SUCTION DREDGING IN THE
NATIONAL FORESTS
The following is the text from a new brochure published by
the USDA Forest Service, which was designed to help dredgers dredge responsibly. Please
check to see if this is available from your local Forest Service office. It is called
"Program Aid 1600, dated September, 1997." These should be distributed
throughout local clubs. In the event that it is not available to you, you can print and
copy this news release, and distribute copies to see that the word is passed to as many
dredgers as possible. Thank you.
SUCTION DREDGING IN THE NATIONAL FORESTS - Dredging Responsibly to Protect River
Ecosystems by United States Department of Agriculture - Forest Service in cooperation
with: Eastern Oregon Mining Association, Inc. (Baker City, Oregon), Eastern
Oregon Miners and Prospectors, Inc. (Baker City, Oregon), Idaho Gold Prospectors
Association (Boise, Idaho), Miners Alliance (Seiad Valley, California), Modern Gold Miners
& Treasure Hunters Association (Happy Camp, California), The New 49ers
Prospecting Organization (Happy Camp, California), Northwest Mining Association (Spokane,
Washington), Oregon Independent Miners (Veneta, Oregon), Public Lands for the People, Inc.
(Azusa, California), Public Lands Action Committee (Azusa, California), Shasta Miners and
Prospectors Association (Redding, California), Washington Prospectors Mining Association
(Seattle, Washington), Western Mining Council (Redding, California)
Welcome to Your National Forests!
For millennia the allure of gold has kindled the adventurous spirit of miners,
and many have sought their fortunes in its pursuit. In California alone, thousands of
49ers arrived from all corners of the world after James Marshall found gold in a
Sierra stream. Few people know that the California gold rush infused hundreds of millions
of dollars in the national economy and fueled the eastern economic engines that settled
the West. Over the past two centuries, miners have extracted gold from mountains and
streams throughout the United States, changing the course of the Nations future.
Today there is a new-found interest in gold mining. For individuals or small
groups of miners, only a few methods of gold mining are economically feasible. One of
these methods, a type of placer mining called suction dredging, removes gold from where it
has lodged in the beds of running creeks and streams. This method is increasing in
popularity in the national forests. This brochure is intended to increase readers
understanding of suction dredging; it is not intended to replace existing laws and
regulations.
Mining today differs from that of yesteryear: which sharing many of the traditions of
their forebears, todays miners must be aware of how their activities affect the
streams and surrounding ecosystems, and of the need to understand and operate according to
laws and regulations. These laws and regulations ensure continued use of national forests
and protect resources such as clean water and fish populations. Indeed, all users of
national forests must share in the stewardship as well as reap their benefits.
Please work with the US Department of Agriculture (USDA) Forest Service to make sure that
suction dredging is done in a manner consistent with current law and good natural resource
management, in order to maintain our forest resources for future generations. Enjoy using
your national forestsand good luck in your search for gold!
SHARED STEWARDSHIP
Though not as numerous as in the past, todays independent prospectors and
miners are still walking our national forests, searching for the mother lode. They
continue to be the on-the-ground eyes and ears of the mining industry. Their exploration
plays a large role in the development of the mineral industry.
National Forest System lands are experiencing an ever-increasing demand from a growing and
increasingly diverse population. There is demand for products, recreation, water,
wildlife, and fish, and for an almost endless list of intangible, but desirable, goals.
It is the policy of the Federal Government to foster and encourage the orderly exploration
and development of minerals to help assure our Nations industrial, economic, and
environmental needs. At the same time, the multiple-use doctrine recognizes the need to
maintain our national forests for current and long-term benefits to people, while a host
of other laws and regulations require that these multiple uses do not disrupt the natural
ecosystem. It is every citizens responsibility to help forge a way for these values
and objectives to co-exist.
The challenge for todays gold dredger is to demonstrate a
model of compatibility with other forest users, and sensitivity to the environment we all
share. Like all users of the national forests, gold dredgers must practice responsibility
and stewardship for our lands and streams.
Suction dredgers must recognize that the laws and regulations governing their activity
vary from place to place. Please refer to the back pocket of this brochure for local
information.
PLACER GOLD
Most gold originates in hard rock deposits, often within quartz veins. Through
weathering, such as cycles of freezing and thawing, and erosion, such as that caused by
flowing water, gold is separated from the rock. The gold flakes and nuggets released are
transported downslope by gravity and running water, and are eventually deposited in
streams.
Since gold is denser than the other streambed sediments, it tends to move downward to the
contact between the gravels and the underlying bedrock, collecting at the bedrock surface
and in the overlying few feet of gravels. During floods, when rushing waters transport
gravels rapidly downstream, the gold moves more slowly, often lodging in cracks, crevices,
and small holes in the bedrock surface.
Gold settles out where flowing water decreases in velocityfor example, at places
where the stream gradient decreases, downstream of large boulders, or where the bed
deepens into pools.
SUCTION DREDGING
Suction dredges are used within streams and rivers to remove the gravels
overlying bedrock and to access gold. The gravels are deposited into a sluice box, a long
container divided into sections by a series of slats called riffles. As water runs through
the sluice box, heavy particles, including gold, are concentrated behind the riffles, and
cleaned gravels exit from the final compartment to form tailings.
Dredges use high-pressure water pumps driven by gasoline-powered
engines. The pump creates suction in a flexible intake pipe 2 to 12 inches in diameter.
Suction dredges vacuum the streambed (which is composed of rock, gravel, and finer
sediment) with water through the hose into the sluice box. Both the pump and the sluice
box are usually mounted on a floating platform. Dredges are often positioned over the work
area by securing the dredge to trees or rocks with ropes or cables.
Suction dredgers often use hookah (air supply) gear in order to
dredge well below the surface of the water. The portion of stream bottom dredged ranges
from a few small excavations to the entire wetted area in a section of the stream. Larger
suction dredges have the capacity to excavate as much as several cubic yards of gravel
from the river bottom, depending on the type of streambed material and the skill of the
operator.
SUCTION DREDGING AND FISH
The health of fisheries is significant for several reasons. First, fisheries are
a major source of food and income, contributing hundreds of millions of dollars to coastal
economies, and constituting an essential source of income for many communities. For many
Pacific Coast Native American tribes, salmon are an integral part of their culture.
Recovery and protection of fisheries is an important goal for ecosystem managers on both
the Atlantic and Pacific coasts.
Second, each fish species, and in many cases each population or
stock of a species, has been honed by nature for survival within a specific environment.
Genetic differentiation among fish species may allow us to produce unique compounds that
could prove useful in the future, for example, in industry or medicine.
Of special concern to forestry managers are endangered and threatened species, and fish
caught either commercially or for recreation. Many species of salmonid fishes fall into
both of these categories.
SALMONIDS-UPRIVER MIGRATION
Salmonid fishes, for example, salmon, trout, and char, are considered one of
natures most intriguing mysteries. Many of them, including most species of salmon,
and some populations or stocks of steelhead, migrate form the stream where they
hatchedtheir natal streamto the ocean, where they spend as much as 80 percent
of their life. Then, after years spent swimming in the ocean, these salmonids are able to
find their way back to their natal waters to spawn. How they navigate their return to
these exact locations is still incompletely understood.
The term used to describe this type of migration is
anadromous (uh na druh mus), derived from the Greek for up
running. On the Pacific Coast, anadromous salmonids occur from southern California
north to Alaska and the Arctic Ocean; on the Atlantic Coast, from Connecticut to northern
Newfoundland.
Most salmonids begin migrating upstream between April and October. Since spawning may not
occur until fall, fish arriving in spring and summer stay in the river, staying cool in
deep holes in the river bed, and often taking cover under large woody debris and
overhanging rocks.
Spawning usually occurs where sediment-free, coarse gravels are
within a few feet of the water surface, often on shallow gravel bars. Female salmon
deposit eggs in a nest called a redd, which is an area in the gravel she
loosens up. The velocity of the water running over a redd must be high enough to oxygenate
the eggs.
Redd size varies with the species of salmonid, but can be as
large as 28 inches deep and 6 feet across for larger fish.
During spawning season, it is often visible as a lighter round or
oval depression in the gravels. However, later on, while the eggs are still developing, or
the youngest stages of the fish are present in the redd, the topmost gravels in the redd
may wash away. This can make it difficult, if not impossible to distinguish the redd from
its surroundings.
The rate at which the eggs develop depends on the water
temperature, but, generally, fry hatch from the eggs after 50-70 days. Each tiny fish is
attached to the yolk sac from its egg. Over the net 35-45 days, the fry move through the
gravel toward the surface, absorbing the yolk in route. Disturbance of a redd can kill
developing eggs and fry.
When the fry reach the surface, they are free-swimming, and are
termed alevins. The length of time smolt remain in their natal river before
entering the ocean depends on the species, and even the particular population. Populations
that spend a longer period of time in streams and rivers are more sensitive to changes in
the river. As anadromous salmonids swim downstream, they feed and grow on their way to the
ocean They will live in the ocean for a number of months or years, the time period
depending on the species, population, and environmental conditions, before returning to
their natal river or stream to spawn.
MANAGEMENT STRATEGY
Until recently, raising fish in hatcheries and barging them around barriers such
as dams was the major strategy for reversing fisheries depletion. However, continued
decline has focused fisheries management on a new approach, that of ecosystem and habitat
restoration and protection. Managers are opting to minimize and repair disturbance of
natural systems wherever possible.
For suction dredgers, this means that many streams and rivers are
closed to dredging during the period that salmonids spawn, the eggs mature and hatch, and
the fry move up through the gravels. Because of the wide variation between streams and
between fish stocks (a population that reproduces independently from other populations),
closures are determined on a local basis. Respecting these closures is the first step
suction dredgers can take to help protect the fish.
SUCTION DREDGING CHECKLIST
The following Suction Dredging Checklist outlines precautions dredgers should
take to help maintain healthy salmonid populations when streams are open for mining. One
of the most important precautions is depositing loosened gravels in a manner so that
salmonids will not use them for spawning, as these gravels may wash out before the fry are
fully developed.
Introduction:
Following laws and regulations related to suction dredging helps to protect river
ecosystems. These statutes have been designed to preserve rivers and protect fish
populationsfor example, to prohibit dredging during the time that eggs and fry are
present in the gravels. Since there is so much variation between rivers, many of the
regulations, such as closures, must be determined on an individuals basis. Rivers
containing endangered species of fish or other aquatic animals may be closed year-round.
This section gives pointers for reducing the impacts of suction
dredging on rivers and the plants and animals they contain. The checklist begins the same
way suctions dredging does: obtaining needed permits and transporting dredges and other
equipment. Also covered are various activities associated with dredging including camping,
securing dredges, and using gasoline engines, as well as dredging itself. The checklist
was developed with the assistance of miners, scientists, and forest managers. It does not
replace existing laws and regulations.
- Follow the law and create good will through mutual
respect.
- Identify where and when mining is allowed or prohibited.
- Obtain needed permits.
- Checks with the local USDA Forest Service District Ranger
for guidance on which laws and regulations apply to the specific lands. Recognize that
different laws apply to different lands. Recognize that different laws apply to different
lands. For example, depending on the land status, the Acquired Lands Leasing Acts or the
1872 Mining Law may apply.
- Review USDA Forest Service Surface Use Regulations for
locatable minerals.
- Review other rules and regulations that may cover, but are
not limited to, the following: annual and seasonal stream closures, nozzle and hose
diameters, engine horsepower and noise levels, winch use, operations in spawning areas,
hydraulicking and bank mining, stream flow disturbance, damming, volume of material,
restoration, woody debris, spill, and sanitary waste.
- If applicable, file a notice of intention (NOI) to operate
with the District Ranger.
- If required, submit a proposed plan of operation to the
District Ranger.
- Obtain permits and file notices and plans of operation
with other Federal and State agencies as required.
Camping Near Rivers and Streams - Treading Lightly
The land bordering rivers and streams, known as the riparian area, is vitally
important to many species of wildlife. If possible, camp outside of the riparian area.
- Minimize camping impacts, such as trails and clearings.
- Avoid trampling vegetation.
- Do not use soaps or detergents in or near river or
riparian areas.
- Dispose of garbage and human waste in a sanitary,
self-contained way and remove it to an approved disposal site.
- Keep the campsite clean to avoid pollution and maintain a
natural experience for other users.
Transporting And Storing Equipment - Heavy-Duty
Protection
Overhanging banks keep the edges of streams cool and are used for cover by fish.
when portions of the streambank are damaged, erosion occurs and soil washes into the
stream, silting in gravel beds and causing increased turbidity in the stream. The ribbon
of land adjacent to streams, often a border of thick, multilayered vegetation, hosts
numerous wildlife habitat.
- Minimize impacts of bringing in and storing equipment.
- Avoid Streambank damage.
- Avoid driving off-road through riparian areas.
Securing Dredges With Lines - Line Up For Safety
Lines securing dredges can be a safety hazard for rafters and boaters if the
lines block passage. Another concern is injury to trees where equipment has been tied.
- Make sure cables and ropes dont block passage for
boats and rafts; lines spanning the river should be at least 6 feet above the water
surface.
Flag lines to make them easy to see. When anchoring a cable to a tree, protect the tree by
wrapping it with an old inner tube, or by covering the cable with a piece of old hose.
- Make sure trees along the cable are not damaged.
- Remove all cables, ropes, and inner tubes when dredging is
completed.
Using Gasoline Engines - Fuel For Concern
Other stream users often express concerns about the gasoline engines on dredges,
complaining, for example, about noise and fumes. An additional problem can be leakage of
petroleum products from engines or storage containers.
- Install a muffler on engine to minimize noise.
- Prevent fuel and oil leaks into water or riparian areas,
from the engine as well as from storage containers.
- Outfit the suction dredge with an oil pan.
- To prevent gasoline from entering the water, place a
polypropylene pad around the has tank when refueling. The pad absorbs petroleum products
but repels water.
- In case of a leak, do not disperse oil or fuel with
detergent. This makes spills harder to clean up and increases the damage to aquatic
wildlife.
Leaving Boulders and Large Woody Debris - Best Left Alone
Large boulders and woody debris are important elements in the creation of fish
habitat because large pools form adjacent to them. During periods of hot weather, the
cooler deep sections of the pools are essential for fish survival. Fish use large woody
debris for cover.
- Do not remove large boulders and large woody debris from
the stream.
- Preserving Overhanging Banks - Watch Out Above
- Destabilization of overhanging banks by undercutting often
causes banks to collapse into the streams. This increases sediment in the water and
decreases habitat for fish, which often seek cover under banks.
- Do not undermine overhanging banks with the suction
dredge.
- Do not remove protruding boulders or woody debris from
banks.
- Make sure gravel piles do not deflect high water against
banks.
Placing Cobble and Tailing Piles Effectively Helps
Protect and Preserve Salmon Spawning Grounds - Tell Tail Signs - Redd Means
STOP
When salmonids spawn, eggs hatch, and the fry move up through the gravels,
streams and river are generally closed to suction dredging. This protects eggs and fry
from being sucked through dredges or suffocated by tailings or sediment.
While seasonal closures protect eggs and fry from direct impacts, they may not alleviate a
potential problem that occurs if salmonids spawn in gravels left by dredgers. If these
gravels are loose, and wash downriver during high waters, any redds contained within these
gravels may be destroyed.
Cobble and tailing piles can obstruct passage for boaters and rafters. Another problem can
be cobbles and tailings left on or near the bank. During dry periods, when the water level
drops, the piles become exposed. Unlikely to be flushed away by high waters, these piles
can remain for many years, particularly during periods of drought.
- Dont stack cobbles or deposit tailings on or near
the bank.
- Distribute cobbles as broadly as possible in the channel.
- Periodically stop operations and pivot the back of the
dredge to help spread tailings.
- Deposit tailings further from the dredge by extending the
end of the sluice.
- Follow regulations concerning where and when suction
dredging is permitted.
- Piles can be flattened using hydraulic force.
- Controlling Silt discharge Into Water - Get a Clear Idea
Depending upon site-specific conditions, silt can settle on and suffocate redds when
dredging coincides with spawning or movement of fry through the gravels. This is one of
the reasons dredging is seldom allowed during that time period. Large amounts of silt and
fine sand can have a big impact, especially in small streams, which have less capacity for
flushing.
- Look behind you. Evaluate your impacts and consider
reasonable ways to minimize them.
- Do not dredge streambanks.
Toxic Materials And Rubbish in Streams - Take-Out Menu
Suction dredgers can help restore streams by removing natural and introduced lead
and mercury from the streambeds. Within a streambed, lead weights and shot are ground by
the constantly moving sand, which removes small flakes of lead. The flakes oxidize easily,
which releases the lead into the environment.
- Lead recovered by suction dredging can be recycled. In
many cases, local mining organizations can act as central collection points.
- Sometimes mercury is encountered on stream bottoms. Even
in modest amounts, mercury can be quite toxic. Contact your local Forest Service office
and appropriate State agency for information about proper disposal of materials you find
in streams.
- Dispose of removed material safely and according to the
law.
- Be careful when dredging in areas where sediments are
likely to contain toxic substances, such as near discharge areas from towns and industrial
sites.
- Discard refuse in an approved disposal area.
Thanks to Gold and Treasure Hunter Magazine All rights reserved.
|