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P
parent material (soil) - (3) the unconsolidated more or
less chemically weathered mineral or organic matter from which the
upper level of the soil profile has developed.
particle size - (4) the dimension of particles. Commonly
measured by sieving, settling velocities and image analysis. Particle
sizes include the various types of coarse fragments (> 2mm),
such as boulders, stones and gravel, and the different soil sizes
(< 2mm), sand (2 mm - 62.5 µm), silt (2 µm
- 62.5 µm) and clay (< 2 µm).
Passerine birds - (3) birds of the order Passeriformes,
which include perching birds and songbirds such as blackbirds, jays,
finches, warblers, and sparrows. More than half of all known birds
belong to this order.
patent - (1) a written title to land granted by the government
after fulfilling certain obligations. A mining claim could be patented
after $500 worth of work had been completed on the property. The
owner is then relieved of annual assessment work, but the land is
taxable. (3) the instrument by which the Federal Government conveys
title to the public lands.
percolation - (4) downward flow of water within an unsaturated
porous medium.
perennial stream - (1) a stream or stretch of a stream that
flows continuously throughout the year.
periphyton - (3) microscopic plants and animals that are
firmly attached to such solid surfaces under water such as rocks,
logs, pilings, and other structures.
perennial stream - (3) a stream that flows continuously
during all seasons of the year.
perennial vegetation - (3) plants that have a life cycle
of 3 or more years.
pH (hydrogen ion concentration) - (5) - A convenient method
expressing the acidity or basicity of a solution in terms of the
logarithm of the reciprocal (negative logarithm) of the hydrogen
ion concentration. The pH scale runs from 0-14; a value of 7.0 indicates
a neutral solution. Values above pH 7.0 indicate basicity (basic
solutions); those below pH 7.0 indicate acidity (acid solutions).
Natural waters usually have a pH between 6.5 and 8.5. Because the
units are derived from common logarithms, a difference of one pH
unit indicates a tenfold difference in acidity; similarly, a difference
of two units indicates a hundredfold difference. The term is originally
derived from potential of Hydrogen.
photosynthesis - (3) the manufacture by plants of carbohydrates
and oxygen from carbon dioxide and water in the presence of chlorophyll,
using sunlight as an energy source.
phreatophyte - (3) a plant that absorbs its water from a
permanent supply in the ground.
phyla - (3) in taxonomy, the primary divisions of the plant
and animal kingdom.
pit lake - (3) water body that forms at the bottom of an
open pit mine when mining extends below the water table.
placer - (2) a mineral concentration resulting from the
weathering process, usually involving water. Placer deposits are
typically composed of heavy minerals, with gold, platinum, tin and
diamonds being the most important. Most typically, placer mining
occurs in gravel deposits resulting from stream deposition. (3)
an alluvial deposit of sand and gravel containing valuable minerals
such as gold.
plankton - (3) suspended, floating, or weakly swimming microscopic
plants and animals in the water that provide a basis for the aquatic
food chain. Plankton include bacteria, algae, protozoans, rotifers,
larvae, and small crustaceans.
playa - (3) a dried-up, flat-floored, area consiiting of
thin evenly layered sheets of fine clay, silt, or sand, representing
the bottom of a shallow, undrained desert lake basin in which water
accumulates and is quickly evaporated, usually leaving deposits
of soluble salts.
plume - (3) a visible or measurable discharge of a contaminant
from a given point of origin. A plume can be visible or thermal
in water, or visible in the air.
polishing pond - (4) the last in a series of treatment or
settling ponds through which mill effluent, or other potentially
contaminated drainage, flows before being discharged into the natural
environment. The term polishing infers that only minor improvements
in water quality are required or anticipated.
pollutant - (4) see contaminant.
population - (3) within a species, a distinct group of individuals
that tend to mate ony with members of the group. Because of generations
of inbreeding, members of a population tend to have similar genetic
characteristics.
porosity - (3) a rock, soil, or other material's property
of containing interstices. Porosity is commonly expressed as a percentage
of the bulk volume of a material occupied by interstices.
portal - (2)(a) the surface entrance to a drift,
tunnel or adit; (b) the entrance to a mine. (4) surface entrance
to an adit, level, incline or decline.
precious metals - (3) a general term for gold, silver, or
any of the mineral of the platinum group. (4) a general term applied
to the relatively more expensive metals, such as gold, silver and
platinum, which based on cost can be distinguished from base
metals and the alkali and alkali earth metals. Sometimes called
the noble metals. Costs vary according to supply and demand.
pregnant solution - (2) metal-laden solution (cyanide, acid,
etc.) resulting from a leach process. See also barren
solution.
prey base - (3) populations and types of prey species available
to predators, for example, fish species and populations available
to river otters.
primary mineral - (4) a mineral that came into existence
at the time the rock formed and that retains its original composition
and form. Includes mineral formed by igneous, hydrothermal,
or pneumatolytic processes. See also secondary mineral.
primary producers - (3) green plants that can manufacture
food from simple organic substances.
primary production - (3) the production of organic substances
by photosynthesis; the amount of material so produced per unit time.
probable maximum earthquake - (4) a geotechnical engineering
parameter determined by the maximum recorded earthquake at the site,
the maximum recorded earthquake for a site in a similar location
for which the historic data are available, or the one-in-10,000-year
earthquake predicted statistically from previous earthquakes in
the region. See also return period.
probable maximum flood - (4) the most severe precipitation
and/or snowmelt event considered reasonably possible at a particular
geographical location. A site-specific determination based on the
possible range in meteorological and hydrological events and conditions.
Variables include the duration, the area and the time of year. Usually
defined as the 1:10,000 year flood or two or three times the 1:200
year flood. See also return period and flood recurrence
interval.
probable maximum precipitation - (3) the precipitation that
may be expected from the most severe combination of critical meteorolgic
conditions and that is reasonably possible in an area as found in
the National Weather Service Hydrometeorological Reports.
process water - (4) water used in the milling process.
proper functioning condition (riparian-wetland areas) -
(3) the condition where: (a) enough vegetation, landform, or large
woody debris is present to dissipate the stream energy of high water
flows, thereby reducing erosion and improving water quality; (b)
sediments are filtered, bedload is captured, and floodplains develop;
(c) flood water retention and ground water recharge are improved,
root masses that stabilize stream banks against cutting action develop,
and diverse ponding and channel characteristics are created to provide
the habitat and the water depth, duration, and temperature needed
for fish production, waterfowl breeding, and other uses; and (d)
greater biodiversity is supported.
prospect - (2)(a) a mineral property, the value of which
has not been proved by exploration; (b) non-producing mining property
under development or considered worthy of such attention.
PRP - (2) Potentially Responsible Party
pyrite - (1) a common iron sulfide mineral.
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