The long haul: Reports focus on Idaho-Maryland Mine’s impact to roads, noise, property values
If the Idaho-Maryland Mine reopens, haul trucks will become a familiar sight on Grass Valley roadways for the next 20 years, according to project plans submitted by Rise Gold Corp. to Nevada County.
The trucks will make up to 100 trips a day, averaging 50, from 6 a.m. to 10 p.m., seven days a week.
They will be transporting engineered fill, or barren rock and sand tailings, generated from tunneling underground. The proposed plans designate two routes for the trucks: one route between the Brunswick and Centennial sites, along Brunswick Road and Whispering Pines Lane; and one route between the Brunswick site and Highway 20/49, along Brunswick Road, for engineered fill to be delivered to potential customers.
The Centennial site, where engineered fill will be used as part of a restoration project, is expected to take five years to complete, during which time the trucks will be divided between the two routes. For the next 15 years, the number of trucks on the road will not decrease, but will move entirely to the Highway 20/49 route.
For many, the trucks represent one of the key issues surrounding the reopening. MineWatch Nevada County has listed the trucks as one of its eight main reasons to oppose the mine.
“I think the trucks would be the most egregious, worst thing we’d notice right away,” said Elizabeth Martin, CEO of the Sierra Fund and former member of the Nevada County Board of Supervisors. Whether they’re the biggest concern, she said, depends on where someone lives. “If you use those roads all the time, it will be the only thing you’re upset about,” she said. “If you don’t use those roads as much, but your well has gone dry, well, that will be the thing.”
The evidence so far is mixed. Both traffic and road quality may become noticeably worse, according to noise and traffic reports conducted by external consultants and submitted by Rise Gold to the county for review. Research has also found that mining trucks decrease property values and require significant energy use.
Still, reports show that the trucks will not drastically increase the noise level of surrounding areas, and Rise Gold will have to pay fees to the county that go toward alleviating the traffic and road quality problems.
The proposed routes for the mining trucks include roadways and intersections used by employees who work along Loma Rica Drive, as well as Centennial Circle. The routes are adjacent to approximately 14 homes.
The traffic report submitted by Rise Gold and conducted by the consulting firm KD Anderson and Associates used probabilistic modeling to estimate the effects of the added trucks and mine employee traffic on these roadways and intersections. Quality of traffic is measured in Level of Service, receiving a grade from A to F.
Several of the intersections moved down a grade, sometimes two or three grades, after the project conditions were added. Some, which were already determined “unacceptable” at Level of Service F, had serious increases in delays.
For example, the northbound intersection at Idaho Maryland Road and Centennial Drive is rated F during afternoon peak hour (4 to 6 p.m.) conditions, with an average delay of 59.1 seconds. The report estimates that the delay will increase to 99.8 seconds if 11 construction projects currently approved by the county are also underway at that time. Adding the truck and employee traffic presented by the mine’s Centennial route, the delay increases to 148.4 seconds.
Similarly, the westbound intersection of Brunswick and Idaho Maryland roads, also rated F, has an average delay under morning peak hour (7 to 9 a.m.) conditions of 61.8 seconds. With the 11 projects, the delay increases to 97.9 seconds. Adding the traffic generated by the Highway 20/49 truck route, that delay increases to 201.7 seconds.
To reduce the effects of the trucks on traffic, the report proposes several changes, including adding signals to the affected intersections, like Brunswick and Idaho Maryland, in order to keep their Level of Service grades at acceptable levels.
Rise Gold intends to pay a development fee per square foot of construction to help fund the signals, according to Jarryd Gonzales, the director of PR and communications for Rise Grass Valley, the local subsidiary of Rise Gold Corp.
Wear and tear on the roads will also increase as a result of the trucks. According to a pavement quality analysis in the same report, “additional project truck traffic would result in a shorter life span of the pavement or increased maintenance.” The exact effects of truck traffic on pavement quality were not calculated, as the authors declared they were “beyond the scope” of the study.
Rise Gold will be required to enter into a “road management mitigation agreement” for Brunswick Road, said Gonzales. The details of the agreement will be specified in the upcoming draft Environmental Impact Report (EIR), compiled by a county consultant and based on Rise Gold’s submitted documents, peer reviews, and public comments.
The report is set to come out this summer or fall, though the exact date has yet to be determined, according to Matt Kelley, senior planner for Nevada County and the county’s project contact for the mine.
Right now, Rise Gold plans to pay about $257,000 in fees to cover their share of road improvement and traffic signalization, which include the Nevada County Local Traffic Mitigation Fee, the Regional Transportation Mitigation Fee, the Grass Valley Transportation Impact Fee, and a Caltrans fee, Gonzales said.
The noise generated by the trucks will be “less than significant,” according to a large-scale noise study conducted by Bollard Acoustical Consultants. Using inputs based on the maximum of 100 round trips per day, the consultants found some increases in decibel levels measured at the nearest residences to the truck routes, but determined they were below the threshold of significance.
“They are negligible,” Gonzales said. He also emphasized that the roads the trucks will occupy are already designated truck routes.
This does not mean that the trucks will be inaudible to those living or working nearby. As the report states, “audibility is not a test of significance according to CEQA (California Environmental Quality Act).” Some areas will see increases of up to 2.6 dB. For reference, a 3 dB increase is about the smallest change in volume that most people hear easily.
In addition to increased traffic and wear and tear, the trucks may cause a drop in nearby property values, though this was not assessed in the traffic or noise reports. A recent study found that rock mining operations significantly decrease property values within a 10-mile radius, due in part to increased truck traffic.
Such an effect could be a game changer for those who would otherwise support the reopening of the mine. “Even very conservative pro-business people don’t want their property values to be diminished,” Martin said.
The emissions produced by the trucks were also not calculated in the submitted reports. They will be assessed, however, as part of the air quality and greenhouse gas analysis of the upcoming EIR, said Kelley.
The environmental impact of haul trucks can be sizable. According to a 2019 study on mining and emissions, haul trucks make up 30% to 50% of their mines’ total energy use. Large mine haul trucks currently in use emit a combined 68 million tons of CO2 per year, about the total greenhouse gas emissions of Finland or New Zealand.
However, Rise Gold has opted to use Tier 4 diesel engine trucks “as part of a conscious decision to be a good steward of the Nevada County environment,” Gonzales said. These trucks are smaller and more expensive, but reduce emissions by 97% compared to Tier 3 diesel engine trucks.
Whether these effects are significant relative to the other potential consequences of the mine remains to be seen. The county doesn’t have an answer right now, though the EIR will likely prove illuminating.
“There’s not really a priority list or anything that the county is looking at specifically,” Kelley said. “They’re all evaluated independently as part of the EIR, they all have their own chapter, their own discussion.”
Martin thinks the concerns presented by the mine can be condensed into three main issues. First: dewatering, a risky process which she said caused nearby homes, businesses, and a local elementary school to lose water during the reopening of the nearby Siskon Mine in the 1990s, despite conclusions in the county’s EIR that the process would not affect water availability.
Second: the trucks, and the subsequent ramifications for traffic, road quality, and property values.
Third: the engineered fill itself, and what it’s composed of. It could be “safe” rock, but it could also contain arsenic, mercury, or other toxic materials. Research has shown that mercury levels remain heightened decades later in areas where gold mines once operated.
Gonzales contends that the new mine will not share the same dangers as previous ones. “I’ve been saying, ‘this is not your grandfather’s gold mine,’” he said. “This is a state-of-the-art mine.”
The mine will produce 94% less waste than the industry average, and use zero-emission equipment. But the hazards of dewatering, the release of toxic substances, and all the associated “unknowable unknowns,” as Martin calls them, remain.
For most people, the existence of the trucks may simply serve as a routine, above-ground reminder about what is going on underground.
“It will be impactful, there’s no question about it,” Martin said. “And it will be impactful every single day. It will be the face, it will be the smell, it will be the sounds.”
The Sierra Fund plans to provide expert testimony to the Board of Supervisors in upcoming meetings. After the EIR is released, the public will have an opportunity to comment before a final decision is reached.
Shira Moolten is a freelancer for The Union
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