Absolutely. As luck would have it, many epithermal mineral deposits have both sparkly hematite and copper ore in the same structure. This is a well-known motif in mineral exploration. They show up in the same geography but are separated into different layers. You can find many papers on the structure of these ore bodies. These are known as supergene deposits[0].
The most important features of these deposits is that they act like distillation columns for metals. Due to weathering and associated sulfuric acid, different metals separate out at different layers of the geology. This creates valuable concentrations for mining purposes.
In modern mining, we kind of ignore these structures for iron mining purposes even though they are frequently > 50% iron by mass. If you find such a thing, you are more interested in the gold, silver, copper potential that is capped by an iron-rich gossan mineral. Iron is a cost sensitive commodity, you need to be able to mine it at very high concentrations and scales to be profitable. If that mineral has a pile of gold, silver, etc distilled underneath it, you’ll be more interested in that.
Not all copper comes from these mineral formations but a lot is. Often, the hematite is mixed in with the copper mineral. I have a mineral exploration prospect right now which is essentially this. Amazing hematite crystals mixed with copper with strong assay signs of gold underneath. It is a predictable motif in mineral exploration.
This is similar to the "rare earth tailings" phenomenon, isn't it. A mine is built to extract one metal, the most profitable at that time, and everything else unextracted ends up in mine tailings or refinery slag. But, in addition to truly worthless silicates, that "waste" includes a bunch of other metals at low purity which may eventually be economic to extract.
"Amazing hematite crystals mixed with copper with strong assay signs of gold underneath."
Did you actually assay out anomalous gold concentrations or are you seeing the sulfides and oxides that are associated with gold? If the former, what sort of concentration are you getting?
I have only assayed samples from the iron cap. You would not expect to find much in that part of the formation but it still came in at 1-2g/ton. There is a large area of visually striking bornite[0] that I have not yet been able to properly sample which is roughly the area you would expect the gold to concentrate. It is in the walls of a narrow, deep canyon at high elevation. The region was mined for gold/copper a century ago, so the existence is not surprising.
The location makes access extremely challenging. It requires 3 hours of hiking, assuming you are fit, and borderline technical mountaineering once you get close to the site. The lower parts of the canyon are also under tens of meters of ice most of the year, which creates a separate set of safety issues. When these mountains were prospected in the 1920s, it would have been underneath a deep permanent snow field. I've visited some of the old gold mines in the area for calibration and this deposit appears substantially larger than those.
The discovery was accidental. I was looking for a waterfall I had seen on satellite imagery in the backcountry and came across an enormous chunk of molybdenite[1] while climbing across granite scree. I made several trips to find the source of the molybdenite higher up the mountains, which I never did, but while searching for that I localized a bunch of other beautiful sulfide/oxide mineral specimens to the above canyon. It gives me a great excuse to explore parts of the mountains no one has been into before.
Honesty I know a bunch of people who are burntout climbers and burntout geologists - sounds like a blast. Fun mineralogy with climbing that’s not…super exotic but still fun? I’d pay for it.
Some of those climbs are dangerous though. The Chambless Skarn has a vertical wall of solid epidote you have to scale to reach a massive pocket of world-class hedenbergite, at the top of the mountain. That wall is a few stories tall, and your only grip is the side walls of the rock around you.
The most important features of these deposits is that they act like distillation columns for metals. Due to weathering and associated sulfuric acid, different metals separate out at different layers of the geology. This creates valuable concentrations for mining purposes.
In modern mining, we kind of ignore these structures for iron mining purposes even though they are frequently > 50% iron by mass. If you find such a thing, you are more interested in the gold, silver, copper potential that is capped by an iron-rich gossan mineral. Iron is a cost sensitive commodity, you need to be able to mine it at very high concentrations and scales to be profitable. If that mineral has a pile of gold, silver, etc distilled underneath it, you’ll be more interested in that.
Not all copper comes from these mineral formations but a lot is. Often, the hematite is mixed in with the copper mineral. I have a mineral exploration prospect right now which is essentially this. Amazing hematite crystals mixed with copper with strong assay signs of gold underneath. It is a predictable motif in mineral exploration.
[0] https://en.wikipedia.org/wiki/Supergene_(geology)