The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Rich deposits of heavy critical mineral found with SE, NW zinc North of 60 Mining News – September 1, 2018
Constantine Metal Vice President of Exploration Darwin Green examines an outcrop of barite-sulfide boulders rich in zinc and copper at Mount Henry Clay, one of numerous VMS prospects found across the Palmer project in Southeast Alaska.
Located about 35 miles north of Noatak, the barite rich mineralization in the Red Dog District is near the southwest corner of the National Petroleum Reserve – Alaska.
While not the flashiest of the 35 minerals on the United States Geological Survey's critical list, barite plays an essential role in America's energy sector.
Barite got its name from the Ancient Greek word for heavy, barús, and it is the high specific gravity that earned this mineral its name that makes it a critical mineral.
Added to drill mud, a solution that serves multiple purposes in bore drilling, barite's weight helps maintain the integrity of the drill hole and prevents oil and natural gas wells from blowing out when reservoirs are tapped. Examples of what happens when these pressured basins are drilled into without barite can be seen in historical photographs showing geysers of oil spewing from new wells drilled in the early 20th Century.
"More than 90 percent of the barite sold in the United States was used as a weighting agent in fluids used in the drilling of oil and natural gas wells," USGS penned in its annual report, Mineral Commodity Summaries 2018.
Barite also lends its weight to heavy cement used as a jacket around underwater pipelines that transport oil and gas from offshore production, adding an extra layer of protection and prevents the pipes from floating.
While the U.S. Geological Survey withheld information on domestic barite production in 2017, it is estimated that more than 75 percent of the roughly 3 million metric tons of barite used in the United States last year was imported.
Constantine Metal Resources Ltd. would like to shift this balance by producing a high-quality barite at Palmer, an advanced staged exploration project in Southeast Alaska that is better known for the zinc, copper, silver and gold also found there.
China weighs heavy
China, which currently produces more than half of the world's supply of barite, was the largest supplier of this critical mineral to the United States. The balance was supplied from India, Mexico and Morocco.
"Global dependence on a limited number of countries for specific mineral commodities could lead to sudden supply disruptions for the United States, and barite is one such commodity," USGS penned in a 2014 report on barite.
While America's petroleum industry would be hit hardest by such a supply disruption, barite also is used in products such as paints, plastics, rubber and even playing cards.
Taking advantage of the high specific gravity that makes barite ideal for drilling mud, some card makers mix this mineral in the paper they use. This makes the cards heavier and therefore easier to deal around the table.
The mineral also lends its weight to mudflaps, which helps to keep them from "sailing" when the trucks and other vehicles they are mounted to are traveling down the highway.
Other uses of barite by the auto industry is in brake and clutch pads, and as a metal protectant in paint primer.
While most of barite's industrial uses take advantage of its weight, its ability to significantly blocks x-ray and gamma-ray emissions adds another layer of uses for this critical mineral.
Taking advantage of this radiation blocking characteristic, is used as aggregate in high-density concrete for shielding around x-ray units in hospitals, nuclear powerplants, and university nuclear research facilities.
This ability to block x-ray emissions is also used as a medical diagnostic tool.
When a patient drinks a thick liquid containing ultrapure barite, barium, the barite coated digestive tract shows up on x-ray. This provides physicians with the ability to "see" soft tissues that otherwise would not show up on this type of imaging.
Quality barite in SE Alaska
Like many of the other minerals critical to the United States, barite was previously mined in Alaska. This production came from Castle Island near the town of Petersburg on the Southeast Panhandle.
Three companies – Alaska Barite Co., Inlet Oil and Chromalloy America – produced roughly 750,000 metric tons of barite from Castle Island from 1966 to 1980.
While very little reserves of barite are known to remain on Castle Island, a deposit with some 2 million metric tons of this critical mineral has been outlined so far at the Palmer project further north on the Southeast Alaska Panhandle.
Being advanced by a joint venture between Constantine Metal Resources (51 percent) and Dowa Metals & Mining Co. Ltd. (49 percent), the Palmer project is better known for the base and precious metals also found there.
According to a resource calculated in 2015, the South Wall-RW deposit at Palmer hosts 8.1 million metric tons of inferred resource averaging 5.25 percent (940.4 million pounds) zinc, 1.41 percent (252.6 million lb) copper, 0.32 g/t (83,600 ounces) gold and 31.7 g/t (8.3 million oz) silver.
This resource area is made up of roughly 22 to 25 percent barite by weight.
"Barite constitutes about a quarter of the rock mass of the defined mineralized zones and ... has the potential to materially enhance the value of the already high-value mineralization," said Constantine President and CEO Garfield MacVeigh.
Wanting to find out whether the barite could be economically recovered in a product that would be useful to the oil and gas sector, Constantine initiated a metallurgical program focused on Palmer's barite earlier this year.
This work demonstrates that 91.1 percent of the barite at Palmer can be recovered in a clean high-grade concentrate with a specific gravity of 4.44.
The specific gravity is important for barite that would be used as a weighting agent in drill mud.
American Petroleum Institute, a trade association that establishes and maintains standards for the global oil and gas sector, prefers a 4.2 specific gravity for barite used in oil and gas drilling. Due to few deposits in the United States able to produce this heavy a barite, API lowered this minimum specific gravity requirement for barite to 4.1 in 2010.
Contaminants in barite can cause problems while drilling, especially abrasive particles that can ruin bits.
In addition to a specific gravity well above requirements, Constantine reports that the testing shows that a barite concentrate from Palmer meets all API and U.S. Environmental Protection Agency specifications for oilfield drilling grade barite, including particle size and purity, and appears to be a market-ready product.
"These results confirm that a premium-quality barite concentrate can be produced from the copper-zinc ores at Palmer, and that it can be achieved by the addition of simple steps to mineral processing," said Constantine Metal Resources President and CEO Garfield MacVeigh.
Barite market analysis
With the metallurgical results showing quality barite can be recovered from Palmer, Constantine has commissioned experts in the market to assess wholesale barite prices for different North American oil basin markets.
Preliminary estimates range from US$170 per short ton to US$225 per short ton.
The market analysis will also include an analysis of transportation options and cost to access the most likely of these markets.
Palmer's proximity to the Pacific Rim deep-water port at Haines, is expected to have a significant competitive advantage to delivering barite in North America.
"The project's excellent location, 60 kilometers (37 miles) by road from deep tidewater facilities enables low-cost shipping to markets," MacVeigh said in February.
Alaska, with its oil and gas fields on the North Slope and in Cook Inlet, would be a good market for Palmer barite.
On top of its locational advantage, the barite at Palmer would also benefit from being produced as a co-product of the copper, zinc, lead and precious metals also found there.
Much of the roughly 2 million metric tons of barite in the current resource would be mined with the ore at a future Palmer Mine and then need to be stored as either waste rock or tailings. By adding the extra step of producing a saleable barite product, Constantine and Dowa could get paid for this critical mineral that is already being handled.
"This may have very positive implications with the potential to both enrich gross metal value per tonne (metric ton) and provide significant environmental and operational benefits by reducing waste," said MacVeigh.
Adding barite plus metals
The amount of barite, along with the suite of base and precious metals, contained in the resource at Palmer is expected to swell in the coming months.
Over the three years since a resource was last calculated for the South Wall-RW, which currently hosts the resource at Palmer, drilling has encountered significant expansion areas of this deposit.
The 2017 drill program also discovered AG Zone, an emerging deposit about 3,000 meters south of the resource that seems to be particularly rich in barite.
The discovery hole at AG cut 9.2 meters of massive barite-sulfide averaging 312 g/t silver and 0.9 g/t gold.
This year, Constantine and Dowa budgeted US$9 million for expanding these known deposits and to discover new zones of barite, copper, zinc, lead and gold.
CMR18-114, drilled this year, cut 21.3 meters grading 0.5 g/t gold, 92 g/t silver, 1 percent zinc, 0.4 percent lead and 55 percent barite.
"AG Zone was discovered in 2017 and is rapidly revealing itself to be a significant new precious-metal rich massive barite-sulfide deposit with excellent size potential," said MacVeigh.
Following this year's drill program, Constantine and Dowa plan to commission a new resource for Palmer that will likely be the first to include a definitive calculation of the resource found there.
In addition to South Wall-RW, this updated calculation is expected to include a maiden resource for the barite-rich AG Zone.
The upgraded resource, along with the new metallurgical understanding of the deposits, will form the basis of a preliminary economic assessment for Palmer, providing the first look at the viability of developing a mine at this barite-rich VMS project near the coastal community of Haines.
Barite-rich Red Dog district
While Palmer is the most advanced, and likely most economically viable source of barite in Alaska, there are other metal-rich deposits in the state that host intriguing quantities of this critical drill mud mineral.
In fact, the Red Dog district in Northwest Alaska, best known for its fantastically high-grade deposits of zinc, is believed to host well above 1 billion metric tons of barite.
Teck Resources Ltd. produced roughly 1.19 billion pounds and 254.4 million lb of lead at Red Dog last year from high-grade deposits on lands owned by NANA Region Corporation Inc.
While the deposits currently being mined contain some barite, the mass quantities of this critical mineral are associated with the next generation of Red Dog deposits about five miles to the north.
Anarraaq consists of a barite body, estimated to be as much as 1 billion metric tons, and an 18 metric ton zone of massive sulfide with 19.4 million metric tons of inferred resource averaging 14.42 percent zinc and 4.2 percent lead.
The much bigger deposit in this barite-rich area, however, is Aktigiruq. While an NI 43-101-compliant resource estimate has yet to be reported for this deposit, the widely spaced holes drilled prior to 2017 suggest this exploration target has somewhere between 80 million and 150 million metric tons of material averaging around 13 percent zinc and 4 percent lead.
Though the seasonality of the Arctic port that currently delivers zinc and lead concentrates from Red Dog would currently restrict shipments of barite from the district, this regions proximity to the west end of Alaska's oil-rich North Slope provides interesting market potential for the massive deposits of barite found in this minerals-rich corner of Northwest Alaska.
In fact, the southwest corner of the National Petroleum Reserve-Alaska, a 23.6-million-acre oil-rich region of the North Slope is only about 30 miles northeast of Red Dog.
Late in 2017, the USGS estimated that NPRA, along with adjacent state and Tribal lands and waters, hosts roughly 8.7 billion barrels of oil and 25 trillion cubic feet of natural gas.
Exploration and development of this massive domestic energy resource would require a lot of barite, a critical mineral that could be supplied by Palmer, Red Dog or imported from overseas sources.
Editor's Note: "Critical Minerals Alaska – Barite" is the eighth of a series of articles being published in North of 60 Mining News that investigates Alaska's potential as a domestic source of minerals deemed critical to the United States. At least 29 of the 35 critical minerals and metals identified by the U.S. Geological Survey – antimony, arsenic, barite, beryllium, bismuth, chromium, cobalt, fluorspar, gallium, germanium, graphite, hafnium, indium, magnesium, manganese, niobium, platinum group metals, rare earth elements, rhenium, rubidium, scandium, tantalum, tellurium, tin, titanium, tungsten, uranium, vanadium and zirconium – are found in Alaska.
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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