Chuck Semborski reported to the Emery County Public Lands Council on the Deer Creek Mine closure. Deer Creek Mine ceased mining coal more than a year ago, but the actual closure of the mine is taking much longer reported Semborski. He said the longwall in the mine was relocated to the Bridger mine.
Deer Creek mine began monitoring the surface water as well as water in the mine in 1979. The presence of pyrite in the water is having an effect on how the mine is closed.
It’s a similar situation to what was found in the Crandall Canyon Mine. That mine was closed in August of 2007 and it started producing water in 2008.
The water in the Deer Creek mine is rich in pyrite. When the pyrite rich water hits the air, the pyrite materials solidify creating a murky/iron colored water. At Crandall this murky water has been undergoing a settling/holding process until it meets water discharge specifications.
Semborski said this occurs a lot in the east due to acidic conditions. This isn’t a problem in southeastern Utah usually.
Knowing what happened at the Crandall Canyon mine has helped the Deer Creek closure. Mine officials sampled a sealed area of the Deer Creek mine to see what the trend would be. They knew upon closure of the Deer Creek mine they would have trouble with water coming from the Rilda Portal as it is the lowest portion of the mine underworkings. The extent of the underground operations at Deer Creek would engulf the entire Salt Lake valley in scope. It’s a very large complex. All infrastructure for the mine was at the Deer Creek portal other than the breakout at the Rilda portal.
Knowing that the Rilda Canyon portal was the lowest point, the mine built water containment structures. They were widely spaced throughout the mine. The pyrite situation is unique to the company, they didn’t deal with it during the mine closure at Cottonwood.
At the time of the permitting for the Rilda portal, they didn’t know the mine would be closed a few years later. In 2013, the mine drilled long vertical holes from the surface. They installed bulkheads and piezometers.
The mine submitted their application for closure to MSHA. The Price District nine field office submitted the plan to Denver for their approval or they could ask for additional review. The Denver office sent the closure plan to Pittsburgh for a verification process and technical review. Semborski said he and other mine officials flew back to Pittsburgh to go over the plan with them. MSHA said they would approve the plan with a few revisions in safety factors. It was at that time the Gold King mine in Colorado flooded and MSHA denied the mine closure plan for Deer Creek.
Deer Creek was going to use aerated concrete for the bulk head structures which has no shrinkage and expands to fill an area. MSHA disagreed with this because it’s a new product without a proven track record.
So Deer Creek was going to switch concrete for the bulkhead structures. MSHA was concerned the bulkheads might not hold and flooding could occur. Semborski said only a portion of the water would be against the bulkhead and the bulkheads were designed for maximum pressure. The mine did a hydro test and pumped in grout. Then MSHA fully aware that Deer Creek was doing work issued Deer Creek a violation for working on it.
Deer Creek was taking measures to avoid a non-compliant discharge of water from the mine. The bulkheads were designed to divert the water so it would discharge down the Deer Creek side. The mine has a water discharge permit for the Deer Creek side, not Rilda. Rilda portal is located within the forest. You can’t have a water discharge on the forest any longer due to regulation changes.
Semborski said the water naturally wants to go to the Rilda side. While mining was occurring at Deer Creek all water was pumped and discharged from the Deer Creek side. They wanted to put a diversion in the mine so the gravity flow of the water would be out the Deer Creek side. The mine wanted to go out to bid to pump concrete into the mine, the concrete is $400 a cubic yard.
This concrete flattens out to 24 inches in two minutes and flows and fills an area. There have been many advances in concrete in recent years. The mine has spent $60 million to close the mine since Dec. 2014. They worked to remove all metal from the mine, all beltlines, coal chutes, everything possible. No other coal mine they know of has done this much work removing all equipment and any metal from the mine. Tons of steel was removed. There is only a small area of the mine which is still being ventilated now and a skeleton crew is still on duty at the mine until this final closure can take place.
MSHA issued a denial of the closure plan on Labor Day 2015. MSHA said they were hiring a technical company to review the mine closure plan.
The mile long drill hole was successful to take the water to the Deer Creek side where they could deal with the iron in the water. Any concerns with the pipeline in the mine would be entirely environmental as no one was in the mine so it wasn’t a safety or health issue. Then on Dec. 1, MSHA sent a three sentence decision to Deer Creek that said, They didn’t have jurisdiction to approve the project proposed. (pipeline within the mine)
Then Semborski said they met with the Division of Oil, Gas and Mining and told them they would have to submit the proposal to them which included five inches worth of documents. DOGM said they aren’t experts on this and they have had to hire a third party to analyze the mine closure plan. The mine got back a response in April that said they have concerns, but they feel they can be addressed. The hydrologist called and said they monitor water from working mines, not a closed mine. MSHA won’t allow any water to be retained in the mine at all so they denied the plan.
Semborski said there are not a lot of options for them. The water will flow to Rilda. Now the plan is to install a six mile pipeline from the Rilda portal, down Rilda Canyon to SR-31 and down the canyon to the diversion dam for the Huntington power plant. The mine has been in contact with all shareholders in that area North Emery Water Users, Castle Valley Special Service District and others to keep them informed of what’s being proposed now and to ask for their input.
The pipeline will be buried. It will go down the opposite side of the Rilda road than the culinary water lines. Semborski said they are very sensitive to the needs of the springs, they have helped with a slow-sand plant for North Emery water users in the past. Culinary lines must be 10 feet apart from non-culinary lines. They will also be sensitive of phone lines and an XTO gas line.
This plan to discharge the water at the diversion dam will require a change application. The mine has met with the Dept. of Environmental Quality and they said no discharge permit is required if the water is used in the power plant.
When the discharge water first came out of Crandall Canyon the pyritic iron was four or five parts per million now it is down to 1.2 parts per million. It’s been flushing through, and reducing over time.
The contaminated water from Rilda portal could continue for eight-12 years or longer. In talking to DEQ, they said the discharge could continue even after the power plant closes.
The mine has met with the BLM and the forest service. The BLM said NEPA would not need to be done and the project could receive a categorical exclusion if they stay within the utility corridor.
The pipeline project will cross the forest in three small segments. The forest service regulations state their categorical exclusion language requires a project must disturb less than five contiguous acres. The area involved in the pipeline is less than that, but not contiguous. Right now the forest service is leaning towards a small environmental assessment that must be completed.
The mine can’t just do nothing the water will come out of Rilda portal. Each month it’s costing the mine $.5 million to ventilate. A 17 people crew is still employed at the mine. They do a preshift and ventilate the mine. The mine is just sitting there, ready to close. Semborski said he expressed his disappointment the pipeline project would have to go through an EA,
He said the entire closure operation has been frustrating, but they have to go through it. Semborski said they have a set of plans for the waterline project and anyone interested can take a look at them.
Difficulties in final closure of Deer Creek
"Deer Creek mine wants to avoid the problems with discharge water that Crandall Canyon had to deal with. This picture is the sediment pond at Crandall Canyon."