McIntyre Creek

Pueblo Memorial: 60.7222°, -135.1747°

Copper King claim: 60.73917°, -135.1453°

Grus roadcuts: 60.73389°, -135.1478°

McIntyre Overlook: 60.73389°, -135.1494°

The McIntyre Creek drainage hosts four locations of geologic interest, all accessed by the Fish Lake Road. This tour highlights the discovery of mineralization in the Copper Belt, plus its early underground mining history. In addition, it explores the role glacial and fluvial processes played in exposing copper mineralization and enabling discoveries by early prospectors.

Along the Fish Lake Road, McIntyre Creek has steep banks and a narrow creek bed. These distinctive features are characteristic of a glacial meltwater channel developed in bedrock. Upstream, the valley cross-sectional shape is wider and shallower because the stream eroded less resistant glacial sediments.

This meltwater channel was a key factor in discovering copper mineralization, and it formed at the end of the last ice age. Meltwater flowed off the side of valley glaciers carving channels roughly oriented parallel to the main valley direction, which was still filled with ice. The meltwater carved through or eroded glacial sediments and bedrock, exposing some of the copper occurrences. The Copper King, Pueblo, Empress of India, and Big Chief showings are all located in or adjacent to meltwater channels.

Prospectors on their way to the Klondike discovered copper near Whitehorse in 1897, but the first claim was not staked until 1898. By 1899 most of the presently-known deposits were found. The first claim was staked by Jack McIntyre along what is now known as McIntyre Creek - the claim, and the future underground mine, were called Copper King.

At the start of the Fish Lake Road, cliffs of light-coloured rock look remarkably crumbly and delicate. This is a rock texture known as grus, which is a term to describe granitic rocks that have experienced significant weathering by interaction with hydrothermal fluids.

During formation of grus, the igneous mineral biotite (a black mica) is altered to the clay mineral vermiculite, which has ability to expand and contract with varying water content. These volumetric changes help fracture the rock and decrease its cohesion. Other mineralogical changes include the formation of new secondary iron oxide minerals, and weathering of plagioclase feldspar to the clay minerals illite and kaolinite. Learn more about grus below!

The Pueblo mine was the largest producing underground mine during the early phase of mining in the Whitehorse Copper Belt, with production between 1912 and 1920. In total, it produced 126,000 tones of high-grade copper ore with an average grade of 3.5% copper. After Pueblo mine shut down, there was a hiatus of 47 years until mining recommenced in the Copper Belt, with open-pit mining at the Little Chief deposit in 1967. The mineralization at Pueblo is unique in the Copper Belt because the main iron-oxide mineral is specular hematite (Fe ₂ O ₃ ), instead of the magnetite (Fe ₃ O ₄ ) which is found elsewhere. The only copper sulfide mineral is chalcopyrite - no bornite is present. Check out the  Whitehorse Copper Belt main page  for more information on specific minerals found in the Copper Belt.

On March 21, 1917, a cave-in at Pueblo trapped nine men in the underground workings. A underground mine rescue team pushed forward a drift through solid granite into the collapsed area and rescued three miners from the 300-foot level. The 85 foot-long drift (horizontal excavation) was excavated in 72 hours, believed to be a speed record at the time. On March 29, eight days after recovery efforts commenced, the mine manager abandoned the effort due to concerns about the imminent danger of a cave-in taking place in the main shaft. The remaining six miners were never found. An investigation determined that the high inflows of water into the mine (500-600 gallons per minute) had led to the decreased structural integrity of the underground workings at the 200- to 400-foot levels.

The Pueblo mine disaster was the trigger for the establishment of worker's compensation legislation in the territory. Shortly after the disaster, the Workmen's Compensation Ordinance received assent in the territorial legislature.

In 2000, a plaque marking the tragic event was put in place by local miners. Little of the Pueblo mine's surface footprint still exists, as the Icy Waters fish farm is located on the site.

Now that you have learned about the McIntyre Creek drainage, jump into the immersive virtual field trip to further explore the landscape and look at some outcrops!