North of 60 Mining News - The mining newspaper for Alaska and Canada's North

North Arrow Minerals Inc. May 13 announced it has begun the engineering and cost analysis for a small-scale mobile diamond recovery plant to process bulk samples from its Naujaat project about nine kilometers (5.6 miles) from the coastal community of Naujaat, Nunavut.

The property hosts at least eight kimberlite pipes. Q1-4 kimberlite is the largest and richest of the kimberlites discovered so and has been the focus of North Arrow's work since acquiring Naujaat (then known as Qilalugaq) from Stornoway Diamond Corp. in 2013.

According to a calculation completed in 2013, the top 205 meters of the Q1-4 kimberlite hosts 48.8 million metric tons of inferred resource averaging 53.6 carats per hundred metric ton, or 26.1 million carats

Based on limited exploration, it is estimated that another 7.9 to 9.3 million carats of diamonds are between 205 and 305 meters of the Q1-4 kimberlite.

North Arrow is currently planning for collection of a 10,000 metric ton bulk sample from the Q1-4 deposit and, as part of this work, has initiated an engineering design and costing study of a small-scale mobile diamond recovery plant.

The purpose of the bulk sample will be to evaluate diamond size distribution and value characteristics, with emphasis on a distinct population of high-value, fancy, yellow to orangey-yellow diamonds that have been identified in the deposit.

North Arrow has engaged Imilingo Mineral Processing of Pretoria, South Africa, TOMRA, and Microlithics Laboratories of Thunder Bay, Ontario to investigate modular diamond recovery design options incorporating TOMRA's X-ray transmission (XRT) sorting technology with a view to recovering diamonds greater than 3 millimeters (at least half a carat) in size.

"Over the last number of years, TOMRA's XRT sorting technology has changed the diamond mining landscape by providing an X-ray transmission sorting solution that improves diamond recoveries while reducing breakage and water use compared to more traditional diamond recovery circuits," said North Arrow Minerals President and CEO Ken Armstrong. "We believe XRT sorting technology can also be used for the evaluation of diamond deposits and is an ideal recovery solution for the Q1-4 diamond population."

The focus on recovery of diamonds greater than 3 mm is an important component of the study announced today. A significant amount of the cost associated with processing past Q1-4 kimberlite samples has been related to ensuring and documenting the recovery of diamonds down to 1 mm in size.

"While information on the 1 mm to 3 mm diamonds is important, most often the value of these diamonds does not impact the potential viability of the deposit being tested," said Armstrong. "This is certainly the case for Q1-4 where the value and size distribution of the fancy colored diamond population will be critical in determining the economic potential of the deposit."

North Arrow Minerals Inc.

These bags filled with material from the 2017 bulk sampling of the Q1-4 kimberlite are staged for sea transport to a facility for processing. North Arrow would like to build a diamond recovery plant to process bulk samples at the Naujaat project.

Q1-4's proximity to marine transportation infrastructure and a proposed new access route from the community of Naujaat improves the viability of setting up a bulk sample diamond recovery plant at the project.

Earlier this year, North Arrow reported that the community of Naujaat has submitted a project description for construction of an access trail that will pass roughly 1,500 meters southeast of Q1-4. The access trail will lie entirely within the Municipality of Naujaat and the hamlet has taken the lead as proponent for its design and construction and is pursuing financing options which are currently well advanced.

"Locating a small-scale diamond recovery plant at or near the project site will also reduce costs, improve logistics and increase local employment and business opportunities for the residents of Naujaat," Armstrong said.

Completion of the access trail is scheduled for summer 2020, which aligns with projected timing for delivery of a diamond recovery plant in support of a 10,000 metric ton bulk sample from Q1-4.

–SHANE LASLEY