diff --git a/OpenRa.Game/OpenRa.Game.csproj b/OpenRa.Game/OpenRa.Game.csproj
index a513bba673..b25d8b6c87 100644
--- a/OpenRa.Game/OpenRa.Game.csproj
+++ b/OpenRa.Game/OpenRa.Game.csproj
@@ -161,6 +161,7 @@
     <Compile Include="Traits\RenderUnitRotor.cs" />
     <Compile Include="Traits\RenderUnitSpinner.cs" />
     <Compile Include="Traits\RenderUnitTurreted.cs" />
+    <Compile Include="Traits\SeedsOre.cs" />
     <Compile Include="Traits\TraitsInterfaces.cs" />
     <Compile Include="Traits\Tree.cs" />
     <Compile Include="Traits\Turreted.cs" />
diff --git a/OpenRa.Game/Ore.cs b/OpenRa.Game/Ore.cs
index f81b39ebe5..dfbd508b58 100644
--- a/OpenRa.Game/Ore.cs
+++ b/OpenRa.Game/Ore.cs
@@ -8,9 +8,19 @@ namespace OpenRa.Game
 {
 	public static class Ore
 	{
-		/* todo: deal with ore pits */
+		public static void AddOre(this Map map, int i, int j)
+		{
+			if (Rules.General.OreSpreads)
+				if (map.ContainsOre(i, j) && map.MapTiles[i, j].density < 12)
+					map.MapTiles[i, j].density++;
+				else if (map.MapTiles[i, j].overlay == 0xff)
+				{
+					map.MapTiles[i, j].overlay = ChooseOre();
+					map.MapTiles[i, j].density = 1;
+				}
+		}
 
-		static bool CanSpreadInto(int i, int j)
+		public static bool CanSpreadInto(int i, int j)
 		{
 			if (Game.BuildingInfluence.GetBuildingAt(new int2(i, j)) != null)
 				return false;
@@ -72,13 +82,6 @@ namespace OpenRa.Game
 				}
 		}
 
-		static IEnumerable<int2> AdjacentTiles(int2 p)
-		{
-			for (var u = -1; u < 2; u++)
-				for (var v = -1; v < 2; v++)
-					yield return new int2(u, v) + p;
-		}
-
 		static byte GetOreDensity(this Map map, int i, int j)
 		{
 			int sum = 0;
diff --git a/OpenRa.Game/Traits/SeedsOre.cs b/OpenRa.Game/Traits/SeedsOre.cs
new file mode 100644
index 0000000000..f41a34076b
--- /dev/null
+++ b/OpenRa.Game/Traits/SeedsOre.cs
@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Game.Traits
+{
+	class SeedsOre : ITick
+	{
+		public SeedsOre( Actor self ) {}
+
+		const double OreSeedProbability = .05;
+
+		public void Tick(Actor self)
+		{
+			for (var j = -1; j < 2; j++)
+				for (var i = -1; i < 2; i++)
+					if (Game.SharedRandom.NextDouble() < OreSeedProbability)
+						if (Ore.CanSpreadInto(self.Location.X + i, self.Location.Y + j))
+							Rules.Map.AddOre(self.Location.X + i, self.Location.Y + j);
+		}
+	}
+}
diff --git a/trees.ini b/trees.ini
index 40a1f283aa..437e0b7614 100644
--- a/trees.ini
+++ b/trees.ini
@@ -183,7 +183,7 @@ Selectable=no
 
 [MINE]
 Description=Ore Pit
-Traits=Building, RenderBuilding
+Traits=Building, RenderBuilding, SeedsOre
 Footprint=x
 Dimensions=1,1
 Name=MINE