tin, titanium, tungsten, uranium, vanadium, and zinc.

 

Metallurgical coal
This term applies to coals used in the manufacturing of iron and steel, which includes but is not limited to bituminous coals used to produce coke. The West Coast produces and exports more than 1 million tonnes of bituminous coal annually.

The term can apply also to sub-bituminous coals, such as those produced in the Waikato for use in a unique process at the Glenbrook steel mill in South Auckland.


Mineral
The Crown Minerals Act defines a mineral as a naturally occurring inorganic substance beneath or at the surface of the earth, whether or not under water; and includes all metallic minerals, non-metallic minerals, fuel minerals, precious stones, industrial rocks and building stones, and a prescribed substance within the meaning of the Atomic Energy Act 1945 (eg uranium or derivatives).


Mineral sands
Mineral sand resources on the West Coast contain minerals including ilmenite, garnet, gold, zircon, and monazite among others.  


Mining

In a legal sense, mining refers to the recovery of any minerals in New Zealand from their natural state, or to take, win, or extract, “by whatever means” (Crown Minerals Act), a mineral existing in its natural state in land; or a chemical substance from a mineral existing in its natural state in land; and includes— the injection of petroleum into an underground gas storage facility; and the extraction of petroleum from an underground gas storage facility; but does not include prospecting or exploration for a mineral or chemical substance.


Mining permit
A mining permit refers to a minerals mining permit (MMP) granted under the Crown Minerals Act. It grants a property right to a mineral but does not by itself grant the right to recover the mineral. To do that, a miner or permit operator will need both land access to the land beneath which the mineral is located, and resource consent and potentially other environmental approvals to carry out the mining operation.


Ministry for the Environment
The Ministry for the Environment is, among other things, the government agency responsible for the Environment Act and the Resource Management Act.


Monazite
Monazite is a primarily, reddish-brown phosphate mineral that can contains rare earth elements. Due to variability in composition, monazite is considered a group of minerals, and often occurs as small, isolated crystals.

Monazites are found in some heavy mineral sand deposits on the West Coast.


Ngāti Waewae
Te Rūnanga o Ngāti Waewae (sometimes Te Rūnaka o Kāti Waewae) is one of two Ngāi Tahu tribes on the West Coast (the other being Te Rūnanga o Makaawhio).

Ngāti Waewae centres on the Arahura River and Hokitika and extends northwards from the north bank of the Hokitika River to Kahurangi Point and inland to the Southern Alps / Kā Tiritiri o te Moana, together with a shared interest with Te Rūnanga o Makaawhio in the area situated between the north bank of the Poerua River and the south bank of the Hokitika River.

New Zealand Petroleum and Minerals
A branch of the Ministry of Business, Innovation and Employment, New Zealand Petroleum and Minerals (NZP&M) is tasked with giving effect to the Crown Minerals Act on behalf of the Minister of Energy and Resources.

The agency and the staff working for NZP&M are responsible for, among other things, the allocation of minerals prospecting, exploration and mining permits under the Crown Minerals Act.


Opencast mining
As opposed to underground mining, open cast mining involves exposing a mineral resource (coal, a gold-bearing quartz reef, gold-bearing sands and gravels) by digging down through and removing layers of unwanted material (overburden or waste rock) to recover the resources below.


Overburden
This term refers to the layers of earth and sediment overlaying a desired resource (coal, gold, rock, limestone etc) trapped beneath the ground above. Overburden is removed during the lifetime of the mine, and then used as material for earthworks as part of mine closure, restoration, and rehabilitation.


Ounce
A unit of measurement often used when discussing quantities of gold. Specifically, the term refers to a troy ounce, eg in the case of gold, silver or platinum. A troy ounce = 31.103 grams. One kilogram equates to around 31 ounces (oz). An ounce of gold works out to about a teaspoon full and is worth about NZ$3,000.   


Pounamu
Known in English as greenstone, pounamu is found in similar deposits to alluvial gold, in the river systems of the West Coast region.

The stone encompasses nephrite and bowenite, but not jade. It is a tough mineral that takes on a shine when polished and is amenable to carving. 


Petajoule
A unit for measuring energy; a petajoule is the energy equivalent of about 163,452 barrels of oil.

Across all energy sources, New Zealand consumes about 600 petajoules (PJ) of energy each year.

 

Prospecting
Prospecting, as defined in the Crown Minerals Act, is a low-impact minerals activity to identify land likely to contain mineral deposits or occurrences, it includes: geological, geochemical, and geophysical surveying; aerial surveying; taking samples by hand or hand-held methods; taking small samples offshore via low-impact mechanical methods.


Prospecting permit
A minerals prospecting permit (MPP) under the Crown Minerals Act, provides for  the holder to undertake prospecting activities.

It does not confer land access, which must be obtained by agreement with the landowner, nor does it confer a resource consent or other regulatory approval. 


Quarry
A quarry is the term for an opencast mine from which rock and other aggregates, and other non-metallic or industrial minerals such as clay, zeolite, limestone etc, are recovered.


Quartz
A commonly occurring, variably coloured crystalline mineral composed of silicon dioxide, quartz is a host rock for gold, and veins of quartz can bear significant quantities of the precious metal.


Rare earth element(s)
This term captures elements of the periodic table from number 57 through to 71 (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium), as well as the lighter, related elements, scandium and yttrium.

Despite their name, the rare earth elements are not especially rare. The word “rare” originally denoted “strange”. Each REE is more common in the earth’s crust than silver, gold, or platinum. In fact cerium, yttrium, neodymium and lanthanum are more common than lead.

Rare earth elements are found in some minerals (known as rare earth minerals) including bastnäsite, monazite, allanite, xenotime, and loparite, and also in lateritic ion-adsorption clays (eg red soils in Australia).

Monazites are found on the West Coast and elsewhere in New Zealand, though to date have not been mined in commercial quantities.

Resource Management Act
The Resource Management Act is one of New Zealand’s chief pieces of environmental legislation and is one of many statutes governing mining, and managing the environmental impacts of mineral recovery.


Resource consent
Under the Resource Management Act, certain activities will require resource consent, which are in some instances influenced at central government level by a national policy statement (making policy consistent nationwide), and in some cases a national environmental standard. The decisionmaker on a resource consent application is a district and/or regional council, or unitary council, or the Environment Court, or a higher court. Applications for nationally significant projects can be subject to a ministerial “call-in”, to be heard by a Board of Inquiry.

Resource consents are required in most instances for activities relating to mining, with some variation in regulatory requirements across New Zealand.


Schist
A foliated and metamorphic rock, schist commonly derives from sandstone or mudstone, after the application of high temperatures and/or high pressures from burial under layers of rock and from tectonic processes, and millions of years of time for solid-state chemical process to occur. Often used in construction and landscaping for decorative purposes, schist is a popular and valuable rock.


Schedule 4
Schedule 4 of the Crown Minerals Act lists areas of public conservation land to which minerals access restrictions apply.

This includes:

  • Any national park (under the National Parks Act 1980)
  • Any reserve classified as a nature reserve (under the Reserves Act 1977)
  • Any reserve classified as a scientific reserve (under the Reserves Act 1977)
  • Any part of a reserve set apart as a wilderness area (under the Reserves Act 1977)
  • Any conservation area declared a wilderness area or a sanctuary area (under the Conservation Act 1987)
  • Any area declared a wildlife sanctuary (under the Wildlife Act 1953)
  • Any area declared a marine reserve (under the Marine Reserves Act 1971)
  • Any land within a wetland and notified to the Ramsar Secretariat by the minister responsible for the Ramsar Administrative Authority (under the Conservation Act 1987)
  • The area described in the Otahu Dedicated Area Notice 1976
  • The area described in the Parakawai Geological Area Notice 1980
  • All land held, managed, or administer under the Conservation Act situated n any island in the area bounded by latitude 35°50’S and latitude 37°10’S, and longitude 177°E and longitude 174°35’E, other than Red Mercury Island (Whakau), Atiu or Middle Island, Green Island, or Korapuki Island in the Mercury Islands Group.
  • All land held under the Conservation Act situated on the Coromandel Peninsula and lying north and northwest of State Highway 25A (Kopu-Hikuai Road) and on the road from Hikuai to Pauanui Beach known as the Hikuai Settlement Road.
  • The internal waters of the Coromandel Peninsula
  • The Kaikoura Island Scenic Reserve in Auckland City
  • Rakitu Island Scenic Reserve

In total, these areas cover about 40% of all conservation land in New Zealand, with miners only feasibly able to apply for access to mine in the remainder of the conservation estate.  


Spoil
This is the term used to describe rock or earth material removed from a tunnel or other workings of an underground mine during its establishment or operation. This spoil is often stockpiled and used to backfill any voids during and after mining operations.

Stewardship land
New Zealand’s public conservation land encompasses about one-third of New Zealand’s total land area. Of that, stewardship land comprises about a third (or around 10% of New Zealand’s total land area of 26.3 million hectares).

Stewardship land, like all conservation land, has a range of conservation values from low to high, and is administered and managed under the Conservation Act. The official term is “stewardship area”.

As with other public conservation land not listed under Schedule 4 of the Crown Minerals Act, miners can apply for access to mine on stewardship land at the discretion of the conservation minister, or departmental staff acting on his or her behalf, and in the case of significant projects, also the energy and resources minister.


Sub-bituminous coal
Coal of sub-bituminous rank tends to be burnt and used as a source of energy for heat or steam and is commonly referred to as “thermal” coal for this reason. Such coals produced on the West Coast are largely sold to domestic customers in the South Island, for use in food production and space heating.


Suction dredge
A suction dredge is a small-scale goldmining plant used by hobby goldminers to suck gravels and sands from small river and creek beds. Miners then process this material on tables that combine gravity and water to separate fine nuggets and flakes of gold from lighter sand and gravel, which is then returned to the water.

Suction dredges tend to be owned and operated by individuals searching for gold as a largely recreational or lifestyle pursuit.


Tailings
This is the term used to describe processed materials left over from ore or a feedstock after the physical or chemical separation from that ore of a desired mineral. This could be milled or crushed quartz from a hard-rock gold mine. and fine-grained waste materials from alluvial gold mining.

Tailings typically need to be safely stored in impoundments, to prevent the release or discharge of unwanted elements such as arsenic into the environment.


Underground mining
As opposed to opencast mining, which occurs at surface level, underground mining involves establishing tunnels and mine workings beneath the ground to discover and extract mineral resources such as gold-bearing quartz, or coal from seams.

While underground mining is less common in New Zealand and worldwide in modern times due to the prevalence of opencast mining, there are still many mineral resource deposits best accessed or only able to be accessed via underground methods, including on the West Coast and elsewhere in New Zealand.

West Coast
The region of New Zealand in the South Island and west of the southern alps, stretching from Awarua Point in the south to Kahurangi Point in the north, and comprising the Buller, Grey, and Westland Districts. Also known as Tai Poutini.


Westland
The southernmost and largest of the three districts of the West Coast, spanning from the Taramakau River in the north to Awarua Point in the south.


Wildlife Act 1953
Administered by the Department of Conservation, the Wildlife Act protects the majority of New Zealand’s native vertebrate species.

Exploration and mining operations, whether occurring on public conservation land, private land, or any other form of land tenure, must comply with the Wildlife Act. Requirements under authorisations will be determined by staff of the Department of Conservation. 


Zircon
Found in some placer or heavy mineral sand deposits on the West Coast in the same sands that bear ilmenite, garnets, monazites and the like, zircon hosts the metal zirconium.

Applications are wide ranging, including the nuclear power generation industry in cladding, fuel rods, for alloying with uranium, and for reactor-core structures, as well as an alloying agent in some magnesium alloys, and as an additive in the manufacture of certain steels.